Residual current device

Abstract

Residual current device (1) with a housing (2) extending along a longitudinal axis (5) in a longitudinal direction (6) from a network-side housing area (7) to a consumer-side housing area (8), wherein a network-side connection (3) for electrical connection to a low-voltage network is arranged in the network-side housing area (7) and a consumer-side connection (4) for electrical connection to one or more electrical consumers is arranged in the consumer-side housing area (8), wherein the residual current device (1) comprises a control unit (15) for detecting fault conditions, wherein at least one status indicator element (10, 10', 10'') controllable by the control unit (15) is arranged on the housing (2) for optical signaling of the presence of a fault condition, characterized in thatthat furthermore, at least one first display means (11) controllable by the control unit (15) and at least one second display means (12) controllable by the control unit (15) are arranged on the housing (2), wherein the control unit (15) is configured to generate an optical signal by means of the at least one first display means (11) when a fault condition due to a network-side fault is detected and to generate an optical signal by means of the at least one second display means (12) when a fault condition due to a consumer-side fault is detected.

Description

AREA OF INVENTION The present invention relates to a residual current device with a housing that extends along a longitudinal axis in a longitudinal direction from a mains-side housing area to a consumer-side housing area, wherein a mains-side connection for electrical connection to a low-voltage network is arranged in the mains-side housing area and a consumer-side connection for electrical connection to one or more electrical consumers is arranged in the consumer-side housing area, wherein the residual current device comprises a control unit for detecting fault conditions, wherein at least one status indicator element controllable by the control unit is arranged on the housing for optical signaling of the presence of a fault condition. STATE OF THE ART Ensuring the safe operation of electrical equipment, especially power tools, during construction and assembly work is a challenge, as faulty electrical installations are a real possibility, particularly on construction sites. To increase the safety of users of electrical equipment, a portable residual current device (sometimes also called a "PRCD") is connected to the low-voltage network provided by the existing electrical installations. The electrical equipment, especially power tools, is then connected to the portable residual current device—and not directly to the low-voltage network. A low-voltage network is defined as an alternating current network with an effective voltage typically between 130 V and 1000 V, and more specifically between 230 V and 400 V. A residual current transformer (RCD) is typically used to detect fault currents in residual current devices (RCDs). The conductors to be monitored, which consist of at least one phase conductor and one neutral conductor, form a primary side with a primary winding of this transformer. Under normal operating conditions, their magnetic effects cancel each other out due to the opposing conductor orientation. Only when a fault current or differential current is present, which preferably flows to earth due to a fault, is a voltage or secondary voltage induced in a secondary winding or on a secondary side of the transformer. If the induced secondary voltage and / or an associated secondary current exceeds predetermined threshold values, this is detected as a fault by the RCD.The lines are then interrupted by the residual current device, preferably by means of switching contacts provided for this purpose and a switching device (e.g. relay). The transformer typically has a core, preferably made of iron or ferrite. The magnetic flux that triggers the tripping mechanism is relatively small compared to the potential magnetization of the core. Depending on the material used, the core material exhibits a more or less pronounced magnetic remanence. Strong magnetization due to a very large differential current, for example, caused by a short circuit between a phase conductor and a protective conductor, can drive the core into saturation. Furthermore, strong magnetization can also be caused by momentary impulse currents occurring during switch-on between at least one phase conductor or the neutral conductor and the protective conductor. Such impulse currents are generated, for example, by Class Y interference suppression capacitors used for radio interference. Due to the strong magnetization, the operating point of the transformer can shift permanently along its remanence characteristic curve.This is also referred to as magnetic hysteresis. In practice, this can lead to a change in the sensitivity, particularly insufficient sensitivity to fault currents or differential currents, of the transformer or residual current device. To avoid such a change in sensitivity, a self-calibrating residual current device and a method for calibrating the residual current device are known from EP 3057190 B1. For this purpose, a test winding is provided with which the residual current transformer can be supplied with a defined test current to simulate a defined differential current. A control unit is provided to drive the test winding to generate the test current and to measure a secondary voltage induced in the secondary winding and / or a secondary current resulting from the induced secondary voltage.If a deviation is detected, a correction factor is calculated to calibrate the residual current device (RCD). This factor is used to multiply the measured voltage values ​​of the secondary voltage caused by differential currents and / or the measured current values ​​of the secondary current caused by differential currents. If the correction factor is greater than a predefined maximum permissible correction factor or less than a predefined minimum permissible correction factor, a calibration error condition is detected. To further enhance safety, it is known to enable the detection of fault conditions not only in the case of differential currents, but also, for example, in the case of fault conditions of the protective conductor of the low-voltage network. Such a fault condition would be a disconnected or interrupted protective conductor (also known as PE conductor). Furthermore, such a fault condition can occur when a voltage exists between the PE conductor and the local earth potential of the user, which can be caused by a fault voltage, in particular a phase voltage, on the PE conductor. A reliable method for detecting such fault conditions is known from EP 3016225 B1. Generally, product standards exist