Circuit protection devices, systems, and methods for hazardous location compliance with enhanced safety intelligence

Abstract

The present invention describes a compliant circuit protection device for use in hazardous environments without creating a risk of ignition of potentially explosive environmental conditions. Sensing features and systems can evaluate wiring limitations and user-selected compatibility settings, detect loose connections and operating parameters to ensure safe operation of the device, and intelligently diagnose and manage concerns of the circuit protection device and the larger electrical system.

Description

BACKGROUND OF THE INVENTION

[0001] The field of the present invention relates generally to circuit protection devices, and more particularly to circuit protection devices compliant with hazardous environments, including intelligent feedback control to ensure enhanced safety, operational safety, and maintenance during the proper installation and use of circuit protection devices in power systems operating in hazardous environments.

[0002] To meet the needs of power systems that supply power to various electrical loads, there are various different types of circuit protection devices. For example, various different devices and components are known that provide an open circuit function between a power supply circuit and an electrical load. With such devices, output power can be selectively switched from the power supply manually or automatically to facilitate the maintenance of the power system and to address over-electrical fault conditions. Circuit breaker devices and fuse disconnect switch devices are two well-known types of devices that each provide different capabilities for responding to overcurrent and electrical fault conditions and electrically isolate the load-side electrical equipment from the line-side power supply circuit, thereby protecting the load-side equipment and circuits from other damaging overcurrent conditions in the power system.

[0003] While known circuit protector disconnect devices can be used to meet the needs of many electrical systems, they are still disadvantageous in some respects for certain types of electrical systems and applications where the circuit protector is located in a hazardous location. Therefore, existing circuit protector disconnect devices have not fully met the market demand. Thus, improvement is needed. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] The following drawings are used to describe non-limiting and non-exhaustive embodiments, where like reference numerals refer to like parts throughout the drawings unless otherwise specified.

[0005] Figure 1 is a perspective view of a compliant hazardous location arc-free circuit protection device according to a first exemplary embodiment of the present invention.

[0006] Figure 2 is in an exemplary solid state configuration Figure 1 of the circuit protection device shown in a simplified schematic diagram.

[0007] Figure 3 is Figure 1 and Figure 2 a block diagram of the circuit protection device shown.

[0008] Figure 4 is Figures 1 to 3 a block diagram of the distribution board installation of the circuit protection device shown and shows alternative set inputs for powering different electrical loads.

[0009] Figure 5is to ensure that for Figure 4 a flowchart of an exemplary process algorithm that sets compatibility and fail-safe measures for the circuit protection device shown.

[0010] Figure 6 shows a detection technique for determining Figure 5 the wiring limitations of the algorithm shown.

[0011] Figure 7 shows a power sensor feedback system including Figures 1 to 3 the circuit protection device shown.

[0012] Figure 8 is a perspective view of a compliant hazardous location arcless circuit protection device according to a second exemplary embodiment of the present invention.

[0013] Figure 9 is a simplified schematic diagram of the Figure 8 circuit protection device shown in an exemplary hybrid configuration.

[0014] Figure 10 is Figure 8 and Figure 9 a block diagram of the circuit protection device shown.

[0015] Figure 11 schematically shows Figures 8 to 10 the thermal management features of the circuit protection device shown.

[0016] Figure 12 shows an exemplary distribution board including a compliant explosive location circuit protection device.

[0017] Figure 13 shows exemplary waveforms of the power voltage and current waveform characteristics of various different electrical loads that can be detected and managed by an exemplary embodiment of the compliant hazardous location arcless circuit protection device of the present invention.

[0018] Figure 14 shows exemplary current characteristic changes in a protected load circuit that can be detected and managed by an exemplary embodiment of the compliant hazardous location arcless circuit protection device of the present invention. DETAILED DESCRIPTION

[0019] To best understand the inventive concepts described herein, a discussion of the prior art is presented below as it relates to problems caused by power systems operating in hazardous locations, followed by an exemplary embodiment of a circuit protection device, system, and method that solves such problems and meets a long-standing but unmet need in the art.

[0020] I. Prior Art

[0021] Power systems sometimes operate in hazardous environments, posing a risk of explosion due to the ignition of surrounding gases, vapors, dusts, fibers, or flyings. Such hazardous environments may occur only, for example, in refineries, petrochemical plants, grain silos, wastewater and / or treatment facilities, and other industrial facilities where unstable conditions are generated in the surrounding environment, increasing the risk of fire or explosion. The temporary or continuous presence of combustible gases, combustible vapors, combustible dusts, or other flammable substances in the air poses a significant challenge to the overall safety and reliable operation of these facilities, including but not limited to the safe operation of the power system itself. In some cases, conventional circuit protection devices may generate ignition sources during normal operation and electrical faults. Therefore, many standards regarding the use of electrical products in explosive environments have been promulgated based on the assessment probability of explosion or fire risks to improve safety in hazardous locations.

[0022] For example, the Underwriter’s Laboratories (UL) standard UL 1203 specifies the standards for explosion-proof and dust-ignition-proof electrical equipment for hazardous locations. Currently, there are explosion-proof and dust-ignition-proof enclosures available that can be used to enclose or house electrical products, including but not necessarily limited to circuit protection devices that are not themselves explosion-proof and dust-ignition-proof. By combining appropriate explosion-proof and dust-ignition-proof enclosures, electrical equipment manufacturers can obtain UL certification, demonstrating compliance with the rating standards applicable to hazardous locations. UL certification is an important aspect of a manufacturer's ability to successfully market products in North America or any other market that accepts UL standard UL 1203.

[0023] The National Electrical Code (NEC) in the United States typically classifies hazardous locations by class and division. Class I locations are those where combustible vapors and gases may be present. Class II locations are those where combustible dusts are present. Class III locations are those that are made hazardous due to the presence of ignitable fibers or flyings. Class I, Division 1 covers locations where combustible gases or vapors may be present under normal operating conditions, during frequent repair or maintenance operations, or where a malfunction or incorrect operation of process equipment may also cause an electrical equipment failure simultaneously. Division 1 poses a greater explosion risk than, for example, Division 2, where combustible gases or vapors are typically handled in a closed system, confined within a suitable enclosure, or generally prevented by active mechanical ventilation.

[0024] The International Electrotechnical Commission (IEC) also classifies hazardous locations as Zone 0, Zone 1, or Zone 2, which represent locations where combustible gases or vapors are present in the air in quantities sufficient to produce an explosive or flammable mixture. As defined by the IEC, a Zone 0 location is one where combustible gases or vapors with an ignitable concentration are continuously present or present for long periods. A Zone 1 location is one where combustible gases or vapors with an ignitable concentration may be present or may frequently be present due to maintenance or repair operations, or due to leakage or possible release of combustible gases or vapors with an ignitable concentration, or is a location adjacent to a Zone 0 location where vapors with an ignitable concentration can be transmitted from the Zone 0 location.

[0025] Since electrical devices (such as those described below) can be ignition sources in some cases, explosion-proof, flame-retardant, or ignition-proof enclosures are typically provided in Class 1 or Class 2 locations of the NEC and / or Zone 1 or Zone 2 locations of the IEC to house electrical devices that would otherwise pose an ignition risk. In this document, the term "explosion-proof" or "flame-retardant" refers to an enclosure that is designed to contain an internal explosion of a specified combustible vapor-air mixture. Additionally, an explosion-proof enclosure must operate at a safe temperature relative to the surrounding air.

[0026] Known conventional circuit breaker devices, various types of switchgear devices, and contactor devices include input terminals that can be connected to a power source or line-side circuit, output terminals that can be connected to one or more electrical loads, and pairs of mechanical switch contacts between the corresponding input and output terminals. Each pair of mechanical switch contacts typically includes a stationary contact and a movable contact connected to an actuator element that moves the movable contact along a predetermined path toward and away from the stationary contact to connect and disconnect the circuit path through the device, thereby electrically connecting or disconnecting the input and output terminals. When the switch contacts are open, the device serves to isolate one or more electrical loads connected to the output terminals from the power source connected to the input terminals. The actuator element in the above-described mechanical switchgear can move automatically for circuit protection purposes to open the mechanical switch contacts in response to an overcurrent or fault condition in the line-side circuit and electrically isolate the electrical loads from the electrical fault condition to prevent them from being damaged, or the actuator element can be manually movable to electrically isolate the electrical loads from the line-side power source, thereby conserving energy, maintaining the load, etc.

[0027] Circuit breakers and fusible disconnect switch devices are two well-known types of devices that each provide different types of interrupting functions and circuit protection through mechanical switch contacts. The IEC includes the following related definitions: 2.2.11

[0029] Circuit breaker

[0030] Mechanical switching device, which is capable of making, carrying, and breaking current under normal circuit conditions and is also capable of making, carrying for a specified time, and breaking current under specified abnormal circuit conditions (such as a short circuit) [441-14-20] 2.2.9

[0032] Switch (mechanical)

[0033] Mechanical switching device, which is capable of making, carrying, and breaking current under normal circuit conditions which may include specified operating overload conditions and is also capable of carrying current for a specified time under specified abnormal circuit conditions (such as a short circuit) [441-14-10]

[0034] Note that the switch is capable of making but not breaking short-circuit current. 2.2.1

[0036] Switching device

[0037] Device designed to make or break current in one or more circuits [441-14-01]

[0038] Note that the switching device may perform one or both of these operations.

[0039] As can be seen from the above definitions, the difference between the circuit breaker defined in IEC 2.2.11 and the mechanical switch defined in IEC 2.2.9 lies in their ability to mechanically respond to abnormal circuit conditions. Specifically, the circuit breaker defined in IEC 2.2.11 can mechanically break a short-circuit condition, while the mechanical switch defined in IEC 2.2.9 cannot break a short-circuit condition. Therefore, an electrical fuse is sometimes used in combination with the mechanical switch of IEC 2.2.9 to achieve a fusible disconnecting switch, which can respond to a short-circuit condition by the operation of the fuse (i.e., the disconnection of the fuse) rather than by the operation of the mechanical switch contacts.

[0040] In either device of IEC 2.2.11 and IEC 2.2.9, automatic circuit protection can sometimes be provided only by the structural design and calibration of the circuit breaker structure or the fuse element structure in the fuse, provided that each achieves a predetermined time-current characteristic before the circuit is disconnected. NEC has defined these two basic types of overcurrent protection devices (OCPDs) as follows:

[0041] Fuse: An overcurrent protection device having a fusible part that is heated and melted by the passage of overcurrent to break the circuit.

[0042] Circuit breaker: A device designed to open and close a circuit in a non-automatic manner and to automatically open the circuit without damage to itself when a predetermined overcurrent is correctly applied within its rating.

[0043] The NEC also requires that the circuit be provided with a disconnecting means that is defined as a device or group of devices, or other means that can disconnect the circuit conductors from the source of the circuit conductors. Since fuses are designed to open only when overcurrent is experienced, fuses are typically used in combination with a separate disconnecting means (usually some form of disconnect switch), as required by NEC Article 240 in many cases. Since circuit breakers are designed to open and close under manual operation and in response to overcurrent, a separate disconnecting means is not required.

[0044] In some types of circuit protection devices, automatic circuit protection can be achieved by electrical sensors included in the device to monitor the actual circuit conditions, and in response to a predetermined circuit condition detected by the sensor, an electromechanical trip feature can be actuated to automatically open the movable contacts in response to detected overcurrent conditions (including overload and short - circuit conditions). Once tripped, a circuit breaker can be reset or reclosed through the switching contacts to restore the affected circuit, because circuit breakers are designed to open the circuit without damaging themselves, while fuses open the circuit through internal degradation of the fuse element, which causes the fuse element to no longer be able to carry current. Therefore, the fuse must be replaced after opening to restore the affected circuit. In some cases, a combination of circuit breakers and fuses is also desirable and selectively coordinated to extend the range of overcurrent conditions that can be addressed and to improve the response time.

[0045] Compared with the circuit protection devices described above, the "switching device" of IEC 2.2.1 as defined above only relates to making and breaking the current, and does not relate to making or breaking overcurrent conditions (i.e., overload conditions or short - circuit conditions). The "switching device" of IEC 2.2.1 thus provides a disconnecting function, but does not provide a circuit protection function. IEC 2.2.1 also does not require a mechanical switching device at all, but if a switching device that is not a circuit breaker device actually includes mechanical switch contacts, there may still be a risk of ignition when it is located in a hazardous environment.

