Earth terminal solution for an electrical apparatus

Abstract

An electrical apparatus (1) configured for being connected to an electrical supply system having a terminal configuration according to an earthing system of either a non-PME type or a PME type for rec

Description

FIELD OF THE INVENTION The present invention relates to an earth terminal solution for an electrical apparatus, a method of connecting an earthing of an electrical supply system to an earth terminal of an electrical apparatus and a method of controlling that an apparatus has been correctly coupled to an earthing of an electrical supply system. BACKGROUND OF THE INVENTION In the UK, a majority of electricity consumers are connected to an electrical supply system with a so-called TN-C-S PME earthing system. For sake of simplicity, a TN-C-S PME system may henceforth in this document be referred to as a “PME system” or “an electrical supply system having a terminal configuration according to an earthing system of a PME type”. In a PME system, the electrical supply system has a live wire and a combined PEN (Protective Earth and Neutral) conductor. The PME system involves a significant risk of a hazardous error with the PEN-conductor, an error that may lead to e.g. an earthed part of an appliance connected to the network becoming live with voltage as high as the supply voltage, such as on a surface unprotected from human interaction. One way to mitigate the risk of a hazardous PEN-error is to install an earth rod, an extra earthing, external to the electricity grid, to which appliances may be connected. Another possible solution is to install an isolation transformer. None of the two solutions are ideal, for various reasons. A third option is to have a device included in an electrical apparatus, where the device is configured to ensure breakage from a power supply in the event of an earthing error. An example of such a device is disclosed in GB2589812 (A). The present invention solves the problem of providing a breakage from the electrical sup ply system in the event of an earthing error in an alternative way compared to the solution presented in GB2589812 (A). An issue with the solution described in GB2589812 (A) is that it is made for connection with a PME system only. For other electricity supply earthing systems there are typically a requirement that appliances connected to the grid offers an earth terminal for a direct earth connection. Such earthing systems includes e.g. a TN-S system, a TN-C-S system (without PME) and an IT system, and may henceforth for the sake of simplicity be referred to as a “non-PME system”. An electrical supply system having a “non-PME system” may also be referred to as “an electrical supply system having a terminal configuration according to an earthing system of a non-PME type”. An apparatus with the solution disclosed in GB2589812 (A) does not offer an earth terminal for direct earth connection, and thus should not be connected to a non-PME system. SUMMARY OF THE INVENTION The invention is defined by the independent claims. The dependent claims define advantageous embodiments. In a first aspect, the invention relates to an electrical apparatus configured for being connected to an electrical supply system having a terminal configuration according to an earthing system of either a non-PME type or a PME type for receiving electricity from the electrical supply system, the electrical supply system comprising an earthing, the apparatus comprising: an internal earth conductor for being connected to an internal circuitry of the electrical apparatus; a detecting device for detecting a ground fault in the electrical supply system; a breaker device being configured for breaking a circuit in the apparatus when the ground fault is detected by the detecting device, the breaker device comprising at least one circuit breaker; a first earth terminal for providing a direct earth connection between the internal earth conductor and the earthing of the electrical supply system in case the earthing system is of the non-PME type; a second earth terminal for providing a connection between the earthing of the electrical supply system and the internal earth conductor via the at least one circuit breaker in case the earthing system is of the PME type. The detecting device may be a device for detecting a fault in the electrical supply system. In embodiments of the invention the apparatus may also be configured for detecting other errors in the supply of electricity than a ground fault. The breaker device may be configured for breaking the circuit in the event of detection of a defined category of errors in the electrical supply system, which may be errors of a certain nature or a certain magnitude. A ground fault may also be referred to herein as “an error in the earthing” or similar. The apparatus according to the invention creatively and elegantly solves the problem of making the apparatus compatible with both a PME system and a non-PME system, without requiring an external earthing or an isolation transformer or other external solutions. By making the apparatus compatible with different earthing systems that exist in the same country, region and / or market, the solution offers a great advantage compared to prior art. Logistics are made easier for both producers, retailers and consumers. Furthermore, the risk of a retailer selling or a consumer buying a product that is not compatible to the electricity