that specify which fault conditions must be detected by compliant residual current devices (RCDs). These product standards are updated periodically, which regularly results in increased requirements for compliant RCDs, which must therefore be able to detect a wide range of different defined fault conditions. In this context, particular reference should be made to the product standards IEC 61540:2023 and EN IEC 61540:2025. In practice, a fault current or a detected fault condition, particularly one of the fault conditions mentioned above, detected by the respective residual current device (RCD) means that an electrical device or appliance connected to the low-voltage network via said RCD cannot be operated. In addition to preventing operation, it is common for the RCD to also provide a visual indication that a fault condition exists. Unfortunately, with known residual current devices (RCDs), especially PRCDs, the user—for example, a tradesperson who has connected a device or power tool to the low-voltage network via the RCD—does not receive a clear indication of the specific fault or its location. Furthermore, poor lighting conditions on construction sites often hinder the rapid and unambiguous identification of visual indicators, particularly when working under time pressure. In practice, this can lead to the user disconnecting the device from the RCD and connecting it directly to the low-voltage network, or—believing that only the device is faulty—connecting a different device directly to the low-voltage network. This can lead to extremely dangerous situations, especially if the identified fault is on the low-voltage network side. TASK OF INVENTION It is therefore an object of the present invention to provide a residual current device that avoids the disadvantages described above. In particular, it aims to provide the user with an improved or simplified way to identify where and in what a detected fault condition lies. PRESENTATION OF THE INVENTION To solve the aforementioned problem, a residual current device (RCD) is provided with a housing that extends along a longitudinal axis in a longitudinal direction from a network-side housing area to a consumer-side housing area, wherein a network-side connection for electrical connection to a low-voltage network is arranged in the network-side housing area and a consumer-side connection for electrical connection to one or more electrical consumers is arranged in the consumer-side housing area, wherein the RCD comprises a control unit for detecting fault conditions, wherein at least one status indicator element controllable by the control unit is arranged on the housing for the optical signaling of the presence of a fault condition, as provided according to the invention.that furthermore, at least one first display means controllable by the control unit and at least one second display means controllable by the control unit are arranged on the housing, wherein the control unit is configured to generate an optical signal by means of the at least one first display means when a fault condition due to a network-side fault is detected, and to generate an optical signal by means of the at least one second display means when a fault condition due to a consumer-side fault is detected. The housing is typically made of an electrically insulating plastic. Particularly when the residual current device is portable, this choice of material can ensure a certain degree of impact resistance and also optimize the feel and aesthetic design. The above statements are clearly to be understood as meaning that the mentioned housing areas belong to the housing or are each part of the housing. The electrical connection to the low-voltage network can be made via a cable that is connected to the network-side connection. The network-side connection has standard, well-known connection devices for this purpose – either reconnectable or non-reconnectable – in particular terminals. Similarly, the electrical connection to at least one electrical device can be made via a cable, one end of which is connected to the device's terminal. The device's terminal can have standard, known connection devices – either reusable or non-reusable – in particular terminals. One or more sockets can be provided at the other end of the cable to connect the devices. The devices can be electrical appliances, especially power tools. Control units for detecting fault conditions are well-known and are used in established residual current devices (RCDs) that can detect fault conditions according to current product standards. The status indicator can sometimes not only show that a fault is present, but also, to a limited extent, provide information about the specific cause of the fault, the specific fault condition, or at least a certain type of fault condition. However, the informative value of the status indicator alone is limited. For example, it may be provided that at least one status indicator element lights up red in the event of a network-side interruption of the PE conductor, flashes green in the event of a loop impedance measurement (see e.g. https: / / de.wikipedia.org / wiki / Schleifenimpedanz) that yields a value greater than a predefined limit, so that there is a risk of an excessively low fault current and thus a tripping that is too slow or not at all, flashes red in the event of a network-side undervoltage, or flashes red in the event of a consumer-side differential current. In this example, it is immediately apparent that, based on at least one status indicator element alone, it is generally not possible for a user to determine whether the respective error is network-side or consumer-side, especially since a red flashing light can occur in both situations. The solution according to the invention, comprising at least one first display means and at least one second display means, provides a remedy here, as the user is immediately informed on which side – on the side of the low-voltage network connection or on the side of the connection of the at least one consumer – the detected fault condition exists. The display means ensure this even under poor lighting conditions, such as those that can occur on construction sites. The signaling with the at least one first display means or with the at least one second display means can take any form, in particular by changing from a non-illuminated state to a permanently illuminated state or to a flashing state (starting from a non-illuminated state or starting from a permanently illuminated state), etc. The user can thus quickly identify on which side a fault detected by the residual current device (RCD) is located. The user can then react accordingly and, for example, disconnect the connected device from the RCD and deliberately discontinue its use if a fault is indicated on the consumer side. In the case of