[0046] More specifically, the operation of mechanical switch contacts for closing or opening an energized circuit, whether actuated manually by a user under normal circuit conditions or automatically under abnormal circuit conditions, can create an ignition source in a hazardous environment. Specifically, when the moving contact mechanically moves away from the stationary contact (i.e., moves from the closed position to the open position), an arc discharge often occurs between the switch contacts. A similar arc discharge can occur when the moving contact moves back towards the stationary contact to re-close the device. If such an arc discharge occurs between the switch contacts in the presence of a flammable gas, vapor, or substance, the arc discharge can ignite the gas, vapor, or substance. Although mechanical switch contacts are typically enclosed in a housing that houses a conventional circuit breaker or other mechanical switching device and an additional enclosure that is typically used with a switchboard or motor control center, etc., such housings and enclosures are generally not sufficient to isolate the arc from ignitable airborne elements. For this reason, known devices that include mechanical switch contacts are typically located in a separate explosion-proof enclosure and then housed in an environmental enclosure or a switch system (i.e., a switchboard), which can in turn be installed in a single large explosion-proof enclosure without the need for a separate explosion-proof enclosure for the switch located in Class I, Division 1 or 2 locations of the NEC or Zone 1 or 2 locations of the IEC to provide the necessary protection.

[0047] In the devices described above, although the circuit breaker mechanically interrupts a short-circuit condition, it experiences the most intense arc discharge condition and thus has the greatest likelihood of igniting a flammable gas, vapor, or substance in a hazardous location in terms of the original energy and temperature. Considering that many industrial power systems and loads operate at relatively high voltages and high currents, the arc energy and arc temperature under lower current overload conditions and normal conditions are also quite large and quite high, thus posing an ignition risk. Generally speaking, the ignition energy caused by fault energy is related to the magnitude of the current being interrupted, so the larger the current being interrupted, the greater the likelihood and severity of the arc discharge. For example, from the perspective of arc discharge, a disconnection of 65 kAIC is significantly more than a disconnection of 10 kAIC and is therefore more dangerous.

[0048] Available explosion-proof, fire-proof or ignition-proof enclosures effectively enable mechanical switching devices in Class 1, Division 2 or Class 2, Division 2 locations of the NEC or Zone 1 or Zone 2 locations of the IEC to operate safely, but typically incur additional costs, occupy valuable space in the power system, and impose a certain burden on the installation and maintenance of the power system over time. To access the circuit breaker device within an explosion-proof enclosure usually requires time-consuming removal of multiple fasteners, and after any maintenance procedure, all fasteners must be properly replaced to ensure the required safety of the explosion-proof enclosure. During the maintenance procedure, the area where the circuit breaker device is located is typically de-energized (i.e., disconnected), while the associated load-side processes are stopped to ensure safety during the maintenance procedure. From the perspective of an industrial facility, such downtime is costly, and it is important to limit or shorten the downtime. Therefore, in some cases, it would be desirable if the explosion-proof enclosure could be eliminated in Class 1, Division 2 or Class 2, Division 2 locations of the NEC or Zone 1 or Zone 2 locations of the IEC while still providing a safe circuit-breaking function in a hazardous environment. For this purpose, circuit protection devices designed to reduce the ignition risk are needed, but such devices are not typically available at present.

[0049] Solid-state circuit breaker devices are known, which provide the required circuit-breaking function through semiconductor switches or semiconductor devices such as, but not limited to, insulated gate bipolar transistors (IGBTs), metal-oxide semiconductor field-effect transistors (MOSFETs), and other known components, which are electrically operated in a known manner to block current flow through the device and thus electrically isolate the line-side circuit from the load-side circuit in response to a predetermined circuit condition without using mechanical switch contacts. Such solid-state switches can be implemented in a circuit breaker device or used in combination with a fuse to automatically address electrical fault conditions.

[0050] Solid-state switches advantageously eliminate the arc discharge associated with the displacement of mechanical switch contacts as described above, but still create a potential ignition source through the heat generated by the solid-state switches in use. Even if no arc discharge occurs during the switching operation of the device, depending on the type and concentration of combustible elements in the hazardous location, the surface temperature of the solid-state switch device can rise to a level where spontaneous combustion occurs due to the flash point temperature of a specific gas or flammable substance in the hazardous location.

[0051] When used in Class 1 or Class 2 locations of the NEC or Zone 1 or Zone 2 locations of the IEC, the connection terminals of solid state switching devices can also pose reliability issues and potential ignition sources. More specifically, when subjected to thermal cycling or vibration, the terminals can tend to loosen over time. Under certain operating conditions, at the terminal locations, loose terminal connections can lead to overheating and potential ignition sources (if not arcing). Poor quality terminal connections can also cause overheating of the conductor structure (sometimes referred to as a bus) in the device, thereby creating further ignition problems in hazardous locations. Therefore, using only known solid state switching devices (without using other devices) does not ensure adequate safety in hazardous locations unless an explosion-proof enclosure is additionally used in Class 1 or Class 2 locations of the NEC or Zone 1 or Zone 2 locations of the IEC.

[0052] So-called hybrid interrupting devices are also known, which include a combination of semiconductor switches or semiconductor devices and mechanical switch contacts. Such hybrid devices can also be implemented in circuit breaker devices or used in combination with fuses to automatically address electrical fault conditions. From the perspective of potential ignition sources in hazardous locations, hybrid interrupting devices present a mixture of the above problems and do not ensure adequate safety if an explosion-proof enclosure is not additionally used in Class 1 or Class 2 locations of the NEC or Zone 1 or Zone 2 locations of the IEC.

[0053] II. Inventive Arcless Devices, Systems, and Methods for Hazardous Location Compliance 。

[0054] Exemplary embodiments of a circuit protection device are described herein that overcome the above problems and provide an enhanced level of safety for compliance with applicable standards in Class 1 or Class 2 locations of the NEC or Zone 1 or Zone 2 locations of the IEC, without necessarily requiring a separately provided explosion-proof, fire-proof, or ignition-proof enclosure. Thus, by eliminating such a separately provided explosion-proof, fire-proof, or ignition-proof enclosure, the exemplary circuit protection device described herein advantageously reduces costs and saves valuable space in switchboards, control centers, etc. The exemplary circuit protection device described herein also advantageously enables more effective maintenance and supervision of the power system. Some aspects of the method will be explicitly discussed and some will become apparent from the following description.

[0055] In a first aspect, an exemplary circuit protection device can be implemented in the form of a solid-state circuit protection device that has an arcless operation during the process of a switching device connecting or disconnecting a load-side circuit through a solid-state switching device, combined with enhanced features for addressing possible ignition sources at connection terminals, and / or includes thermal management features for addressing possible overheating of conductors in the solid-state switching device. Thus, when implemented in the form of a solid-state circuit breaker device, unlike conventional circuit breakers, such solid-state circuit breakers comply with hazardous location standards applicable to Class 1, Division 2 or Class 2, Division 2 locations of the NEC or Zone 1 or Zone 2 locations of the IEC, thereby making conventional explosion-proof, fire-proof or ignition-proof enclosures removable for certain applications.

[0056] In a second aspect, additional safety enhancements are achieved through intelligent control of the solid-state circuit protection device, which detects incompatible installations and setting selections by the device installer, detects inadequate or loose electrical connections to the device, and evaluates the operating conditions of the direct and indirect line-side and load-side circuits connected through the device. The intelligent control can employ fail-safe measures and implement a notification-disconnect function, with a better understanding of the actual state of the power system and diagnostic capabilities to identify problematic electrical conditions and their location relative to the device, thereby ensuring safe operation at the actual location of the device.

[0057] In a third aspect, a hybrid circuit protection device can be implemented in the form of a combination of a solid-state switching device and a mechanical switching device, and can also be combined with enhanced features for: isolating the arc between the mechanical switch contacts from the surrounding environment to prevent ignition in hazardous locations, and addressing possible ignition sources at connection terminals and / or including thermal management features to avoid possible overheating of conductive elements inside the hybrid device. Thus, unlike conventional hybrid circuit protection devices, such hybrid circuit protection devices comply with hazardous location standards applicable to Class 1, Division 2 or Class 2, Division 2 locations of the NEC or Zone 1 or Zone 2 locations of the IEC, and make conventional explosion-proof enclosures removable for certain applications.

[0058] In a fourth aspect, additional safety enhancements are achieved through intelligent control of the hybrid circuit protection device, which detects incompatible installations and setting selections by the device installer, detects inadequate or loose electrical connections to the device, and evaluates the operating conditions of the direct and indirect line-side and load-side circuits connected through the device. The intelligent control can employ fail-safe measures and implement a notification-disconnect function, with a better understanding of the actual state of the power system and diagnostic capabilities to identify problematic electrical conditions and their location relative to the device, thereby ensuring safe operation at the actual location of the device.

[0059] Although the discussion below is in the context of a circuit breaker device, the inventive concepts below are not necessarily limited to circuit breaker devices, but can be widely applied to other types of devices, examples of which were discussed above, which present similar problems from the perspective of ignition issues in hazardous locations. Similarly, although the inventive concepts are described in the context of hazardous locations such as Class 1 or 2 locations of the NEC or Zone 1 or 2 locations of the IEC, the benefits of the described concepts are not necessarily limited to Class 1 or 2 locations of the NEC or Zone 1 or 2 locations of the IEC, but can be more widely applied to other types of hazardous environments and, in some aspects, can be advantageously provided for non-hazardous locations as needed.

[0060] Figure 1 is a perspective view of a compliant hazardous environment circuit protection device 100 according to a first exemplary embodiment of the present invention. The circuit protection device 100 includes a housing 102 having opposing longitudinal sides 104, 106 and opposing transverse sides 108, 110 that are disposed generally orthogonally with respect to the longitudinal sides 104, 106. The housing 102 also includes a front side 112 and a rear side 114, and the front side 112 includes an optional digital display 116 that serves as an input / output element of the device 100. As shown, the display 116 visually indicates voltage, current, power, and energy readings to the device 100 and to people in the vicinity of the display 116.

[0061] The housing 102 of the device 100 is made of strategically selected or otherwise customized materials to withstand all possible electrical operating conditions, particularly all possible electrical fault conditions, including concurrent fault conditions that may be generated by an electrical power system protected in a Class 1 or 2 location of the NEC or a Zone 1 or 2 location of the IEC.

[0062] To be compliant in a Class 1 location of the NEC, the housing structure and housing material must also be further formulated to provide sufficient strength to withstand the vibrations and shock forces that may occur in an explosive environment, as well as to provide chemical resistance to withstand exposure to chemicals in an explosive environment that could otherwise adversely affect the integrity of the device 100. As used herein, "chemical resistance" refers to the strength of the housing material to prevent chemical erosion or solvent reaction. Chemical resistance in the housing 102 is the opposite of chemical reactivity, which can cause undesirable chemical effects and / or may undesirably generate heat and raise the temperature of the housing 102 when the housing 102 is exposed to certain chemicals. By having little or no reactivity to specified chemicals, chemical resistance involves the resistance of the housing 102 to corrosive or caustic substances in the environment, including but not limited to airborne gases and vapors.

[0063] UL 1203 defines a chemical test that can be applied to determine whether any formulation of a candidate material for the housing 102 is chemically resistant to Class I, Division 1 hazardous locations. Specifically, the UL 1203 chemical test requires that a sample housing (or sample housings) be fabricated from a formulation of the candidate material in the desired housing configuration and that the sample housing be exposed to saturated vapors in air that contain a variety of specified chemicals for an extended period of time. The specified chemicals for use in the UL 1203 chemical test include acetic acid, acetone, ammonium hydroxide, ASTM reference fuel C, diethyl ether, ethyl acetate, ethylene dichloride, furfural, n-hexane, methyl ethyl ketone, methanol, 2-nitropropane, and toluene. After the exposure for the specified period of time, the housing sample is inspected to ensure that the housing configuration of the sample is not damaged or shows signs of deterioration such as discoloration, swelling, shrinking, cracking, breaking, leaching, or dissolving. The housing sample that passes the inspection is then subjected to a fracture test and compared to the results of the fracture test before exposure to the chemicals. If the fracture force of the housing sample that has been chemically tested shows that the chemically tested housing sample can withstand at least 85% of the corresponding fracture force tested before exposure to the chemicals, the housing sample complies with UL 1203. Such UL 1203 compliance may be considered optional for use of the device 100 in locations that are not Class I, Division 1 locations, which include but are not necessarily limited to Class I, Division 2 locations or Zone 1 or Zone 2 locations of the IEC and locations that do not meet the applicable criteria for defining a hazardous area (i.e., non-hazardous locations).