grid to which the product is to be connected is reduced or eliminated. All that is required for correct installation of the apparatus is for the installer to know the type of net to which the apparatus is to be installed, and couple an earth wire from the electrical supply system to the correct earth terminal for the earthing system of the electrical supply system. In an embodiment of the invention, the apparatus may comprise a charging station (charger) for an electric vehicle. However, it must be noted that the solution may be applied to many other types of electrical apparatuses. The apparatus may be a type of apparatus or appliance for domestic use, such as an electrical grill, a lamp, a power tool, a cement mixer, outdoor kitchen appliances, etc. The apparatus may be e.g. a household apparatus or an apparatus for industrial use. The solution of having two earth terminals was counter intuitive, as the solution may come with a risk of an erroneous earthing connection between the apparatus and an electrical supply system which may be hazardous. If, for example, a consumer has a PME system, and mistakenly connects earth to the first earth terminal, an earthed part of the apparatus or a device connected to the apparatus may become live and potentially hazardous. In the same example, if the apparatus is a charger for an electrical vehicle (EV), such a mistake combined with a critical earth failure may lead to the chassis of an electrical vehicle connected to the charger becoming live with potential for causing considerable harm to a person touching the chassis. It could also be problematic if a consumer that has a non-PME system had connected earth to the second earth terminal. However, this issue has been addressed through further creative effort: The detecting device for detecting a ground fault may in an embodiment e.g. by measuring a difference in a voltage between a neutral conductor in the apparatus and a L1 conductor in the apparatus, wherein the difference is a difference from a normal or expected voltage. The detecting device may be configured to register as an error in the earthing a difference that is e.g. ±5% relative to the normal or expected voltage, ±10% relative to the normal or expected voltage, ±15% relative to the normal or expected voltage, or any defined difference under 5% or over 15% of the normal or expected voltage. In alternative embodiments, the detecting device may be configured for measuring e.g. a current in one or more conductors of the apparatus. However, measuring changes in voltage may be more advantageous relative to measuring current, as voltage measurements may allow for earlier detection of potentially hazardous fault. The detecting device for detecting a ground fault may in an embodiment be configured to detect another error in the supply of electricity in the electrical supply system, e.g. by measuring a difference in a voltage between two conductors or over two components in a circuitry in the apparatus, or by measuring a current in a conductor. The apparatus may further comprise an earth connection detector. The earth connection detector may be a device for detecting which earth terminal of the apparatus that is connected to an earthing in the electrical supply system. The earth connection detector may alternatively or additionally be configured to determine if the earthing of the electrical supply system connected to the apparatus is of a PME system. The earth connection detector may alternatively or additionally be configured to determine if an installer has neglected to connect the earthing of the electrical supply system to one of the earth terminals of the apparatus. The earth connection detector may further or alternatively be configured to determine if a non-earthing conductor, such as a L1, L2, or L3 conductor is coupled to an earth terminal. In general, the earth connection detector may advantageously mitigate risk of a human error in connection of earthing to the apparatus by enabling detection of an erroneous connection. The apparatus may comprise a communication device for communicating data to a receiver. The apparatus may be configured to upload data, to download data or to upload and download data. The data may be data e.g. for use in improving a performance of the apparatus, for use to report a performance of the apparatus, for use to report a detected error, and / or for use to detect or identify an error. The earth connection detector may comprise or be connected to the communication device for use of the communication device. However, the communication device may also be used for other purposes than purposes of the earth connection detector. The communication device may e.g. be used to upload information obtained by the earth connection detector about an earth connection to a computer device. The computer device may have stored information about what type of earthing system the apparatus is connected to. The computer device may comprise software for comparing data from the earth identifier device with said stored information about the type of earthing system, and determining based on the comparison if the earthing is correctly connected to the apparatus. The communication device may then be configured to communicate to the apparatus whether or not the earthing is correctly installed. The apparatus may comprise the computer device or one or more parts of the computer device. The apparatus may comprise the software