a signaled mains-side fault, the user is warned and can, for example, use a different low-voltage mains connection for the electrical connection to the RCD. To further significantly improve user recognition, a preferred embodiment of the residual current device according to the invention provides that the at least one first indicator is arranged in the mains-side housing area and the at least one second indicator in the consumer-side housing area. As described above, the mains-side and consumer-side housing areas are located opposite each other and define the housing along its longitudinal axis. By arranging the at least one first indicator in the mains-side housing area and the at least one second indicator in the consumer-side housing area, the user can intuitively determine, upon signaling by the respective indicator, on which side the detected fault is located. This is further enhanced by the fact that the first and second indicators are spatially separated from each other.are arranged opposite each other, at least to a certain extent. To further optimize this arrangement of the first and second display means, which promotes user intuition, a particularly preferred embodiment of the residual current device according to the invention provides that the housing has a length measured along its longitudinal axis, and that the mains-side housing area and the load-side housing area each have a length measured along their longitudinal axis that is at most 1 / 3, preferably at most 1 / 4, and particularly preferably at most 1 / 5, of the housing length. Accordingly, a particularly clear spatial separation of the first and second display means can be achieved, as well as—consequently—a particularly clear visual assignment of the at least one first display means to the mains side or the mains-side connection and of the at least one second display means to the load side or the load-side connection. In a preferred embodiment of the residual current device according to the invention, an on / off button is arranged behind the at least one first indicator in the longitudinal direction, and the at least one second indicator is arranged behind the on / off button. The on / off button can be used to activate the residual current device, so that, in a proper operating state (i.e., when the residual current device is connected to the low-voltage network and no fault condition is detected), a connected load is supplied with current.By placing the on / off button between the first and second indicators, the visual separation between them is clarified, further emphasizing the connection between the first and second indicators and the mains side. This, in turn, enhances the user's intuition, allowing them to immediately identify the fault location when a fault is indicated by either the first or second indicator. In a preferred embodiment of the residual current protection device according to the invention, exactly one first indicator and / or exactly one second indicator are provided. This allows for a particularly economical and space-saving implementation of the indicators. At the same time, it ensures unambiguous signaling to the user as to which side a detected fault condition has occurred. In a preferred embodiment of the residual current device according to the invention, the at least one status indicator element is arranged at least partially on the upper surface of the housing, the at least one first indicator means is arranged at least partially on the upper surface of the housing, and the at least one second indicator means is arranged at least partially on the upper surface of the housing. The upper surface of the housing need not be a plane, but points essentially or at least largely in one direction. By arranging at least one status indicator element and the display means on the top of the housing, the user can not only recognize particularly quickly and clearly whether a detected fault condition is on the network side or the consumer side (due to the first and second display means), but also has the opportunity to visually grasp the type of fault, at least roughly (due to the at least one status indicator element). It is conceivable that the at least one status indicator element and / or the at least one first display means and / or the at least one second display means are arranged section by section on another side of the housing, in particular extending to that side. This allows the user to visually detect a signal via the at least one status indicator element and / or the at least one first display means and / or the at least one second display means, even if the user is not looking directly at the top of the housing, but, for example, at an angle to the top of the housing and the other side. In a preferred embodiment of the residual current device according to the invention, the at least one status indicator element comprises at least one light-emitting diode (LED), the at least one first indicator means comprises at least one LED, and the at least one second indicator means comprises at least one LED. This ensures a cost-effective and energy-saving implementation. At the same time, high luminous intensity and thus good visibility of the at least one status indicator element and the indicator means can be guaranteed. Preferably, exactly one light-emitting diode (LED) is provided for the first display means and the second display means, resulting in a particularly cost-effective and energy-saving variant, while still ensuring good visibility of the signaling for the user. Similarly, it is also conceivable that exactly one LED is provided for each status indicator element. The residual current device (RCD) does not need to be permanently installed. Accordingly, in a preferred embodiment of the RCD according to the invention, the RCD is designed as a portable device. As already described, the RCD can therefore be used particularly on construction sites. BRIEF DESCRIPTION OF THE FIGURES The invention will now be explained in more detail using an exemplary embodiment. The drawing is exemplary and is intended to illustrate the inventive concept, but in no way to restrict or even exhaustively represent it. Figure 1 shows a top view of a residual current protection device according to the invention. WAYS TO IMPLEMENT THE INVENTION Fig. 1 shows a top view of an embodiment of a residual current device 1 according to the invention, which is designed as a portable residual current device 1. In the illustrated embodiment, the residual current device 1 has a housing 2 made of electrically insulating plastic, which extends along a longitudinal axis 5 in a longitudinal direction 6 from a mains-side housing area 7 to a consumer-side housing area 8. In the mains-side housing area 7, a mains-side connection 3 (schematically indicated by a dotted square in Fig. 1) is