[0064] By virtue of its manufacturing materials, the housing 102 should also exhibit chemical compatibility with the specific chemicals present in a given Class I, Division 1 or 2 location or Zone 1 or 2 location of the IEC. Chemical compatibility refers to the stability of the housing when exposed to substances in a hazardous location environment. If the housing 102 reacts chemically with substances in the environment, it is considered incompatible. Thus, given the number of different corrosive or caustic chemicals and substances used in various industrial facilities, it is recommended that compatibility testing be performed to confirm chemical compatibility. Different facilities involving different caustic or corrosive substances may require housings of different materials to address the issues that arise. If it is not practical to determine or economically provide a generally optimal housing or material formulation, strategic selection and custom formulation of the housing material may be required for some hazardous environments. In some cases, UL 1203 compliance of the housing may eliminate the need for chemical compatibility testing in the selected facility, and chemical compatibility testing may thus be considered optional.

[0065] The material used to fabricate the housing 102 can also be strategically selected or otherwise formulated and shaped to have a specific structure to achieve the thermal management and surface temperature objectives of the device 100 in operation. Some housing materials may exhibit better thermal properties for distributing and dissipating heat than others. For example, a specific polymer resin can be selected or customized and formulated or processed such that the housing 102, when protecting the power system, will improve the thermal performance of the device 100 in use both on the interior of the housing 102 and its outer surface area such that the outer surface area temperature remains at a level below the temperature at which ignition can occur in Class 1 or Class 2 locations of the NEC or Zone 1 or Zone 2 locations of the IEC.

[0066] For any given housing material, the shape and form factor of the housing 102 (including dimensions, profile, etc.) can either positively or negatively alter the overall thermal performance and surface temperature. For example, for a given device rating of the power system and operating voltage and current, a housing with a larger outer surface area will generally result in a lower surface temperature in use compared to a housing with a smaller outer surface area. The housing structure can be designed to optimize and balance the overall package size and configuration as well as the thermal performance.

[0067] In some embodiments, the housing 102 can be made of a metal or metal alloy, a non-metallic insulating material (such as a high-strength, high-performance plastic), or a combination of metal and non-metallic materials to alter the thermal performance and the other considerations noted above, namely, shock resistance and chemical resistance. A housing construction that is either fully or partially encapsulated is also possible. In some cases, the interior of the housing 102 can also be fully or partially filled with a dielectric material, dielectric fluid, potting material, or other filling medium (such as sand) to contain, absorb, or dissipate the heat and energy of the energized electrical conductors and switching components in the device 100, thereby ensuring that the surface temperature of the housing 102 will remain below the selected target temperature and thus providing a device 100 with the desired heat resistance rating or temperature rating.

[0068] In addition to the materials used in its fabrication, the structural design of the housing 102 can also take into account heat distribution and heat dissipation. The housing can be strategically configured to include more than one housing material throughout the housing 102 or at specific target locations within the housing. Housing sub-structures can be fabricated independently and provided for assembly to provide additional thermal insulation or thermal conductivity in desired regions of the housing, thereby selectively restricting and distributing heat in a strategic manner to the selected locations. Similarly, the wall thickness of the housing 102 can be varied to provide a greater or lesser degree of thermal conductivity and heat dissipation in selected portions of the structure or in certain regions of the housing structure at the most desired locations. Ducts, channels, or pits can be formed to strategically capture the generated heat and direct it more effectively to the desired location for dissipation. Heat dissipating materials, etc. can be included to improve heat absorption and heat dissipation.

[0069] Active cooling elements are also possible, where cooling fluid flows above or through the housing structure, and the housing structure includes suitable structures that facilitate active cooling. The active cooling elements can be provided as a self - contained unit or separately, such as in a switchboard application where multiple devices 100 are provided. The active cooling system counteracts the heat generated by the accumulation in closely - located devices 100 and mitigates the temperature effects that the devices 100 may have on each other.

[0070] The above - mentioned thermal management considerations can be achieved in various different combinations, some of which can offset or eliminate the need for other considerations. For example, in some applications, active cooling can eliminate the need for certain features of the housing, such as more complex shapes and form factors for dissipating heat on relatively complex surface areas.

[0071] The lateral sides 108, 110 of the housing 102 each include connection recesses 118, 120, and 122 for connecting to the line - side circuit and the load - side circuit respectively. Figure 1 In the example shown, three connection recesses 118, 120, and 122 are provided for connecting to a three - phase power supply on one of the sides 108, 110 respectively, and to a three - phase load - side device on the other side. The power supply and the load can each operate with alternating current (AC) or direct current (DC). The device 100 shown is configured as a circuit breaker and thus provides automatic circuit protection in response to a predetermined over - current condition, which can be selected by the user within a specific range and input into the device 100 via the display screen 116, via another user interface, or pre - programmed into the device. The device 100 can operate according to a specified time - current curve or trip curve suitable for providing adequate protection for the connected load.

[0072] The display 116 can be a multi - functional display that displays different screens in response to user activation. In some embodiments, the display 116 can be touch - sensitive, and the user makes selections by touching the selected area of the display according to the prompts. Input selectors (such as buttons, knobs, etc.) can be provided separately from the display 116 for the user to interact with the prompts and information presented on the display. Input selectors (such as toggle switches) can also be provided separately from the display 116 to be used as manually operable on - off switches, which can be manually operated intuitively by the user. Alternatively, the on - off feature can be built into the display 116 to facilitate operator use, thereby implementing the circuit breaker switch function for the connected load - side device. However, it should be recognized that in certain embodiments, the display 116 can be considered optional and need not be included at all.

[0073] Figure 2is a simplified schematic diagram of a circuit protection device 100 in an exemplary solid-state configuration. The device 100 includes input terminals 130a, 130b, and 130c, each of which is connected via a connecting cable, conduit, or wire to Figure 2 one phase of a three-phase power supply represented as the line-side circuit 132 in Figure 2 . The device 100 also includes output terminals 134a, 134b, 136c, each of which is connected to a load-side circuit 136, such as motors, fans, lighting fixtures, and other electrical equipment in an industrial facility, where ignitable gases, vapors, or substances may be airborne as indicated at 138. The output terminals 134a, 134b, 136c may likewise be connected to an electrical load via a connecting cable, conduit, or wire. Solid-state switching devices as shown at 140a, 140b, and 140c are arranged between respective corresponding pairs of the input terminals 130a, 130b, and 130c and the output terminals 134a, 134b, and 136c. Exemplary arrangements include series-connected pairs of insulated gate bipolar transistors (IGBTs) 142a, 142b, 142c, 142d that are connected in reverse to each other, where each pair of IGBTs 142a, 142b, 142c, 142d includes a varistor element 144 connected in parallel to the IGBT. The reversely-connected IGBTs in each pair exclude reverse current flowing from the load-side circuit 136 to the line-side circuit 132 through the IGBTs in a known manner.

[0074] The IGBTs 142a, 142b, 142c, 142d in each solid-state switching arrangement 140a, 140b, 140c are a form of semiconductor switch that is operable to allow current to flow from the line-side circuit 132 to the load-side circuit 136 between the corresponding input and output terminals (130a and 134a, 130b and 134b, and 130c and 134c), or to prevent current from flowing through the device 100 such that the load-side circuit 136 is electrically isolated from the line-side circuit 132. Briefly, a positive voltage applied to the gate terminal from the emitter of the IGBT causes electrons to be pulled towards the gate terminal across the body region of the IGBT. If the gate-emitter voltage is equal to or higher than the threshold voltage, sufficient electrons are pulled towards the gate to form a conductive channel across the body region, allowing current to flow from the collector to the emitter. If the gate-emitter voltage is below the threshold voltage, substantially no current can flow through the body region, such that the current between the input and output terminals can be enabled or disabled by controlling the gate-emitter voltage to connect or disconnect the output terminals of the device 100 from the input terminals via the IGBT. Equivalent types of semiconductor switch elements other than IGBT elements may likewise be employed, including but not limited to metal-oxide semiconductor field-effect transistor (MOSFET) elements, bipolar transistor elements, silicon-controlled rectifier elements (sometimes referred to as thyristors), etc. The number of semiconductor switch elements may be varied to be greater or less thanFigure 2 The quantity shown.

[0075] The varistor element 144 connected in parallel to each pair of IGBTs in the shown arrangement exhibits a relatively high resistance when exposed to normal operating voltage and a much lower resistance when exposed to a larger voltage (such as associated with an overvoltage condition and / or an electrical fault condition). When the varistor 144 operates in the low impedance mode, the impedance of the current path through the varistor 144 is significantly lower than that of the IGBT, otherwise significantly higher than that of the IGBT. This means that under normal conditions, the high impedance of the varistor causes all current to flow through the IGBT, but with the occurrence of an overvoltage condition, the varistor switches from the high impedance mode to the low impedance mode and diverts or transfers the overvoltage-induced current surge away from the IGBT towards the load-side circuit 136. As the overvoltage condition weakens, the varistor 144 can return to the high impedance mode. The varistor 144 advantageously allows, for example, motor surge current to flow through the device 100 while also allowing the IGBT to respond to an overcurrent condition after motor startup is complete. However, in other applications, the varistor 144 may be considered optional and may be omitted.

[0076] As another thermal management feature, the solid-state switching devices (e.g., IGBTs) 140a, 140b, and 140c in the arrangement can be encapsulated with strategically selected or otherwise formulated materials to improve the thermal performance of the switching devices 140a, 140b, and 140c and / or to improve heat dissipation and heat distribution during use. The encapsulation materials for the solid-state switching devices 140a, 140b, and 140c can be the same as or different from the encapsulation materials included in the housing construction, and specifically, the goal is to control or limit the operating temperature of the silicon in the solid-state switching devices during normal circuit operation or during overcurrent and electrical fault conditions to prevent the switching devices themselves or the housing 102 from overheating.

[0077] Although an exemplary solid-state switching arrangement is shown and described, other arrangements may also achieve the solid-state switching function in an arcless manner. As described above, solid-state switching devices avoid the type of arc discharge generated by mechanical switches, thus preventing such arc discharges from becoming a potential ignition source in Class 1, Division 2 locations of the NEC or Zone 1 or Zone 2 locations of the IEC.

[0078] In view of the hazardous environments in which the device 100 is to be used, reliable termination of the line-side and load-side cables to the input and output terminals is important, as loose connections can create heat and reliability issues, as well as possible ignition issues in hazardous locations. In NEC Section 2 locations or IEC Zone 1 or Zone 2 locations, the input and output terminals may be accessible from the exterior of the housing 102. Locking terminal connection assemblies and spring-biased terminal assemblies may be used to receive and retain the ends of the respective cables while reducing any tendency for the cable connections to loosen over time. However, in view of some of the device intelligence and fail-safe features described below, such locking terminal assemblies and spring-biased terminal connectors may be considered optional in NEC Section 2 locations or IEC Zone 1 or Zone 2 locations in some cases.

[0079] In NEC Section 1 locations, the input and output terminals may be further enclosed in additional housing portions to provide additional safety assurance. Such housing portions may be provided separately from the housing 102, or may be integrally formed as an extension of the housing 102 to isolate the input and output terminals from the explosive environment. In a contemplated embodiment, a removable cover element may be provided to access the input and output terminals and complete the electrical connection with the input and output terminals within the housing of the housing portion. Line-side and load-side cable connections may be further established, for example, by providing ingress protection, sealing, and grounding through armored cables and cable glands to safely pass line-side cables or load-side cables through the housing of each housing portion. When used with armored cables, a grounding to earth path may be established via a cable gland. However, in all embodiments, armored cables are not required and may not be used. Cable glands may also be used with non-armored cables.

[0080] The housing 102 may be designed and manufactured with thermal management considerations in mind to maintain surface temperatures below applicable limits for a given installation in a Section 1 location of the NEC, and in some embodiments, the housing 102 may be fully or partially explosion proof in compliance with applicable standards for hazardous locations, albeit providing a relatively smaller and more economical housing than a conventional, larger, and separately provided explosion proof enclosure that would typically contain the entire circuit protection device. The housing 102 and the portion thereof defining the enclosure for the terminals may also include a vacuum chamber, or may be filled with a dielectric fluid, dielectric material, or inert gas to reduce or prevent arcing at the terminal / cable interface or other possible ignition sources. Sand fill, arc quenching fill, or other known encapsulation techniques may also be used to address possible arcing issues within the device 100. The device intelligence and fail-safe features described below provide additional assurance and safety to address ignition source issues at the terminal / cable interface, and may make some of the aforementioned features optional for Section 1 locations of the NEC.

[0081] To address the possible static charge accumulation problem (which creates a potential ignition source in the Class 1, Division 1 locations of the NEC), Figure 2 the connection of the housing 102 to the electrical ground 146 is shown. Briefly, static electricity is the result of an electromagnetic imbalance between negative and positive charges in an object. Charging of the housing surface can be generated by surface charges involving another object (especially the insulated portion of the housing) or by charge induction on the conductive portion of the housing. Surface charging can also occur during exposure to a high voltage DC power source, which will cause ions to attach to the housing surface.