or one or more lines of code of the software. The apparatus may comprise information stored in the software / in the computer device, such as e.g. information about the type of earthing system. The software may comprise code to compare information stored about the apparatus to information stored about other apparatuses installed in a vicinity and / or connected to the same electrical supply system as the apparatus. The other apparatuses may be of the same type as the apparatus, may be other or similar embodiments of the invention as the apparatus, or they may be other types of apparatus connected to the same computer device for storing information about the apparatuses. The software may be configured e.g. to compare registered data to find a discrepancy between registered data of the apparatus compared to registered data of other apparatuses that are or that are likely to be connected to the same electrical supply system. The software may further be configured to send a warning if a discrepancy is found, such as if it appears that the earthing system registered for the apparatus seems erroneous in comparison to that of other apparatuses connected to the same or likely to be expected to the same electrical supply system. The apparatus may comprise an app through which an owner of the apparatus may receive information, such as warnings issued by the apparatus another device, such as the mentioned computer device, connected to the apparatus. The apparatus may be configured to provide information to a user via the app. The apparatus may be configured to receive input from a user via the app. The apparatus may be configured to communicate with other apparatuses of the same kind connected locally to a mutual network, such as a wi-fi network or via Bluetooth. The apparatus may be configured to compare registered or detected information between one or more apparatuses of the same kind connected locally to the mutual network, to identify one or more errors in installation or in a supply of electricity. What is referred to as “registered information” may be information that is manually registered by e.g. an installer of an apparatus, an owner of a network, and / or an owner of an apparatus. The apparatus may comprise a signalling device to signal to a user, an owner or any other person e.g. a fault or if the earthing is correctly installed. The signalling device may comprise e.g. one or more light emitting devices and / or one or more sound emitting devices. The light and / or sound emitting device or devices may be parts of the electronics unit or parts of a cover for the electronics unit. By having some or all of the features mentioned above, the apparatus may mitigate the risk of erroneous connection, and possibly also provide information to people who can be said to be stakeholders in the safety of the apparatus, such as e.g. the user and the installer of the apparatus. The information may be provided e.g. by the emitting of a sound or a light signal from the apparatus, or e.g. by displaying a message or a sign on a display on the apparatus. The apparatus may comprise a display for displaying a message or a sign. The breaker device may be a device creating a mechanical break in connection in a circuit in the apparatus. The breaker device may comprise one or more circuit breakers. The one or more circuit breakers may be e.g. one or more relays and / or one or more contactors and / or one or more other parts for creating a break in a circuit. The breaker device may be configured for creating a break in the circuit for a limited period of time and to re-establish the circuit after said period of time. The breaker device may comprise one or more switches. The breaker device may comprise a plurality of circuit breakers. The breaker device may comprise one or more circuit breakers in one or more conductors in the apparatus. The breaker device may be configured to break a plurality of circuits / conductors simultaneously, or through a series of breaks one after the other. In an embodiment, each one of a conductor leading from a neutral terminal of the apparatus, a conductor leading from a L1 terminal of the apparatus and a PME conductor of the apparatus may comprise a circuit breaker. The breaker device may be configured such as for the circuit breaker in the neutral conductor and in the L1 conductor to break their respective circuits first in the event of a detected error by the detecting device, prior to the circuit breaker in the PME conductor. The circuit breaker in the PME conductor may be the circuit breaker arranged between the second earth terminal and the internal earth conductor. The apparatus may comprise a controller device. The controller device may comprise e.g. one or more microcontrollers (MCU), one or more central processing units (CPU), one or more complex programmable logic devices (CPLD), and / or one or more field programmable gate arrays (FPGA), and / or one or more of any other type of suitable processing devices. In embodiments of the invention, the one or more or plurality of circuit breakers may be controlled by the controller device. The controller device may be part of or connected to the detecting device, it may be part of or connected to the breaker device, and it may be configured to gather and interpret data from a circuitry to detect the ground fault in the electrical supply system. The controller device may be connected to circuitry of the apparatus