arranged for electrical connection to a low-voltage network, and in the consumer-side housing area 8, a consumer-side connection 4 (also schematically indicated by a dotted square in Fig. 1) is arranged for electrical connection to one or more electrical loads. The electrical connection to the low-voltage network can be made via a cable (not shown) that is connected to the mains-side connection 3. The mains-side connection 3 has conventional, known connection means – reconnectable or non-reconnectable – in particular terminals. For secure fastening and protection of the cable, it is inserted into the housing 2, more precisely into the mains-side housing area 7, via a cable gland 14.Similarly, the electrical connection to at least one electrical load can also be made via a cable (not shown) that is connected at one end to the load-side terminal 4. The load-side terminal 4 can have conventional, known connection devices – reconnectable or non-reconnectable – in particular terminals. One or more sockets can be provided at the other end of the cable to connect the loads. The loads can be electrical devices, in particular power tools. For secure fastening and protection of the cable, it is inserted into the housing 2, more precisely into the load-side housing area 8, via a cable gland 14'. The residual current device 1 comprises a control unit 15 (schematically indicated in Fig. 1 by a dashed rectangle) for detecting fault conditions. In the illustrated embodiment, status indicator elements 10, 10', 10'', which can be controlled by the control unit 15, are arranged on the housing 2 for the visual signaling of the presence of a fault condition. In the illustrated embodiment, each of the status indicator elements 10, 10', 10'' comprises one or more light-emitting diodes. For example, it may be provided that the status indicator elements 10, 10', 10'' - light up red in the event of a mains-side interruption of a protective conductor of the low-voltage network, - flash green in the event of a loop impedance measurement (see e.g. https: / / de.wikipedia.org / wiki / Schleifenimpedanz) that yields a value greater than a predefined limit, so that there is a risk of an excessively low fault current and thus a tripping that is too slow or not at all, - flash red in the event of a mains-side undervoltage or - flash red in the event of a consumer-side differential current. In order to enable a user to identify as quickly as possible on which side – on the side of the mains connection 3 or on the side of the low-voltage network, or on the side of the consumer connection 4 or on the side of at least one consumer – a fault detected by the residual current device 1 is present, the residual current device 1 in the illustrated embodiment further comprises a first indicator in the form of exactly one mains-side light-emitting diode (LED) 11, which can be controlled by the control unit 15, and a second indicator in the form of exactly one consumer-side LED 12, which can be controlled by the control unit 15.The control unit 15 is designed to generate an optical signal via the network-side LED 11 when an error condition is detected due to a network-side fault, and to generate an optical signal via the consumer-side LED 12 when an error condition is detected due to a consumer-side fault. The signaling with the LEDs 11, 12 can be carried out in any predefinable form, in particular by a change from a non-illuminated state to a permanently illuminated state or to a flashing state (starting from a non-illuminated state or starting from a permanently illuminated state) etc. For example, according to the example above, in the event of a mains-side undervoltage, it can be provided that the mains-side LED 11, in particular red, then lights up, preferably without the load-side LED 12 lighting up. Similarly, according to the example above, in the event of a load-side differential current, it can be provided that the load-side LED 12, in particular red, then lights up, preferably without the mains-side LED 11 lighting up. To significantly improve visibility for the user, in the illustrated embodiment the mains-side LED 11 is arranged in the mains-side housing area 7 and the consumer-side LED 12 in the consumer-side housing area 8. To further optimize intuitive recognition by the user, in the illustrated embodiment the housing 2 has a length L measured along the longitudinal axis 5, and the mains-side housing area 7 and the consumer-side housing area 8 each have a length l measured along the longitudinal axis 5, which is at most 1 / 3, preferably at most 1 / 4, and particularly preferably at most 1 / 5, of the length L of the housing 2. Specifically, the length l in the illustrated embodiment is approximately 19.4% of the length L. The intuitive understanding by the user is further enhanced in the illustrated embodiment by placing an on / off button 13 behind the mains-side LED 11 when viewed in the longitudinal direction 6, and the consumer-side LED 12 behind the on / off button 13. That is, the on / off button 13 is positioned between the LEDs 11 and 12 and thus further contributes to the optical separation or differentiation of the LEDs 11 and 12 from each other. The on / off button 13, which is surrounded by the status indicator element 10 in a ring shape, can be used to activate the residual current device 1, so that, in a proper operating condition, i.e., when the residual current device 1 is connected to the low-voltage network and no fault condition is detected, a connected consumer is supplied with power via this device. In the illustrated embodiment, the status indicator elements 10, 10', 10'', as well as the mains-side LED 11 and the load-side LED 12, are arranged at least partially on a housing top 9 of the housing 2. The housing top 9 is not a flat surface, but rather three-dimensionally structured, although it points essentially or largely in one direction (out of the plane of the drawing in Fig. 1). Due to the arrangement of the status indicator elements 10, 10', 10'' and the LEDs 11, 12 on the housing top 9, the user can not only quickly and clearly identify whether a detected fault condition exists on the mains side or the load side (due to the LEDs 11, 12), but also simultaneously gain the ability to visually assess the type of fault, at least roughly (due to the status indicator elements 10, 10', 10''). REFERENCE MARK LIST 1 Residual current device 2 Housing 3 Mains connection 4 Load connection 5 Longitudinal axis 6 Longitudinal direction 7 Mains housing area 8 Load housing area 9 Housing top 10, 10', 10'' Status indicator 11 Mains LED 12 Load LED 13 On / Off button 14, 14' Cable gland 15 Control unit L Housing length l Mains / load housing area length QUOTES INCLUDED IN THE DESCRIPTION This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature EP 3057190 B1