[0082] Regardless of how the surface charging actually occurs, the connection to the ground 146 allows any charge accumulation on the housing 102 to be safely dissipated without creating an ignition source in the combustible / hazardous area. The housing 102 can be grounded to the earth ground or chassis ground via a line wire or line conductor that is connected to the outer surface of the housing 102. In this way, any charging on the exterior of the housing 102 will quickly dissipate as an electric current to the ground and avoid a high voltage discharge event, which typically manifests as a spark or shock that can be generated and cause ignition in the presence of flammable air through a person or a tool used by a person.

[0083] The housing 102 itself can also be made in whole or in part of an anti-static polymer or anti-static material that is weakly conductive from the perspective of charge accumulation but is still considered insulating and non-conductive from the perspective of the power system protected by the device 100. In the first case, relative to non-anti-static materials, the anti-static material can improve the housing performance by reducing any tendency for the housing to become charged, and this is another consideration in strategically selecting or otherwise formulating one or more materials to be used in housing manufacture. If desired, an anti-static coating, encapsulation, or shell can be provided on the outer surface of the housing, but chemical resistance and compatibility must still be ensured as described above.

[0084] Although Figure 2 a single ground connection is shown, more than one ground connection can be provided at any desired location in the structure of the device 100. In addition to or in lieu of the ground conductor connected to the exterior of the device housing 102 as described above, a ground conductor can be provided inside the device housing 102. When using an armored cable that already includes a ground path to the earth to establish line-side and load-side connections to the terminals 130a, 130b, and 130c of the device 100, a ground connection for the housing 102 can also be established via a cable connector (such as a cable gland). Of course, in some cases, a non-armored cable with or without a cable gland can be used while still eliminating the ignition source in the device 100 and addressing the static electricity problem through an alternative ground connection.

[0085] In NEC Division 2 locations or IEC Zone 1 or Zone 2 locations, the device will typically be protected by an enclosure rather than an explosion-proof enclosure, so electrostatic problems and discharge events are not likely to occur. Thus, in a device 100 for use in an NEC Division 2 location or an IEC Zone 1 or Zone 2 location, connection to ground 146 may or may not be necessary or desirable and may thus be considered optional. However, with the device 100, the enclosures containing one or more devices 100 do not need to be explosion-proof, and the conventionally provided explosion-proof enclosures may be omitted.

[0086] Figure 3 is a block diagram of a circuit protection device 100. The device 100 includes a processor-based microcontroller that includes a processor 150 and a storage device 152. Executable instructions, commands, and control algorithms, as well as other data and information required to properly operate the device 100, are stored in the memory. The memory 152 of the processor-based device may be, for example, a random access memory (RAM), as well as other forms of memory used in conjunction with the RAM memory, including but not limited to flash memory (FLASH), programmable read-only memory (PROM), and electrically erasable programmable read-only memory (EEPROM).

[0087] As used herein, the term "processor-based" microcontroller shall refer not only to a controller device that includes a processor or microprocessor as shown, but also to other equivalent elements, such as a microcomputer, a programmable logic controller, a reduced instruction set (RISC) circuit, an application specific integrated circuit, and other programmable circuits, logic circuits, their equivalents, and any other circuit or processor capable of performing the functions described hereinafter. The processor-based devices listed above are merely exemplary and are not intended to limit in any way the definition and / or meaning of the term "processor-based".

[0088] The device 100 also includes sensors 154, 156, and 158 provided with numbers 1 to n, where n is equal to the number of switching poles in the device 100. Thus, for Figure 1 and Figure 2 the illustrated three-pole device 100, three sensors of each type may be included, which respectively detect current, voltage, and temperature at corresponding locations in the device to evaluate the actual operating circuit conditions in the device. The sensors 154, 156, and / or 158 then provide inputs to the processor 150. Thus, with the sensors 154, 156, and / or 158, the processor 150 has real-time information about the current through each of the solid-state devices 162 numbered 1 to n, where n is equal to the number of switching poles in the device 100.

[0089] Monitor the detected current and compare it with a baseline current condition, such as a time - current curve programmed and stored in memory 152 or the trip unit 160. By comparing the detected current with the baseline current condition, a decision can be made by the processor 150 to control the solid - state switching element 162 by controlling the output voltage to the gate - emitter voltage in the IGBT as described above, thereby stopping the conduction of current to protect the load side from damaging currents. In some embodiments, the trip unit 160 allows the user to select settings for the operation of the trip unit 160 and change the time - current response of the device 100 within a predetermined limit. As one such example, the user can select the current rating of the device 100 at a value from 50 A to 100 A, and the trip unit 160 applies an appropriate time - current curve for the selected current rating.

[0090] The detected voltage can likewise be monitored and used to make a control decision on whether to operate the solid - state switching element 162 to protect the load - side circuit and components from adverse operating conditions. Since voltage and current are related, the detected voltage can be compared with the detected current to facilitate the assessment of the health of the device 100, the identification of errors, and the diagnosis and troubleshooting of the power system. As additional fail - safe measures, the voltage and current can be calculated from the sensed parameters and compared with the sensor feedback to detect error conditions.

[0091] The detected temperature can likewise be monitored and used to make a control decision on whether to operate the solid - state switching element 162 to protect the load - side circuit and components from adverse operating conditions. Additionally, the detected temperature can ensure that the conductors in the device 100 operate below the rated temperature for the particular hazardous location in which they are located. For example, if the rated temperature is 200°F, when the operating temperature indicated by the temperature sensor rises to a temperature approaching 200°F that could ignite an airborne gas, vapor, or substance in a Class 1 or 2 location of the NEC or a Zone 1 or 2 location of the IEC, the processor 150 can operate the solid - state switch to disconnect and stop the current.

[0092] The processor 150 communicates with the input / output display 116 to provide feedback to the user and accept input via the display 116.

[0093] In the example shown, the processor 150 receives line - side power via the power converter circuit 163. When it is desired to supply direct current (DC) power to the processor 150 at a reduced voltage in a known manner, the power converter circuit 163 includes a buck component and an analog - to - digital conversion component. Converting the line power to an appropriate level to power the electronic device obviates any need for a separate power source (such as a battery, etc.) or a separately provided power line for the electronic circuits and controls that would otherwise be necessary. However, in some embodiments, such a separate power source may indeed be included if desired or needed. The controls described can be implemented in an electronic package in various arrangements on one or more circuit boards, and the algorithmic control features are programmed and stored in the device memory.

[0094] Also included is a communication element 164 that can transmit data to a remote location, as well as other devices 100 as further described below, to evaluate the operation of the larger power system with respect to the local and remote locations of any particular device 100. Wireless and non - wireless transmission of the data of interest is possible, where the data of interest includes, but is not limited to, current data, voltage data, temperature data, on - off state data of solid - state switch elements, selected setting data, trip - time data, etc., and such data can be stored and archived locally and remotely for power - system analysis over time. As described below, wiring - size data and / or ampacity - limit data can be transmitted to enhance the safety of devices in a 1 - or 2 - segment location of the NEC or a Zone 1 location of the IEC. Remote actuation of the device 100 is also possible via the communication element 164 for power - system maintenance or coordination of circuit protection, via communication with other circuit - protection devices and / or remote devices that assist in the manual or automatic monitoring and management of the power system.

[0095] Although an exemplary architecture of the device 100 has been described, it should be understood that Figure 3 certain of the elements shown may be considered optional to provide more basic functionality. Additionally, additional elements can be added to make the operation of the device 100 more complete and intelligent, and to provide additional functionality beyond circuit - protection and circuit - interruption functions.

[0096] Figure 4 is a block diagram of the circuit - protection device 100, showing an optional set - input feature of the device to power different electrical loads having different current requirements. Three circuit - protection devices 100A, 100B, and 100C are shown connected between a line - side power source 132 and corresponding first, second, and third electrical loads 170, 172, and 174, respectively. Each circuit - protection device 100A, 100B, 100C includes a user - selectable set input 176 that can define, for example, the maximum current limit, sometimes referred to as the ampacity limit, that the loads 170, 172, and 174 can safely handle.

[0097] In an envisioned embodiment, each of the devices 100A, 100B, 100C can operate under a current-carrying capacity limit in the range of 50A to 100A to serve different loads, where the user selects the available current-carrying capacity limit within the provided range. Thus, and by way of example, each of the devices 100A, 100B, and / or 100C can operate at a 60A current-carrying capacity limit, an 80A current-carrying capacity limit, and a 100A current-carrying capacity limit to power corresponding electrical loads having 60A, 80A, and 100A current-carrying capacity limits. In various non-limiting examples, the current-carrying capacity limit setting for each of the devices 100A, 100B, and / or 100C is input by the user via the display 116( Figure 1 ), another input element provided on the device, or via a processor-based remote device 178 that communicates with the devices 100A, 100B, and / or 100C. Additionally, the available current-carrying capacity limit or the range of current-carrying capacity limits for each of the devices 100A, 100B, and / or 100C can be changed or altered by removing and replacing the trip unit 160( Figure 3 ).

[0098] Thus, the devices 100A, 100B, and / or 100C can be used with different power systems operating at different voltages and currents to protect electrical loads having different circuit protection requirements. Each current-carrying capacity setting corresponds to a correspondingly different time-current curve or time-current profile to control the operation of the switching device accordingly, thereby allowing the device to be generally used for different applications within the provided range of current-carrying capacity settings. Thus, a significant amount of flexibility is provided to use the same devices 100A, 100B, and 100C to meet the various different circuit protection requirements of various different power systems and electrical loads. Since there are different issues for AC power systems and DC power systems from the perspective of circuit protection and from the perspective of hazardous locations, different versions of the devices 100A, 100B, and 100C for AC systems and DC systems are envisioned.

[0099] In Figure 4 the example, the devices 100A, 100B, and 100C are mounted on a distribution board, and thus each device is connected via the bus structure of the distribution board to the same line-side circuit 132 that can operate at a given voltage and current during normal operation. The electrical loads 170, 172, and 174 are protected by the devices 100A, 100B, and 100C against excessive current flowing to the electrical loads in the event of an abnormal condition in the line-side power circuit 132. For the same type of electrical loads having similar circuit protection requirements, the same current-carrying capacity setting (e.g., 100A) will typically be used on each of the devices 100A, 100B, and 100C.

[0100] In other embodiments that may or may not involve a switchboard, one or more of devices 100A, 100B, and / or 100C may alternatively be connected to different line-side circuits that may operate at different voltages and currents during normal operation, such that devices 100A, 100B, and 100C may operate at different current-carrying capacity settings, respectively. The adjustable settings of devices 100A, 100B, and 100C still allow them to accommodate some variations in the line-side and load-side circuits while still effectively providing the desired circuit protection.

[0101] However, actually achieving the desired circuit protection depends on whether the wiring used to make the line-side and / or load-side connections is compatible with the user-selected current-carrying capacity settings of devices 100A, 100B, and 100C in any given installation. For example, if the current-carrying capacity of the wiring or cable used to make the load-side connection is limited to 50A, and the device is set to 100A, then if current occurs, the current passing through will far exceed the current-carrying capacity limit of the cable. This means that the cable may overheat to an extent that may cause ignition problems and / or malfunctions and generate arcs at the terminals of the device or elsewhere. Therefore, safeguards are provided as described below to detect an inadvertent user input of an incompatible setting for the device that exceeds the corresponding limit of the wiring connected to devices 100A, 100B, 100C.

[0102] Figure 5 is an exemplary flowchart of an exemplary process algorithm 200 for ensuring device limit setting and wiring limit compatibility and for intelligently implementing the fail-safe measures of circuit protection devices 100A, 100B, and 100C ( Figure 4 ) in view of device settings that conflict with the in-place wiring. Algorithm 200 may be implemented by a processor 150 ( Figure 3 ) of device 100 and / or via a processor-based remote device such as processor-based remote device 178 ( Figure 4 ) that communicates with the processor 150 of each device. Algorithm 200 may be executed device-by-device at the specific installation site of each of devices 100A, 100B, and 100C.

[0103] At step 202, a device setting (e.g., a current-carrying capacity setting) is received at one of devices 100A, 100B, and 100C. The device setting may be input by the user in any of the above ways or other ways known in the art, and after being input, the device setting is correspondingly received by the processor 150 or remote device 178 of the corresponding device for which it was input for evaluation of wiring compatibility as described below.