to make readings from the circuitry. The controller device may comprise a voltage measurement device and / or a current measuring device. The controller device may be configured for determining, based on input and / or measurements, if there is, and / or if there is not, an error, such as a ground fault or another error in the supply of electricity from the electrical supply system. The controller device may be configured to send one or more signals to the breaker device based on the determinations and / or the data / inputs received, to operate the breaker device. The detecting device may be configured for detecting an earthing error by detecting a change in a voltage between two conductors, the change being a change from a voltage in a range defined as normal and acceptable to a voltage outside of said range. In an alternative embodiment, the detecting device may be configured for detecting e.g. an unexpected or unacceptable deviation from a normal currency in a conductor. The apparatus may comprise a base unit comprising the first earth terminal and the second earth terminal. The base unit may further comprise an L1 terminal and a neutral terminal for connection of an L1 wire and a neutral wire respectively from an electrical supply system to the base unit. The base unit may comprise further terminals. The base unit may be configured for connection of the apparatus to an electrical grid for supply of electricity to the apparatus. Furthermore, the apparatus may comprise a base unit cover, for covering the base unit after installation of the base unit and prior to installation of an electronics unit. The apparatus may further comprise an electronics unit for using supplied electricity for performing whatever task the apparatus is made to perform. The base unit and the electronics unit may be configured to fit together by plugging the electronics unit into the base unit. The electronics unit may be configured such that connecting the electronics unit to the base unit and therethrough to the electrical supply system is straightforward. In embodiments of the apparatus, the electronics unit may fit into the base unit in such a way that any user or owner of the apparatus may simply need to place the electronics into the back plate and click the base unit and the electronics unit together for the two parts to connect. The base unit and the electronics unit may be configured to be connected without requiring the person that connect the two to know anything about the earthing of the electrical supply system to which the backplate is connected and the electronics unit through the backplate is to be connected following the connecting of the two parts. The electronics unit may typically, but not necessarily, comprise e.g. the breaker device, the detecting device, and the earth connection detector, and the controller device. In alternative embodiments, another unit may comprise e.g. the breaker device and / or the detecting device, such as e.g. the base unit. The base unit may, in some embodiments, comprise some electronic components and circuitry. In some countries and / or jurisdictions, an electrician may be required to perform a fixed installation of an apparatus to an electrical supply system. The installation of the base unit to the electrical supply system may be considered to be such a fixed installation requiring an electrician in such countries and / or jurisdictions. The connection of the electronics unit to the base unit, however, may be considered to not be such a fixed installation and therefore to not require an electrician for the installation. Connecting the electronics unit to the base unit may be of a nature that is allowable to be performed by any person, or by any person over a given age, even in countries where fixed installations to electrical supply systems must be made by electricians. Having a base unit to be installed by an electrician and a separate electronics unit that may be connected to the base unit by any user regardless of qualifications may be highly advantageous. In the event of a faulty electronics unit, the electronics unit of the apparatus according to the invention can simply be changed without the assistance of an electrician. The same goes for e.g. an upgrade of the electronics unit. The clever combination of a base unit and an electronics unit also allows for the possibility of using an electrician for setting up a plurality of base units in a one-time operation that prepares for procurement of one or more electronics units at a later date and a subsequent installation that does not require assistance of an electrician. An example of such a scenario is as follows: An apartment building is constructed. Prior to sale of apartments, the owner of the building wants to facilitate for safe charging of EVs in a basement parking lot in the building. In this scenario, the apparatus according to the invention is a charger for an EV, the base unit is a backplate and the electronics unit is referred to as a “chargeberry”. The owner of the building installs backplates for each of the parking spots in the parking lot, making the parking lot ready for subsequent installation of chargeberries to complete installation of chargers. As an apartment is sold to a resident that owns an EV, said resident may wish to own a charger for the EV for his parking spot in the parking lot. The resident may then simply acquire a chargeberry and connect the chargeberry to the