[0005] EP 3016225 B1

[0006]

Claims

Residual current device (1) with a housing (2) extending along a longitudinal axis (5) in a longitudinal direction (6) from a network-side housing area (7) to a consumer-side housing area (8), wherein a network-side connection (3) for electrical connection to a low-voltage network is arranged in the network-side housing area (7) and a consumer-side connection (4) for electrical connection to one or more electrical consumers is arranged in the consumer-side housing area (8), wherein the residual current device (1) comprises a control unit (15) for detecting fault conditions, wherein at least one status indicator element (10, 10', 10'') controllable by the control unit (15) is arranged on the housing (2) for optical signaling of the presence of a fault condition, characterized in thatthat furthermore, at least one first display means (11) controllable by the control unit (15) and at least one second display means (12) controllable by the control unit (15) are arranged on the housing (2), wherein the control unit (15) is configured to generate an optical signal by means of the at least one first display means (11) when a fault condition due to a network-side fault is detected and to generate an optical signal by means of the at least one second display means (12) when a fault condition due to a consumer-side fault is detected. Residual current protection device (1) according to claim 1, characterized in that the at least one first display means (11) is arranged in the mains-side housing area (7) and the at least one second display means (12) is arranged in the consumer-side housing area (8). Residual current protection device (1) according to claim 2, characterized in that the housing (2) has a length (L) measured along the longitudinal axis (5) and that the mains-side housing area (7) and the consumer-side housing area (8) each have a length (l) measured along the longitudinal axis (5) which is at most 1 / 3, preferably at most 1 / 4, particularly preferably at most 1 / 5, of the length (L) of the housing (2). Residual current protection device (1) according to one of claims 1 to 3, characterized in that, viewed in the longitudinal direction (6), an on / off button (13) is arranged behind the at least one first display means (11) and behind the on / off button (13) the at least one second display means (12). Residual current protection device (1) according to one of claims 1 to 4, characterized in that exactly one first indicator means (11) and / or exactly one second indicator means (12) are provided. Residual current protection device (1) according to one of claims 1 to 5, characterized in that the at least one status indicator element (10, 10', 10'') is arranged at least section by section on a housing top (9) of the housing (2), that the at least one first indicator means (11) is arranged at least section by section on the housing top (9) and that the at least one second indicator means (12) is arranged at least section by section on the housing top (9). Residual current protection device (1) according to one of claims 1 to 6, characterized in that the at least one status indicator element (10, 10', 10'') comprises at least one light-emitting diode, that the at least one first indicator means (11) comprises at least one light-emitting diode and that the at least one second indicator means (12) comprises at least one light-emitting diode. Residual current protective device (1) according to one of claims 1 to 7, characterized in that the residual current protective device (1) is designed as a portable residual current protective device (1).

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