[0104] In step 204, for the device location and the wiring used to connect the device to the power system, wiring ampacity limits are also accepted. Wiring ampacity limits are typically related to the wire gauge of the line-side wiring or the load-side wiring. The wire gauge reflects a measurement of the wire diameter and the cross-sectional area through which current is conducted, and the conducted current is in turn related to the amount of current that the wire can safely carry over a specified duration, as well as its resistance and weight. Thus, a wire with a larger diameter can carry a greater amount of current than a wire with a smaller diameter. The wire length and other factors specific to a particular installation may also affect the wiring limits and should be considered.

[0105] For the purposes of this discussion, the wiring ampacity limit represents the maximum or peak current load that the wiring can withstand over a predetermined amount of time before being heated to the point of structural failure. The wiring ampacity limit for any particular wire can be determined theoretically or empirically and, in most cases, can be inferred from the wire gauge. The wiring ampacity limit can be specified during the initial design and construction of a new power system and entered into device 100 when the power system is initially wired and completed by the device. Similarly, the wiring ampacity limit can be known from construction blueprints or other records and entered into device 100 accordingly.

[0106] In some contemplated embodiments, the wiring ampacity limit can be an initial user input parameter required by device 100 before allowing the user to select one of the desired ampere settings. For example, when device 100 is connected, the user can be prompted via a local or remote user interface to identify the wire material (e.g., copper or aluminum) and the ampacity limit. Device 100 can also have a built-in NEC wiring ampacity chart (i.e., an ampacity chart stored in the device's memory) for the user to reference for desired device input or for the device to reference later to ensure that the device ampacity setting cannot be selected to be higher than the applicable wiring limit.

[0107] In the case where the wiring is exposed, the wiring ampacity limit can be known by inspecting it and entered by the user into device 100 without reference to materials, charts, or other information provided via device 100. In other cases, the wiring ampacity limit may be unknown or not easily determinable, and thus such step 204 can be optional and not required to be performed.

[0108] At step 206, the wiring ampacity limit can also be determined via the sensing, inferring, and calculating techniques described below. The determination at step 206 can include determining the wiring ampacity limit at each of the line-side terminals and the load-side terminals. When evaluating the line-side connection and the load-side connection, certain issues that are important for operating device 100 in a hazardous location can be detected. Specifically, any differences in the wiring limits of the line-side and load-side wiring should be considered, whether intentional or unintentional during the installation of the power system, and the lower limit should be used to avoid the risk of ignition in the hazardous location.

[0109] For example, if it is found that the load side wiring has a greater current-carrying capacity limit than the line side wiring, the settings of the device 100 should be evaluated based on the smaller limit of the line side wiring rather than the larger limit of the load side wiring. For example, if the limit of the line side wiring is 50A and the limit of the load side wiring is 100A, a device setting of 100A will allow current to flow at a level higher than the 50A limit, which is not a problem for the load side wiring but poses a risk of overheating and related ignition risk to the line side wiring, which should be avoided in a hazardous environment. In this case, the device 100 should only operate at a 50A setting.

[0110] Similarly, if the limit of the load side wiring is 50A and the limit of the line side wiring is 100A, a device setting of 100A will allow current to flow at a level higher than the 50A limit, which is not a problem for the line side wiring but poses an ignition risk to the load side wiring, which should be avoided in a hazardous environment. Although the line side wiring and the load side wiring may be expected to have the same current-carrying capacity limit in many applications, this can be confirmed at step 206 and false assumptions can be avoided in cases where the line side wiring and the load side wiring have different wiring limits.

[0111] In addition, since the wiring current-carrying capacity limit can be affected by temperature, at step 208, temperature input can be received from one or more temperature sensors in the device 100 and / or from another temperature sensor external to the device 100. Therefore, when the ambient temperature in the location of the corresponding device 100 increases, the wiring current-carrying capacity limit determined or accepted from steps 204 and 206 can be adjusted. Specifically, when the ambient temperature rises, the wiring limit should be adjusted downward because the thermal effects of the surrounding environment and the thermal effects from the current are cumulative in the wiring. Therefore, for any given wire, the wiring current-carrying capacity limit may actually be reached at different current levels depending on whether the surrounding environment is hot or cold. For example, a wiring with a current-carrying capacity limit of 100A before temperature adjustment may have a current-carrying capacity limit of 80A after temperature adjustment. This means that when operating under elevated ambient temperature conditions, the device 100 set to 100A can still transfer 80A to 100A of current to the load side wiring, and although the load side wiring is below the set limit, this can still cause the wire to overheat and pose an ignition problem in a hazardous location.

[0112] When the temperature input at step 208 exceeds a predetermined threshold of the wiring limit determined at step 206, the processor may generate a notice or alert at step 210 to a responsible person or other processor-based device to take corrective measures or intervene appropriately. The notice or alert may include relevant data and explanations of potential hazardous operating conditions that may cause upstream circuit breakers and switches to be actuated (locally or remotely and manually or automatically) to avoid further heating of the wiring due to cumulative thermal effects. The notice or alert generated at step 210 does not need to indicate that the wiring current-carrying capacity limit has caused any specific problem or that there is any overcurrent condition, but rather may be regarded as a marker indicator of an external source generating excessive heat, which indicates an increased risk of wiring overheating and ignition and thus may provide a basis for actively shutting down the power system. If the ambient temperature continues to rise or does not drop within a predetermined time period, the notice or alert is escalated if possible. Optionally, a control feedback loop may be implemented to reduce or limit the current flowing through device 100 until the temperature drops to an acceptable range, or alternatively, all current flowing through device 100 may be disconnected and excluded if a certain temperature threshold is met.

[0113] At step 212, the determined wiring limit is received from another nearby device 100 via, for example, wired or wireless communication, or the determined wiring limit is received from a remote device 178 via wired or wireless communication. At step 214, the wiring limit determined at step 206 is compared with the wiring limit determined from the nearby device at step 212. This comparison provides a basis for determining at step 216 whether there is an error. If the compared limits match or are reasonably consistent, there is no error, and the wiring limit determined at step 214 can be confirmed at step 218. If the limits compared at step 216 are different or in conflict, an error condition occurs, and a notice or alert appears at step 220, enabling appropriate steps to be taken to investigate the possible error. Steps 212 to 218 may be most practical in a switchboard installation where similar loads are known to be connected to similar wiring and the devices can confirm the similar wiring by comparing with each other. In cases where steps 212 to 218 may not be decisive, such as when there is no nearby device 100 or when there are no similar loads and wiring, steps 212 to 218 may be considered optional and can be omitted.

[0114] At step 222, the settings received from the user at step 202 are compared with the settings accepted at step 204 (if applicable) and the determined or confirmed wiring limit of step 206 or 218, including any required adjustments to the temperature at step 208. The multiple different data points provide system redundancy and health-check capabilities to identify faulty devices or other problems that may not be otherwise obvious to the user.

[0115] At step 224, it is determined whether the current-carrying capacity setting received from the user at step 206 exceeds the wiring limit notified by the above inputs of steps 204, 206, and 218. If the received user setting does not exceed the wiring current-carrying capacity limit, the setting is accepted as a valid and safe option for use by device 100. At step 228, the accepted setting is transmitted to other devices 100 and / or to a remote device 178.

[0116] The accepted setting transmitted to other devices can be another basis for comparing and determining error conditions or inconsistencies with respect to the settings of other devices. For example, in a switchboard installation including 24 devices, if 23 of the devices 100 are set to 60A, the received setting of 50A for the 24th device 100 can be marked as potentially incorrect even if it does not exceed the wiring limit. A received setting that is too low can cause unnecessary operation of device 100 by being overly sensitive to current conditions that are actually not a problem from the perspective of circuit protection. Similarly, in a switchboard installation including 24 devices, if 23 of the devices 100 are set to 60A, the received setting of 70A for the last device can be marked as potentially incorrect even if the 70A limit does not exceed the wiring limit. A received setting that is too high can cause device 100 to be insufficiently sensitive to current conditions to meet the demands of a particular load.

[0117] At step 230, the setting accepted at step 226 and received from the user at step 206 is used to select a corresponding time-current curve or time-current profile, and the switching element is operated accordingly to achieve the desired circuit protection according to the selected setting. With the above evaluation, the setting received from the user can be safely applied while ensuring that the wiring does not overheat due to the user setting exceeding the wiring handling capacity and causing a potential ignition source to occur.

[0118] If at step 224 the setting received from the user at step 206 does exceed the wiring current-carrying capacity limit, the received setting is rejected at step 232. At step 234, the user can be prompted to select another setting, and the algorithm returns to step 202 to evaluate the next received setting. Thus, device 100 cannot be used unless a setting compatible with the installed wiring is received. A device setting that is incompatible with the wiring will not be accepted, and the associated ignition risk when used in a hazardous location is avoided.

[0119] As an alternative to steps 232 and 234, if the setting received from the user at step 206 exceeds the wiring current-carrying capacity limit at step 224, the apparatus 100 may enter a fail-safe mode at step 236. In the fail-safe mode, at step 238, the apparatus 100 is controlled at the nearest setting that does not exceed the wiring limit. That is, due to the wiring limit issue, the processor 150 of the apparatus 100 or the remote device 178 may automatically change the 100A setting to an 80A setting, and at step 328, the corresponding time-current curve or time-current profile is selected to operate the switching element accordingly, thereby implementing a fail-safe mode of circuit protection that does not exceed the wiring limit. At step 240, a notification or alarm is issued to reset the received setting (e.g., 100A) to another setting (e.g., 80A) considering the applicable wiring limit to avoid any ignition that might otherwise occur. In these respects, the apparatus 100 is substantially foolproof without resulting in related prompts to reject user input and make another setting selection, which might confuse or frustrate some users attempting to set the apparatus.

[0120] The processor 150 or the remote device 178 may also proactively adopt this fail-safe operating mode in response to ambient temperature input and other considerations. For example, if the ambient temperature rises to a first predetermined threshold, the previously verified 100A setting in the algorithm may be reset to an 80A setting, and if the ambient temperature rises to a second predetermined threshold, it may be reset again to a 60A setting to manage the ignition risk when the conditions in the surrounding environment change. When the setting is reset, notifications and alarms may be generated for user feedback and for coordinated system control with other circuit protectors and devices that control the power system.

[0121] Figure 6 A detection technique for determining the wiring limit of the algorithm 200 ( Figure 5 ) is shown. As Figure 6 shown, the terminal assembly 250 includes a lug terminal 252 and a conductor fastener 254 such as a screw. The lug terminal 252 defines a conductor channel 256 for a single-strand or multi-strand conductor 258 contained within a cable sheath 260. A threaded hole 262 is formed on the upper side of the lug terminal 252. In an exemplary embodiment, the fastener 254 is a screw configured to advance towards and away from the conductor channel 256. After the conductor 258 extends into the conductor channel 256, the fastener 254 is advanced to physically contact and engage the conductor 258 with sufficient clamping force to ensure the desired contact force and a secure electrical connection between the conductor 258 and the terminal lug 252.

[0122] One way to detect the current-carrying capacity of conductor 258 is to detect the position of conductor fastener 254 relative to terminal tab 252 and conductor 258. The position of fastener 254 when engaged to the conductor is a function of the size (e.g., diameter) of electrical conductor 258. Each rotation of the fastener thread advances fastener 254 a known distance toward cable conductor 258. The overall size of conductor channel 256 ([ Figure 6 the vertical dimension in the plane of) in which the threaded shank of fastener 254 can move is fixed in terminal tab 252, so if the distance that the fastener shank extends into conductor channel 256 is known, the size of cable conductor 258 can be calculated by subtracting the distance that the fastener shank extends from the overall size. The size of cable conductor 258 can then be compared to the corresponding sizes of known wire gauges.

[0123] In one embodiment, a position sensor 264 is provided to detect the engagement position of conductor fastener 254 within terminal tab 252 and generate a signal corresponding to the detected position of conductor fastener 254 to processor 150 of device 100 or to another device such as remote device 178 ( Figure 4 ). The engagement position of the fastener can be detected mechanically or electrically, for example, by detecting the number of turns of fastener 254 from a known starting position to its engagement position. The engagement position can also be detected mechanically or electrically after engagement to determine the portion of conductor channel 256 occupied by the fastener. Similarly, in some cases, the cable conductor in question can be detected directly by comparison detection and analysis of conductor channel 256 before and after insertion of the cable conductor 256.