backplate, without needing assistance from an electrician. The resident does not need to know what kind of earthing the electrical supply system coupled to the backplate has, the chargeberry may be configured to work regardless of type of earthing. Note that the above is merely an example, and that the apparatus according to the invention may be another kind of electrical apparatus than a charger for an EV. The apparatus may be an apparatus for providing electricity to another device or apparatus, such as in the case of a charger. The apparatus may have one earth output terminal. Both the first and the second earth terminal may lead to the one earth output terminal through the mutual earth conductor. In a second aspect, the invention relates to a method of connecting an earthing of an electrical supply system to an earth terminal of an electrical apparatus in accordance with the first aspect of the invention, wherein the method comprises the steps of: acquiring knowledge regarding whether the electrical supply system the earthing system of the electrical supply system is a PME system or a non-PME system; based on the knowledge acquired in the preceding step, coupling the earthing of the electrical supply system to the correct one of the first and the second earth terminal. In a third aspect, the invention relates to a method of controlling that the apparatus according to the first aspect of the invention has been correctly coupled to an earthing of an electrical supply system, the method comprising the steps of: obtaining by use of the earth connection detector, as a first point of data, to which one of first earth terminal and the second earth terminal of the apparatus the earthing of the electrical supply system has been connected; registering, as a second point of data, what type of earthing system the electrical supply system connected to the apparatus has; comparing the first point of data with the second point of data for determining if the apparatus has been correctly coupled to the earthing of the electrical supply system. The registering of data may be e.g. a manual entry by a person such as a user, an installer, an owner or a retailer of the apparatus, based on information said person has obtained. The registered data may be registered in a computer device. The second point of data and the first point of data may be communicated to a computer device for comparison of the two points of data by the computer device. If the two points of data are found not to correspond, in the sense that the first points of data shows that the earthing is connected to the wrong terminal given the type of earthing the electrical supply system has, the computer device may be configured to communicate a warning signal to a user e.g. through an app or through the apparatus or otherwise. The earth connection detector may comprise an arrangement of electrical components, such as e.g. one or more resistors and / or one or more capacitors, and one or more measurement devices for measuring devices for measuring a voltage or a current. The arrangement of electrical components may be connected to conductors in the apparatus. BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 Shows an embodiment of an apparatus according to the first aspect of the invention; Fig. 2 Shows a base unit of the apparatus of Fig. 1; Fig. 3 Shows an electronics unit of the apparatus of Fig. 1; Fig. 4 Shows a simplified electric wiring diagram of the electronics unit of the apparatus of Fig. 1 that includes the main components of the detecting device and the breaker device; and Fig. 5 Shows an alternative embodiment of the simplified electric wiring diagram. DETAILED DESCRIPTION OF THE EMBODIMENTS The figures and the following text will provide insight into and a detailed description of one particular embodiment of the apparatus according to the first aspect of the invention. It is of great importance to note that the focus will be on providing information that enables recreation of the invention, that all details of the apparatus itself may not be disclosed, and that it must be understood that the invention is not exclusively useable in this particular apparatus nor that the layout or combination of features disclosed herein is the only possible one within the scope of the invention. In what follows is merely described an example of an embodiment, that should not be seen as exclusive of others. The embodiment of the invention that will be presented is what may be referred to as e.g. “a charger for an electric vehicle”, “a car charger” or “a charging robot for an EV”. Herein it will mainly be referred to as “the apparatus” 1. The apparatus 1 is shown in figure 1. The apparatus 1 itself does not have any earthed surface that is immediately touchable for a user in normal use of the apparatus 1. As such, the apparatus 1 itself will not become hazardous in case of an earthing errors when coupled to a PME earthing system, and will therefore not require an extra external earth safety device like an earthing rod or an isolation transformer. However, the apparatus 1 is configured to provide an electrical connection to an EV from an electrical supply system, including an earthing. The EV does have a surface that can become live and hazardous in the event of an earth error, so earth protection is therefore highly advantageous. The apparatus 1 offers such an advantageous earth protection. The apparatus 1 has three main parts