[0124] Processor 150 can calculate or infer the conductor diameter based on the detected number of fastener turns, the engagement position of the fastener, or the detected size of cable conductor 258 and associate each of them with the closest attributes of known wire gauges. A lookup table or other database can then be queried to retrieve the applicable current-carrying capacity limits for the best-matching wire gauge (wire type, temperature rating, material, etc.). In some envisioned examples, it can be assumed that a conductive material (e.g., copper) is used for the connections made in the cable / wiring. However, if there can be wires or cables with different conductor materials (e.g., aluminum), additional lookup tables and inputs or determinations can be implemented. In some cases where the routing of the wiring (e.g., length) is known or can be calculated via the voltage drop sensed at both ends of the connection, the system can recommend a wiring upgrade to improve the wiring performance.

[0125] In some embodiments, detecting the fastener position can also detect loose terminal connections, whether initially or over time due to changes in the position of fastener 254 in a hazardous location due to vibration or thermal cycling. For example, an initially loose connection can be detected by empirically or theoretically determining a baseline position of fastener 254 and comparing the detected position to the baseline position, which provides optimal clamping and contact forces for each wire gauge. Feedback can be provided to the user on device display 116( Figure 1 ) or otherwise to ensure that a sufficient connection is established. Looseness of fastener 254 can likewise be determined by periodically checking and comparing the detected fastener position to the baseline position. Loose connections should be avoided because they increase resistance and generate heat at the terminals, creating a potential ignition problem. In some cases, device 100 can detect a loose connection via an increase in resistance detected at the corresponding terminals of the device. If needed or as required, switch elements in device 100 can be operated to limit current until the loose terminal connection can be corrected.

[0126] In some embodiments, the terminal including the fastener can include a positive indication feature for reference by the user or device 100, which aids in a consistent assessment of the position of the wire relative to the fastener (or vice versa).

[0127] In some cases, the terminal lug can include different locations for the wire to be inserted, which should be considered when attempting to infer the wire gauge from the fastener position, because inserting the wire at different locations can cause the fastener to terminate at different positions when tightened. To accommodate this possibility of variation, in some cases, the user can input the number of turns of the fastener (starting from a predetermined starting position), or input which specific location in the lug the wire is being inserted into, to facilitate detection of the wire gauge and corresponding wiring limitations.

[0128] In additional and / or alternative embodiments, additional inputs regarding different wire types (e.g., solid wire versus stranded wire) can utilize appropriate compensation in the algorithm to account for the different wire types, thereby consistently determining the wiring limitations.

[0129] In some embodiments, an optical sensor or the like can be included in device 100, allowing the device control to automatically detect and distinguish wiring and terminal variations.

[0130] In embodiments where the allowable wire types are specified to exclude other possibilities, a simplified algorithm is possible without detailed user input of the wiring type and attributes as described above.

[0131] In additional embodiments, the devices 100 can communicate with each other and compare, for example, the resistance in a wired connection between the respective devices with inputs such as wire type, length, etc. If the determined resistance related to the operating temperature is within an acceptable range, the safe operation of the electrical system can be confirmed. However, if the determined resistance exceeds a predetermined threshold, appropriate measures and actions can be taken in response, including those described above.

[0132] Although exemplary techniques for determining the wiring current-carrying capacity limit have been described, other techniques are possible in additional and / or alternative embodiments of the devices and systems.

[0133] Figure 7 A power sensor feedback system is shown that includes circuit protectors 100A, 100B, 100C, and 100D, a remote device 178 (also shown in Figure 4 ), and a power system feedback sensor 180 external to the device. The devices 100A, 100B, 100C, and 100D each communicate with each other, communicate with the remote device 178, and communicate directly or indirectly with the power system feedback sensor 180, and provide an extended sensor system or network that can further allow the detection and control of conditions that, if unresolved, may pose a risk of ignition.

[0134] Each of the devices 100A, 100B, 100C, and 100D is an intelligent device that includes complex sensing and evaluation capabilities regarding a specific installation point in the power system as described above. In combination with the power system feedback sensor 180, the intelligence of the devices 100A, 100B, 100C, and 100D (regarding the larger power system to which they are connected) can be further enhanced, thereby conferring further functionality with substantial benefits to the system operator and even further enhancing the operational safety in a hazardous environment.

[0135] For example, the devices 100A, 100B, 100C, and 100D provide feedback loops to each other and to the power system feedback sensor 180 that can be analyzed by the remote device or by the devices 100A, 100B, 100C, and 100D themselves to more effectively regulate the operating power system while actively managing the surface temperatures of the devices 100A, 100B, 100C, and 100D and the associated wiring and other devices in the power system other than the devices 100A, 100B, 100C, and 100D.

[0136] For example, the power system feedback sensor 180 may include a temperature sensor for the ambient environment and for the operating temperature of components other than the devices 100A, 100B, 100C, and 100D at locations outside the locations where the devices 100A, 100B, 100C, and 100D are located. The detected temperature from the power system feedback sensor 180 may be compared with the temperatures detected by the devices 100A, 100B, 100C, and 100D, and may also be compared with a predetermined standard. Health checks and error conditions may be detected, and notifications and alerts may be generated. Devices upstream and downstream of each other in the power system may communicate and compare the detected temperatures, and may take proactive steps to operate switches and active circuit protectors, including but not limited to the devices 100A, 100B, 100C, and 100D in response to the detected conditions. For example, even if the devices 100A, 100B, 100C, and 100D do not detect an excessive ambient temperature, a high ambient temperature detected downstream may cause one or more of the devices 100A, 100B, 100C, and 100D to limit the current flowing to downstream devices. Similarly, the remote device 178 may operate devices other than the devices 100A, 100B, 100C, and 100D to mitigate problems that may not be detected at the locations of those devices.

[0137] In another example, the tripping of an upstream or downstream circuit protector may indicate an electrical problem (excessive overload or short circuit condition) that is not detected at the locations of the devices 100A, 100B, 100C, and 100D but can be mitigated via the operation of the devices 100A, 100B, 100C, and 100D to limit the current to a specific location. The collective feedback data provided and available may be used to diagnose problems in the power system and the sources of these problems at specific locations. Comparison of the temperature data of devices in close proximity to each other may reveal loose terminal connections operating at relatively high temperatures, which cannot be explained by ambient temperature differences or actual operating current conditions.

[0138] The devices 100A, 100B, 100C, and 100D and / or other devices in the power system feedback sensor 180 may implement infrared sensing to determine the thermal signature at the terminals of each device, providing confirmation of the correct operation of the power system or clues to power system problems that need to be diagnosed. Such problems may include loose connections that result in increased resistance and elevated operating temperatures. A predetermined baseline for comparison may be stored and used to detect loose terminal connections, over-sized or under-sized wiring, overload conditions, etc.

[0139] Devices 100A, 100B, 100C, and 100D in the power system feedback sensor 180 and / or other devices may also include an arc fault circuit interrupter (AFCI) component or a ground fault circuit interrupter (GFCI) component. Arc characteristics may be detected and / or the operation of such components may assist in diagnosing power system operation, points of problems, and / or explaining circuit protector tripping events at specific locations in the system. In terms of arc discharges that may be caused by loose terminal connections, such components can detect and identify them while providing enhanced circuit protection and avoiding or suppressing the arc discharge to a level below that sufficient to cause ignition problems.

[0140] The detection and sensing of various parameters of devices 100A, 100B, 100C, and 100D in the power system feedback sensor 180 and / or other devices, taken together, provide system redundancy to effectively diagnose problems or resolve ambiguities that might otherwise exist.

[0141] For example, a terminal that is hotter than expected compared to other similarly located terminals may indicate a loose connection as described above. Detection of the terminal fastener position can positively or negatively confirm whether the connection is actually loose, thus eliminating false positives in identifying loose terminals. If the terminal is not loose but is getting hot, the voltage sensor and current sensor can positively or negatively confirm whether an overcurrent explains the terminal temperature. If there is no overcurrent, the terminal temperature may be elevated due to incompatible device settings, which can be evaluated as described above. If the device settings are incompatible, there may be an error in the wiring current-carrying capacity limit, which can be confirmed by voltage and current readings from other devices. Such analysis can be repeated until a conclusion is reached. If the system cannot reach a conclusion, it can send a notification or alert, including the data that has been examined to include or exclude possible diagnoses.

[0142] The analysis and diagnosis can be reported and archived to provide valuable insights into the operation of devices 100A, 100B, 100C, and 100D and the remote device 178, and / or insights into the operation of the power system over time, for troubleshooting and diagnostic purposes. When diagnosing an event, devices 100A, 100B, 100C, and 100D and / or the remote device 178 that communicate with the sensors can also learn over time so that the system becomes more effective and reliable in correctly inferring the operating conditions without having to consider all possibilities in detail.

[0143] Devices 100A, 100B, 100C can also sense things such as phase-to-phase short circuits or phase-to-ground short circuits, individually and in combination. For example, if a maintenance person leaves a screwdriver in a way that grounds one phase or shorts another phase after a maintenance event, the sensors and intelligence in device 100 can detect such a condition and prevent the device from being powered on and any resulting arc discharge event.

[0144] On the other hand, the intelligent sensing in devices 100A, 100B, and 100C can individually and combinatorially identify a phase loss or phase imbalance in the power system, as well as human errors in device connections. For example, if a three-pole device is only installed on two poles of the power system, devices 100A, 100B, or 100C can detect this condition and prevent the corresponding device from being powered on until all connections are correctly completed. Another example is that intelligent sensing can be used to distinguish a phase loss condition (e.g., when only two of the three phases of a correctly connected three-phase power supply are present) from other conditions (e.g., the aforementioned error in connecting the third phase).

[0145] On the other hand, devices 100A, 100B, and 100C can individually and combinatorially sense the state or condition related to the device housing to ensure that certain requirements are met in order to power on the device or remotely change its state. For example, devices 100A, 100B, and 100C can include peripheral sensors that provide feedback to the equipment to ensure that bystander personnel are safely positioned relative to one or more of devices 100A, 100B, and 100C before devices 100A, 100B, or 100C are locally or remotely operated.

[0146] On the other hand, the intelligent sensing within devices 100A, 100B, and 100C can be extended to the structural condition of each device 100A, 100B, or 100C in use. For example, devices 100A, 100B, and 100C can include strain gauges, accelerometers, pressure sensors, chemical sensors, etc., all of which can be used to monitor the environmental and / or structural integrity of devices 100A, 100B, and 100C that provide hazard protection, thereby ensuring that devices 100A, 100B, and 100C remain in good compliance with regulatory standards after initial installation.

[0147] Figure 8 is a perspective view of a compliant hazardous location circuit protection device 300 according to a third exemplary embodiment of the present invention. The circuit protection device 300 includes the housing 102 described above, and the described housing 102 has the chemical resistance, impact resistance, and thermal management features described above with respect to device 100, but omits the digital display 116 of device 100( Figure 1 ). As Figure 8 shown, the user can reach the toggle switch 302 on the upper surface of the housing 102 to manually activate the device 300 between the "on" and "off" states, thereby connecting and disconnecting the load side and the line side of the device 300. In other embodiments, a manual actuator other than the toggle switch can be employed. In some cases, a display 116 can be provided in addition to or in place of the toggle switch 302 or another manual actuator.

[0148] Similar to device 100, device 300 can interconnect a line-side circuit or a power supply circuit with an electrical load operating via alternating current (AC) or direct current (DC). Device 300, as shown, is configured as a circuit breaker and thus provides automatic circuit protection in response to a predetermined overcurrent condition, which can be selected by the user within a specific range and input to the device via a local or remote user interface, or otherwise pre-programmed into the device. Device 300 can operate according to a specified time-current curve or time-current profile suitable for providing adequate protection for the connected load.

[0149] Figure 9 is a simplified schematic diagram of circuit protection device 130 in an exemplary hybrid configuration. Device 300 includes input terminals 130a, 130b, 130c, each of which is connected via a connecting cable or conduit to one phase of a three-phase power supply indicated as line-side circuit 132. Device 300 also includes output terminals 134a, 134b, 136c, each of which is connected to a load-side circuit 136, such as motors, fans, lighting fixtures, and other electrical equipment in an industrial facility, where flammable gases, vapors, or substances can be airborne as indicated at 138, creating an explosive environment.

[0150] Between each pair of the input terminals 130a, 130b, and 130c and the output terminals 134a, 134b, and 136c are mechanical circuit breakers 304a, 304b, and 304c and solid-state switching devices connected in parallel, the arrangement of which is shown as 140a, 140b, and 140c. Exemplary solid-state switch arrangements 140a, 140b, and 140c include pairs of insulated gate bipolar transistors (IGBTs) connected in series, where, as described above, each pair includes a varistor element connected in parallel to the IGBT. Although exemplary solid-state switch arrangements are shown and described, other arrangements may also achieve the solid-state switching function in an arc-free manner. As described above, the solid-state switching devices operate in an arc-free manner, and thus, in terms of arc discharge, the solid-state switching devices themselves do not pose an ignition risk in a hazardous location.