that together make out the apparatus 1: A base unit, referred to as ”a backplate” 2, an electronics unit, referred to as a “chargeberry” 3, and a front cover 4. The backplate 2, shown in Figure 2, comprises four terminals 20 for connecting the apparatus 1 to an electrical supply system: a first earth terminal 21, a neutral terminal 22 and an L1 terminal 23, and a second earth terminal 24. The first earth terminal 21, which may be referred to as a “PE terminal” 21, is for connection to an earthing of a non-PME earthing system of an electrical supply system. The second earth terminal 24, which may be referred to as a “PME terminal” 24, is for connection to an earthing of a PME earthing system of an electrical supply system. The neutral terminal 22 and the L1 terminal 23 are for connecting to neutral and L1 of an electrical supply system respectively. The apparatus 1, in this particular embodiment, is primarily for connection to a single-phase electrical supply system, although it could also be used for e.g. a three-phase electrical supply system. The four terminals 20 of the backplate 2 are configured for, in addition to receiving and connecting to wires from an electrical supply system, receiving and connecting to connection pins 30 of the chargeberry 3. Additionally, the backplate 2 has a first part 48 of a means of connection 40 for releasably connecting the chargeberry 3 to the backplate 2. Figure 3 shows the backside of the chargeberry 3, an electronics unit that comprises electronic circuitry and components configured for controlling and passing on electricity from the electrical supply system to an EV connected to the apparatus 1. The backside of the chargeberry 3 has four pins 30 to fit into and connect with the four terminals 20 of the backplate 2. Naturally, each of the four pins 30 have a corresponding one of the four terminals 20 to fit into: There is a first earth pin 31 to fit into the PE terminal 21, a neutral pin 32 to fit into the neutral terminal 22, a L1 pin 33 to fit into the L1 terminal 23, and a PME pin 34 to fit into the PME terminal 24. The four pins 30 are configured for connecting to the four terminals 20 for connecting the circuitry in the chargeberry 3 to the electrical supply system. The chargeberry 3 further has a second part 49 of the means of connection 40 for releasably connecting the chargeberry 3 to the backplate 2. The means of connection 40 for releasably connecting the chargeberry 3 to the backplate 2 is configured for the second part 49 to fit into the first part 48, and for the two to click together by moving the chargeberry 3 relative to the backplate 2 in a correct direction. It must be noted that alternative embodiments of means of connection for releasably connecting the chargeberry 3 to the backplate 2 are possible. A circuitry 100 in the apparatus 1 is shown in Figure 4. It is important to note that it does not show the entire circuitry of a typical charger for an EV, but a simplified version to illustrate and explain the earth connection detector 18, the detecting device 19 and the breaker device 17. As have been previously mentioned, the earth connection detector 18 is a device for detecting which one earth terminal of the first earth terminal 21 and the second earth terminal 24, if any, is connected to an earthing of the electrical supply system. The detecting device 19 is included to detect an error in an earthing of the electrical supply system, and the breaker device 17 is included to break one or more circuits in the apparatus 1 in the event of a detected failure in the earthing of the electrical supply system. The circuitry 100 shown schematically shows the four aforementioned terminals 20 (may be referred to as “input terminals” 20) that are used to connect the apparatus 1 to the electrical supply system and output terminals 170 that are used to connect the apparatus to an EV, and conductors and electric components placed in between said terminals 20 and output terminals 170. The output terminals 170 includes an earth output terminal 171, a neutral output terminal 172, and a L1 output terminal 173. The circuitry 100 shown is a simplified version of the circuitry of the charger an embodiment of the earth connection detector 18, a device included in the apparatus 1 for detecting which one earth terminal of the first earth terminal 21 and the second earth terminal 24, if any, is connected to an earthing of the electrical supply system. The circuitry 100 includes a capacitor 101 coupled to a L1 conductor 130 and a PME conductor 140, a first resistor 102 coupled to a PE conductor 110 and a neutral conductor 120, a second resistor 103 coupled to the PE conductor 110 and the L1 conductor 130, a third resistor 104 coupled to the PE conductor 110 and the PME conductor 140, a first relay 121 in the neutral conductor, a second relay 131 in the L1 conductor, and a third relay 141 in the PME conductor 140. The PE conductor 110 may be referred to as the internal earth conductor 110. The PME terminal 24 is connected to the internal earth conductor 110 through the third relay 141. The internal earth conductor 110 has two branches, the two branches leading to and being connected to each other at the earth output terminal 171. One of the branches leading from the PE terminal 21 to the earth output terminal 171, the other from the third relay 141 to the earth output terminal 171. The circuitry further comprises an MCU (microcontroller) 190 connected to the PE conductor 110, the neutral conductor 120, the L1 conductor 130 and the PME conductor 140, each via an input line 199, for e.g. measuring a voltage between the conductors 110, 120, 130, 140. By measuring a voltage V1 between the PE conductor 110 and the neutral conductor 120, a voltage V2 between the neutral conductor 120 and the L1 conductor 130, and a voltage V3 between the neutral conductor 120 and the PME conductor 140, it is possible to determine to which one, if any, of the PE earth terminal 21 and the PME earth terminal 24 the earthing of the electrical supply system is connected. It is also possible to determine if no earthing has been connected to any of the two earth terminals 21, 24. The first, second and third relays 121, 131, 141, are parts of the breaker device 17 for breaking a connection between the electrical power supply and parts of the apparatus 1 in case of detection of an earthing error. The relays 121, 131, 141 are connected to the MCU 190 for control of the relays 121, 131, 141, each via an output line 198. If the earthing of an electrical supply system is coupled to the PE terminal 21, V1 will show a low voltage due to the earthing and the neutral of the electrical supply system being connected either in a transformer station or later in a network leading up to the connection to the of the electrical supply system to the apparatus 1. Due to the capacitor 101 and the third resistor 104 acting as voltage dividers in the circuitry 100, V3 will show a known voltage while the relay 141 is open, and a low voltage when the relay 141 is closed. If the earthing of an electrical supply system is coupled to the PME terminal of the apparatus 1, V3 will be a low voltage due to the earthing and the neutral of the electrical supply system being connected either in a transformer station or later in a network leading up to the connection to the of the electrical supply system to the apparatus 1. Due to R1 and R2 acting as voltage dividers, V1 will be a high voltage when the relay 141 is open and a low voltage when the relay 141 is closed. If no earthing is connected to any one of the PE terminal 21 or the PME terminal 24, V1 will be a high voltage when the relay 141 is open and a lower but not-close-to-zero voltage when the relay 141 is closed due to the third resistor 104 and the capacitor 101 then acting as voltage dividers. Due to the differences in the measured voltages depending on the status of the relay 141 in the different scenarios, it is possible to determine accurately a status of earthing connections to the apparatus 1. It is important to note that the circuitry 100 as shown and described is merely one of many possible examples of circuitry that may perform the earth connection detection and the breaking of the power supply from the electrical power supply to an earthed part of an apparatus 1 that may be touchable during normal use. It is also important to note that the circuitry 100 does not make out the entire electrical circuitry of a charger, it merely gives an example of a possible embodiment of the earth connection detector 18, the breaker device 17 and the detecting device 19. The MCU 190 comprises a voltmeter to measure the previously mentioned voltages V1, V2 and V3. Inputs are provided to the MCU 190 from the PE conductor 110, the neutral conductor 120, the L1 conductor 130 and PME conductor 140. The MCU 190 may also typically receive input from other sources, such as from temperature sensors (not shown), from one or more other MCUs (not shown), and from a communication device (not shown). Information received from the input is processed in the MCU 190, and e.g. used to control the relays 121, 131, 141, to communicate to a cloud system via a communication device (not shown) of the apparatus 1, and / or to operate e.g. a one or more LEDs to provide visual information to an operator or user of the apparatus 1. The detecting device 19 for detecting a ground fault in electrical supply system comprises the MCU 190 and is coupled to the neutral conductor 120 and the L1 conductor 130 to measure a voltage between the two. Typically, the detecting device 19 will be configured to react to detecting a measured voltage of ±10% relative to a defined normal voltage and then in the event of such a detection to send signals to the relays 121, 131, 141, to open to break the neutral conductor 120, the L1 conductor 130 and the PME conductor 140 to break supply of electricity to an EV coupled to the apparatus 1. The breakage will typically be temporary, and automatically ended when the detecting device 19 has measured normal values for a pre-defined suitably long period of time, such as e.g. 5 minutes, 10 minutes or more than 10 minutes. Figure 5 shows an alternative circuitry 109, wherein the alternative circuitry 109 has all the components and features of the circuitry 100 and an additional capacitor 105, the additional capacitor 105 being coupled to the neutral conductor 120 and the PME conductor 140. By including the additional capacitor 105, the previously mentioned detection of which one of the first earth terminal 21 and the second earth terminal 24 that is coupled to the earthing of the electrical supply system becomes possible even if an installer of the apparatus 1 has made the error of coupling L1 of the electrical supply system to the neutral terminal 22 and neutral of the electrical supply system to the L1 terminal of the apparatus 1.