[0151] The combination of mechanical circuit breakers 304a, 304b, and 304c with solid-state switch arrangements 140a, 140b, and 140c can improve the response time of device 300 relative to device 100. However, mechanical circuit breakers 304a, 304, 304c operate with mechanical switch contacts, so special attention is required for applications in hazardous locations because arc discharges can be an ignition source. Solid-state switch arrangements 140a, 140b, and 140c connected in parallel to mechanical circuit breakers 304a, 304b, and 304c can limit the current in mechanical circuit breakers 304a, 304, and 304c during an overload or short-circuit event to reduce the intensity of any resulting arc to a level below that required to cause ignition problems or otherwise eliminate arc discharges altogether.

[0152] Device 300 is also connected to electrical ground 146 to dissipate any charge on the housing surface as described above, thereby eliminating possible ignition sources via electrostatic discharge as described above. Line-side and load-side connections can be established using any of the safety terminal assemblies described above (including but not limited to armored cables and cable glands) to provide enhanced safety assurance for explosive environments.

[0153] In the envisioned embodiments, housing 102 of device 300 can be made of metal or non-metallic materials. In some cases involving certain metal or non-metallic materials, the housing material, filling material, and encapsulation material must be strategically selected to address electrostatic issues. Combinations of conductive and non-conductive materials can be utilized inside and outside device 300 to appropriately provide a path to electrical ground.

[0154] Figure 10 is a block diagram of circuit protection device 300 which, in addition to the above-described elements in device 100, further includes a control input for manual actuator 302 and a trip actuator 310 which operates a mechanical circuit breaker 312 including a mechanical switch. When a predetermined overcurrent condition occurs, trip unit 160 causes trip actuator 310 to shift the movable switch contacts and open the circuit through device 300. The trip actuator can be an electromagnetic member, such as a solenoid, which can simultaneously shift the switch contacts of each mechanical circuit breaker disposed in device 300, where solid-state switch arrangements 140a, 140b, and 140c limit the current when the switch contacts are shifted. Thereafter, manual actuator 302 can be used to reset device 300 by closing the mechanical switch.

[0155] Although an exemplary device architecture of device 300 has been described, it should be understood that Figure 10 certain of the elements shown can be considered optional for providing more basic functionality, and additional elements can be added to make the operation of device 300 more complete and intelligent.

[0156] Figure 11 Schematically shows Figures 8 to 10 the thermal management features of the circuit protection device shown. Although as described above, the hybrid device 300 can operate in an arcless manner in many cases, since arc discharges can depend on the nature of the electrical fault and the voltage and current of the power system operating when the electrical fault occurs, additional considerations for addressing any arc discharges that occur must be taken into account.

[0157] As Figure 11 shown, in addition to the thermal management features described above for device 100, device 300 also includes additional features to ensure that any arc discharges that occur during the operation of the mechanical circuit breaker are isolated from the surrounding environment or otherwise reduced to a level that is insufficient to cause ignition in an explosive location. Figure 11 The housing 102 of device 300 is shown, which defines a first or primary enclosure 320 and a series of secondary enclosures 322a, 322b, and 322c. The secondary enclosures 322 are used to contain any arcs within the secondary enclosures while ensuring that airborne ignitable gases, vapors, or substances cannot reach the secondary enclosures 322a, 322b, and 322c and thus cannot be ignited by the operation of the mechanical circuit breaker.

[0158] In the envisioned embodiment, the secondary enclosures 322a, 322b, and 322c can be hermetically sealed chambers that include respective switch contacts. The hermetically sealed chambers 322a, 322b, and 322c are fluid-impermeable such that any ignitable elements that can penetrate the housing 102 into the hazardous location of the primary enclosure 102 cannot enter the sealed chambers 322a, 322b, and 322c. The hermetically sealed chambers can also be vacuum chambers or filled with an inert gas, such that even if arc discharges are not completely avoided when the switch contacts open and close, the intensity and duration of the arc discharges will be reduced. Each of the secondary enclosures 322a, 322b, and 322c can be provided with additional insulators and materials to control any heat associated with the arc discharge and localize it to the secondary enclosures 322a, 322b, and 322c within the larger enclosure 320. The enclosure within the enclosure construction of the housing 102 houses the other thermal management features described above while addressing the additional issues of mechanical switch contacts in an explosive environment.

[0159] The secondary housings 322a, 322b, and 322c can be made of a material different from the rest of the housing 102, or can be made of a combination of materials that can be the same as or different from the rest of the housing. For example, a metallic material and plastic can be used to construct the chamber, while the primary housing and the rest of the housing can be entirely plastic. There can be many variations in this regard. The secondary housings 322a, 322b, and 322c can be prefabricated and assembled with the housing 102 in a separate manufacturing stage. The secondary housings 322a, 322b, and 322c can enclose some or all of the mechanical circuit breaker mechanism without impeding the movement path of the switch contacts or their ability to move.

[0160] Each of the devices 100 or 300 can be safely used in Division 1 or Division 2 of the IEC and Class I, Division 1 hazardous locations of the NEC without a conventional, separately provided explosion-proof enclosure, and the enhanced safety features regarding wiring limitations and fail-safe operation and intelligent diagnosis and management of problems as described above with respect to the device 100 also apply to the device 300. The above-described built-in ignition prevention features eliminate ignition sources or reduce them to levels insufficient to cause ignition. Thus, the devices 100 or 300 are sometimes referred to as being ignition-proof and thus eliminate any need for a separately provided explosion-proof enclosure. Thus, the devices 100 and 300 prevent a possible explosion that would be safely controlled by setting up a conventional explosion-proof enclosure. Thus, the devices 100 and 300 can be safely operated in explosive locations and eliminate the cost and burden of a conventional explosion-proof enclosure while saving space in the power system.

[0161] Figure 12 An exemplary distribution board 400 including a compliant hazardous location circuit protection device is shown. The circuit protection device includes an array of devices 402, 404 arranged in two columns of devices. The devices 402, 404 in each column include the above-described devices 100 or 300, and the devices 402, 404 can be represented by different ratings, and the different ratings provide different degrees of circuit protection for the various different loads served by the distribution board and its various branches. The distribution board 400 typically includes its own enclosure, but due to the described ignition-proof devices used on the distribution board, the enclosure of the distribution board itself can be a standard enclosure not designed to be explosion-proof. Since the devices 402, 404 are ignition-proof, they can be present in the distribution board enclosure without a conventional explosion-proof enclosure in the distribution board enclosure. The distribution board enclosure protects the devices 402, 404 from environmental conditions, but the distribution board enclosure does not need to be explosion-proof because the devices 402, 404 are ignition-proof. Considering that a known distribution board can accommodate up to 84 devices, eliminating separately provided individual explosion-proof enclosures and common explosion-proof enclosures significantly reduces the operating cost of the devices 402, 404 in hazardous locations. For a large power system including multiple distribution boards located at different positions, the cost is even further multiplied.

[0162] In such switchboard installations that include multiple devices 402, 404 operating simultaneously and in close proximity to each other, the thermal management issues multiply. Thermal effects can accumulate, and adjacent devices can be hotter (i.e., have higher surface temperatures) when operating than when they are used individually or at least spaced farther apart from each other. When heat rises from the lower devices 402, 404, the devices 402, 404 in the upper part of the column can operate hotter than the devices 402, 404 in the lower part of the present disclosure. Then, in some cases, active cooling features and systems may be desirable to avoid undesired temperature effects on the operation of some of the devices 402, 404 or to address elevated surface temperatures. As described above, an active cooling system can be provided on or relative to the switchboard to cool the devices 402, 404 at the system level rather than cooling the devices 402, 404 individually. Variations and combinations of active cooling elements and systems are possible to achieve different cooling effects. The active cooling system can be triggered by ambient temperature sensing, wiring limitations, or an assessment of terminal temperature, as described above.

[0163] Although the switchboard and switchboard enclosure have been described above with respect to the devices 402, 404, similar benefits can be achieved in motor control centers and other locations in the power system where the circuit protection devices 402, 404 are also conventionally located in non-explosion-proof enclosures. Given the sensors and intelligent devices provided in the devices 402, 404 and the motor inrush features provided in the devices 402, 404, additional motor starting components can be integrated into the design of the devices 402, 404, and a combined circuit protector / motor starter can be provided in a single package, as opposed to the conventionally provided circuit protector and motor starter components that are separately packaged and connected in series, each of which requires an explosion-proof enclosure for a hazardous location. In this case, the motor circuit protection can be automatically programmed based on inputs of the motor rating (FLA or possibly just the model, which will provide, for example, the FLA) and wire size.

[0164] Although the combined circuit protector / motor starter has been described, other dual-purpose or dual-function devices 402, 404 are equally possible, which further reduce the cost of installing and maintaining the power system by reducing the number of devices that need to be acquired, installed, and repaired in the power system.

[0165] Figure 13Exemplary waveforms are shown that illustrate the power voltage and current waveform characteristics of various different electrical loads detected and managed by an arc - free circuit protection device compliant for use in hazardous locations, such as the devices 100 and 300 described above. Such current signature detection and management can be implemented algorithmically in the control of the device 100 or 300 to complement the features described above regarding detection of wiring limitations, etc., and to provide further ability to proactively manage risks in the operation of the power system in a hazardous environment.

[0166] At Figure 13 the top, a voltage input curve 510 is shown, which represents the power supply or line - side circuit connected to the line - side terminals of the device 100 or 300. The curve 510 can be identified as corresponding to an alternating - current (AC) power supply. In the absence of a predetermined over - current condition, the device 100 or 300 conducts current to the load connected to the load - side terminals of the device 100 or 300. However, different loads connected to the same device 100 or 300 draw different currents that can be distinguished from one another.

[0167] For example, waveform 520 represents the exemplary current consumption of an energy - saving light bulb that can be protected by the device 100 or 300, while waveform 530 represents the exemplary current consumption of a fluorescent lamp with a conventional ballast that can be protected by the device 100 or 300, and waveform 540 represents the exemplary current consumption of a fluorescent lamp with an electronic ballast. Waveforms 520, 530, and 540 are significantly different from one another, providing the device 100 or 300 with the ability to identify a specific type of load and changes in the load over time.

[0168] As a further example, waveforms 550 and 560 represent the exemplary current consumption of a laser printer in the standby state and during actual operation to print a document. Waveforms 550 and 560 are significantly different from one another, thus providing the device 100 or 300 with the ability to identify the state of the connected load (e.g., standby or non - standby) and changes in the current consumption associated with the state of the load over time. It can also be seen that waveforms 550 and 560 are significantly different from waveforms 520, 530, and 540.

[0169] The exemplary waveform 570 is the sum of waveforms 520, 530, 540, 550, and 560. Thus, waveform 570 represents multiple loads that are protected by the device 100 or 300 and that simultaneously draw current from the power input voltage 510. It can be seen that waveform 570 is significantly different from the individual waveforms 520, 530, 540, 550, and 560, thus providing the device 100 or 300 with the ability to monitor load operation and detect changes in load operation over time. Such differences in the waveforms (individually or collectively) present unique identification features that allow the device 100 to intelligently self - configure itself for optimal operation with the connected loads.

[0170] For example, detection of the unique current signature of a connected load can inform the device 100 or 300 of the start-up current associated with a start event, and the device 100 or 300 can accordingly self-select an operating mode that provides the desired circuit protection while withstanding the start-up current of the connected load. The unique signature can be input into the device 100 or 300 locally or remotely or via initial programming of the device controls to allow such automatic self-configuration of the device when the detected load is connected.

[0171] Such self-configurability can be desirable for portable power applications where the device 100 or 300 can be fixed, but the connected load can vary over time. In the envisioned example, a lighting element can be temporarily connected to the device 100 or 300, and after the lighting element is no longer connected, another load such as a motor or a piece of welding equipment can be temporarily connected to the device 100 or 300. In each case, the device 100 or 300 can automatically adjust its time-current characteristics to optimize its use with the detected load. Additionally or alternatively, input selection can be made locally or remotely to set the device 100 or 300 to a desired setting for the load, and the intelligent device 100 or 300 can compare any input setting to the detected characteristics of the load that the device 100 or 300 can independently verify and confirm. Thus, error conditions can be detected and managed for any incompatibility between the manually selected device settings and the connected load. Management of the detected error condition can include rejecting the user-selected setting, generating a notification or alert, or the device 100 or 300 reverting to fail-safe measures by limiting current or taking other desired measures to ensure safety in a hazardous location.

[0172] Differences in the current waveforms and signatures of the load (individually or collectively) that can be detected in the devices 100 and 300 further allow enhanced intelligence and ability to monitor the larger electrical system to which the device 100 or 300 is connected. Insofar as changes in the detected unique current signature may deviate from the normal expected signature of the connected load, the device 100 or 300 can initiate proactive measures to avoid adverse consequences.

[0173] For example, such proactive measures that can be implemented through algorithms in the control of device 100 or 300 may include, but are not limited to, generating notifications or alerts to responsible personnel to investigate possible problems with the connected load, restricting the current flowing through device 100 or 300 to reduce the ignition risk in a hazardous location by overheating one or more loads, completely stopping the current flowing through device 100 or 300, and transmitting or messaging the detected problem to upstream or downstream circuit protection devices (which may include additional devices 100 or 300) so that the upstream or downstream devices themselves can take proactive or corrective measures. Intelligent devices upstream and downstream of a particular device 100 or 300 can also confirm that the operating temperature and other parameters of concern of the load are below the corresponding safety limits of the hazardous location, and notifications and alerts can be escalated or de-escalated as needed.

[0174] In addition, error conditions can be identified via communication between intelligent devices 100 and 300. For example, in the case of serially connected devices 100 or 300, if the upstream device indicates a problematic load-side characteristic while the downstream device does not, it can be inferred that one of the two serially connected devices has failed, and a notification or alert can be generated to investigate and take corrective measures. Confirmation by the upstream and downstream devices of the detected condition can confirm the correct operation of each device, while differences can reveal error conditions that may not be obvious to the power system supervisor otherwise. Thus, in addition to larger electrical systems, current feature detection and monitoring, as well as comparison of detected features with features made by other devices, can be intelligently used as a health check assessment of device 100 or 300 itself to ensure the safe operation of the power system in a hazardous location. Cascade emergency shutdown procedures are possible, with the ability to give prior warnings to manage the risks of a hazardous location.

[0175] Figure 14 An exemplary change in the current feature in the protected load circuit of device 100 or 300 is shown, which can be detected and managed for more benefits. Specifically, Figure 14 A first waveform 600 and a second waveform 602 over a period of time are shown. As the load operates over time, the current feature can change as components in some loads (such as pumps or motors) tend to mechanically and electrically wear out during the operating life of the load. Thus, device 100 or 300 that detects a predetermined amount of change can initiate a notification or alert to power system personnel prior to a possible equipment failure at the end of the service life. Thus, considering the monitoring and intelligent capabilities of device 100 or 300, it is possible to proactively manage the power system to manage the ignition risk in a hazardous location and avoid unexpected interruptions and system downtime due to predictable events.

[0176] Additionally, an unexpected change in the detected load can provide proactive management or response to user errors when connecting the load to device 100 or 300. For example, in the portable power application scenario described above, a user may inadvertently connect a device or load that is incompatible with or not approved for use with device 100 or 300. Then, device 100 or 300 can take a fail-safe operating mode or shutdown procedure to avoid adverse consequences, as well as provide a notification or alert so that the incompatible or unapproved device can be removed.

[0177] Solid-state or hybrid devices (such as those described above) can be constructed using a variety of different solid-state switching elements, arrangements of solid-state switching elements, and are also implemented in a variety of different power electronics device topologies. A variety of different embodiments are envisioned, involving different degrees of on-state loss, tendency for arcing during operation, conduction loss, component count, relative complexity, ability to meet specific response time characteristics, simplicity or complexity of the operating algorithm, and ability to integrate motor soft start or other features when needed. The solid-state switching elements can be connected in series or in parallel using a modular arrangement to achieve the desired rated voltage scaling or the desired rated current scaling. In terms of desiring to implement a bypass contact, the encapsulation material and thermal management features provided for the bypass contact may be desirable.

[0178] Any of the solid-state switch arrangements and hybrid switch arrangements shown and described above can include or be connected to a line-side electrical fuse to enhance circuit protection reliability by addressing any deficiencies of the solid-state switching elements with respect to certain overcurrent conditions, or to improve the response time to certain operating conditions.

[0179] The above-described chemical-resistant and impact-resistant housing construction, arc-free operation, safety terminal assembly, and advanced intelligent and thermal management features can be easily applied to implement a circuit protection device that is not a circuit breaker device but is still ignition-proof for use in Division 1 or Division 2 hazardous locations of the NEC and Zone 1 or Zone 2 locations of the IEC without a separate explosion-proof enclosure. For example, a fusible switch-disconnect device was discussed above that includes a mechanical switch combined with a fuse. Applying the described chemical-resistant and impact-resistant housing construction, arc-free switch operation, safety terminal assembly, and thermal management features enables a solid-state fusible switch-disconnect device or a hybrid fusible switch-disconnect device to be easily constructed to have similar beneficial effects but provide different degrees of circuit protection.

[0180] Similarly, the above-described chemically resistant and impact resistant housing construction, arc-free switching operation, safety terminal assembly, and certain intelligent and thermal management features can be readily applied to implement a switching device that does not itself provide circuit protection but is still ignition-proof for use in Class 1 or 2 hazardous locations of the NEC and Zone 1 locations of the IEC without an explosion-proof enclosure. For example, mechanical relay switches and contactors are known that provide an open circuit function but do not have the ability to prevent overcurrent conditions. Applying the described chemically resistant and impact resistant housing construction, arc-free switching operation, safety terminal assembly, and thermal management features enables solid state relay devices or hybrid relay devices and solid state contactor devices or hybrid contactor devices to be readily configured to operate safely in explosive environments and to intelligently detect wiring limitations and loose connections to achieve at least some of the above benefits.

[0181] An ignition-proof device (such as those described) can be provided with any desired number of switch poles, for example including only single-pole devices, two-pole devices, three-pole devices, and four-pole devices, to accommodate the needs of any type of electrical power system (including polyphase power systems and multi-phase power systems), while generally providing the ignition-proof function for Class 1 or 2 of the NEC or Zone 1 or 2 hazardous locations of the IEC.

[0182] Based on the above description, the devices and applicable operating algorithms have been functionally described, and those skilled in the art can thus implement the algorithms via programming of a controller or other processor-based device. Such programming or implementation of the algorithm concepts is considered within the purview of those skilled in the art and will not be further described.

[0183] It is now considered that the beneficial effects and advantages of the inventive concept have been fully shown in accordance with the disclosed exemplary embodiments.

[0184] Embodiments of a configurable and compliant circuit protection system for explosive environments have been disclosed. The system includes: at least one switching device including a housing, a line-side terminal, and a load-side terminal coupled to the housing; a bus structure located within the housing and including at least one solid state switching element capable of operating in an arc-free manner to connect the load-side terminal to the line-side terminal and to disconnect the load-side terminal from the line-side terminal; and a controller configured to: receive a selected one of a plurality of different settings for operating the at least one solid state switching element to protect a connected electrical load; and determine whether the received setting exceeds wiring limitations of the explosive environment; whereby the switching device is compliant for use in the explosive environment without a separately provided explosion-proof enclosure.

[0185] Optionally, the controller is further configured to determine wiring limitations. The controller may also be configured to compare the accepted wiring limitations and the determined wiring limitations. The controller may be configured to determine the wire gauge for connecting to the line side terminal and the load side terminal. The controller is configured to determine the wire gauge based on the position of the fastener that completes the connection to the line side terminal or the load side terminal.

[0186] The controller may be configured to receive a temperature input, and based on this temperature input, the controller is configured to determine whether the wiring limitation has been exceeded. The controller may be configured to operate at least one solid state switch element in response to the temperature input to maintain the surface temperature of the housing at or below the rated temperature of the explosive environment, thereby preventing the housing from becoming an ignition source in the explosive environment.

[0187] The controller may be configured to transmit the accepted settings to at least one other switching device in the network of switching devices. The controller may be configured to identify an error in the wiring connected to the line side terminal or the load side terminal and generate a notification or alarm of the identified error. The controller may be configured to accept the received settings only if the wiring limitation is not exceeded and control the at least one solid state switch element according to the accepted settings. Alternatively, the controller may be configured to reject the received settings when the wiring limitation is exceeded and prompt to select an alternative setting from multiple settings. The controller may be configured to enable a fail-safe mode when the received settings exceed the wiring limitation.

[0188] The controller may be configured to detect the unique current signature of at least one connected load, monitor the change of the unique current signature over time; and generate a notification or alarm based on the monitored change of the unique current signature. The controller may be configured to automatically select one setting from multiple different settings based on the detected unique current signature.

[0189] The at least one switching device may further include at least one mechanical switch contact in a bus structure, wherein the housing includes a sealed inner housing that houses the at least one mechanical switch contact, thereby preventing the switch contact from becoming an ignition source in the explosive environment. The at least one solid state switch element may be encapsulated.

[0190] The at least one switching device may be configured as a solid state circuit breaker or may be configured as a hybrid circuit breaker. The housing may be chemically resistant to the components in the hazardous location.

[0191] The written description uses examples to disclose the invention (including the best mode), and also enables one of ordinary skill in the art to practice the invention, including making and using any device or system and performing any incorporated method. The patentable scope of the invention is defined by the claims, and may include other examples that occur to one of ordinary skill in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that do not differ in substance from the literal language of the claims.

Claims

1. A configurable and compliant circuit protection system for an explosive environment, the system comprising: At least one switching device, said at least one switching device comprising: A housing; A line-side terminal and a load-side terminal coupled to said housing; A bus structure, said bus structure being located in said housing and comprising at least one solid-state switching element, said at least one solid-state switching element being capable of operating in an arcless manner to connect said load-side terminal to said line-side terminal and to disconnect said load-side terminal from said line-side terminal; and A controller, said controller being configured to: Receive a selected setting from a plurality of different settings for operating said at least one solid-state switching element to protect a connected electrical load; Determine the wiring limitations of the explosive environment; Determine the wire gauge for connection to said line-side terminal or load-side terminal based on the position of a fastener that makes the connection to said line-side terminal or said load-side terminal; Determine whether the received setting exceeds the wiring limitations of the explosive environment; Accept the received setting only if it does not exceed the wiring limitations; Control said at least one solid-state switching element according to the accepted setting; Reject the received setting when it exceeds the wiring limitations; and Prompt for selection of an alternative setting from said plurality of settings; Whereby said switching device is compliant for use in said explosive environment without a separately provided explosion-proof enclosure.

2. The configurable and compliant circuit protection system according to claim 1, wherein the controller is further configured to compare the accepted wiring limits and the determined wiring limits.

3. The configurable and compliant circuit protection system according to claim 1, wherein the controller is further configured to accept a temperature input, and based on the temperature input, the controller is configured to determine whether the wiring limit has been exceeded.

4. The configurable and compliant circuit protection system according to claim 3, wherein the controller is further configured to operate the at least one solid-state switching element in response to the temperature input to maintain the surface temperature of the housing at or below the rated temperature of the explosive environment, thereby preventing the housing from becoming an ignition source in the explosive environment.

5. The configurable and compliant circuit protection system according to claim 1, wherein the controller is further configured to transmit the accepted settings to at least one other switching device in a network of switching devices.

6. The configurable and compliant circuit protection system according to claim 1, wherein the controller is further configured to identify an error in the wiring connected to the line-side terminal or the load-side terminal and generate a notification or alarm of the identified error.

7. The configurable and compliant circuit protection system according to claim 1, wherein the controller is further configured to: Enable a fail-safe mode when the received settings exceed the wiring limit.

8. The configurable and compliant circuit protection system according to claim 1, wherein the controller is configured to detect a unique current signature of at least one connected load.

9. The configurable and compliant circuit protection system according to claim 8, wherein the controller is further configured to: monitor changes in the unique current signature over time; and generate a notification or alert based on the monitored changes in the unique current signature.

10. The configurable and compliant circuit protection system according to claim 8, wherein the controller is further configured to automatically select one of the plurality of different settings based on the detected unique current signature.

11. The configurable and compliant circuit protection system according to claim 1, wherein the at least one switching device further includes at least one mechanical switch contact in the bus structure, and the housing includes a sealed inner enclosure that houses the at least one mechanical switch contact, thereby preventing the switch contact from becoming an ignition source in the explosive environment.

12. The configurable and compliant circuit protection system according to claim 1, wherein the at least one solid-state switching element is encapsulated.

13. The configurable and compliant circuit protection system according to claim 1, wherein the at least one switching device is configured as a solid-state circuit breaker.

14. The configurable and compliant circuit protection system according to claim 1, wherein the at least one switching device is configured as a hybrid circuit breaker.

15. The configurable and compliant circuit protection system according to claim 1, wherein the housing is chemically resistant to components in a hazardous location.

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