Claims

1. An electrical apparatus (1) configured for being connected to an electrical supply system having a terminal configuration according to an earthing system of either a non-PME type or a PME type for receiving electricity from the electrical supply system, the electrical supply system comprising an earthing, the apparatus (1) comprising:an internal earth conductor (110) for being connected to internal circuitry (100) of the electrical apparatus (1);a detecting device (19) for detecting a ground fault in the electrical supply system;a breaker device (17) being configured for breaking a circuit in the apparatus (1) when the ground fault is detected by the detecting device (19), the breaker device (17) comprising at least one circuit breaker (121, 131, 141);a first earth terminal (21) for providing a direct earth connection between the internal earth conductor (11) and the earthing of the electrical supply system in case the earthing system is of the non-PME type;a second earth terminal (24) for providing a connection between the earthing of the electrical supply system and the internal earth conductor (110) via the at least one circuit breaker (121, 131, 141) in case the earthing system is of the PME type.

2. The electrical apparatus (1) according to claim 1, wherein the electrical apparatus (1) comprises a charging station for an electric vehicle.

3. The electrical apparatus (1) according to claim 1 or 2, wherein the electrical apparatus comprises an earth connection detector (18) for detecting a connection of the earthing of an electrical supply system to the apparatus (1).

4. The electrical apparatus according to claim 3, wherein the earth connection detector (18) is configured for detecting to which one of the first earth terminal (21) or the second earth terminal (24) the earthing of the electrical supply system is connected, and / or for detecting if the earthing of the electrical supply system is connected to any one of the first earth terminal (21) or the second earth terminal (24) at all.

5. The electrical apparatus (1) according to any one of the preceding claims, wherein the detecting device (19) is configured for detecting the ground fault by detectinga change in a voltage between two conductors, the change being a change from a voltage in a range defined as normal and acceptable to a voltage outside of said range.

6. A method of connecting an earthing of an electrical supply system to an earth terminal of an electrical apparatus (1) in accordance with any one of the preceding claims, wherein the method comprises the steps of:acquiring knowledge regarding whether the electrical supply system the earthing system of the electrical supply system is a PME system or a non-PME system;based on the knowledge acquired in the preceding step, coupling the earthing of the electrical supply system to the correct one of the first (21) and the second earth terminal (24).

7. A method of controlling that the apparatus (1) according to any one of claims 3 to 5, has been correctly coupled to an earthing of an electrical supply system, the method comprising the steps of:obtaining by use of the earth connection detector (18), as a first point of data, to which one of first earth terminal (21) and the second earth terminal (24) of the apparatus (1) the earthing of the electrical supply system has been connected;registering, as a second point of data, what type of earthing system the electrical supply system connected to the apparatus has;comparing the first point of data with the second point of data for determining if the apparatus (1) has been correctly coupled to the earthing of the electrical supply system.

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