An overvoltage protection circuit includes an input terminal, an output terminal, a clamp transistor, and a selector circuit. The clamp transistor is configured to control current flow between the input terminal and the output terminal. The clamp transistor includes a first terminal coupled to the input terminal, a second terminal coupled to the output terminal. The selector circuit is configured to control a resistance of the clamp transistor based on a voltage at the input terminal. The selector circuit includes a first terminal coupled to the first terminal of the clamp transistor, a second terminal coupled to the second terminal of the clamp transistor, and a third terminal coupled to a third terminal of the clamp transistor.

Electric vehicle supply equipment has a test circuit configured to be switchable from a first test mode to at least a second test mode. In the first test mode, the test circuit is configured to measure a first voltage difference between a live terminal and a neutral terminal, a second voltage difference between the live terminal and a reference ground terminal and a third voltage difference between a circuit protective conductor terminal and the reference ground terminal and to disconnect a charging supply if at least one of the first, second and third voltage differences exceeds a respective voltage limit. In the second test mode, the test circuit is configured to measure the first voltage difference and to disconnect the charging supply if the first voltage difference exceeds a respective voltage limit and not to disconnect the charging supply in response to any test of the second or third voltage differences. The voltage limit for the first voltage difference is configured to be greater in the first test mode than in the second test mode.

Method for detecting a protective conductor failure inside a cable including a plurality of conductors, in which at least one conductor has a shield and this shield is respectively connected to a potential at a first end and at a second end of the cable, wherein, in order to drive its potential to a predefined potential value, the shield is actively electrically supplied at at least one end of the cable. In this case, the cable may be a charging cable which is connected, by the first end, to a charging pole and is connected, by the second end, to a battery configured to be installed in an electric vehicle, and the shield is actively supplied at the first end of the cable which is connected to the charging pole.

Method for detecting a protective conductor failure inside a cable including a plurality of conductors, in which at least one conductor has a shield and this shield is respectively connected to a potential at a first end and at a second end of the cable, wherein, in order to drive its potential to a predefined potential value, the shield is actively electrically supplied at at least one end of the cable. In this case, the cable may be a charging cable which is connected, by the first end, to a charging pole and is connected, by the second end, to a battery configured to be installed in an electric vehicle, and the shield is actively supplied at the first end of the cable which is connected to the charging pole.

A circuit is protected from sudden potential fluctuations that occur in a power ground. An in-vehicle protection apparatus includes a first Zener diode portion, a second Zener diode portion, a diode portion, and an intermediate conductive path. A voltage based on a power source is applied to the anode side of the diode portion. The intermediate conductive path is provided with a branch portion at one end, and forms a path between the cathode of the diode portion and the branch portion. The cathode of the first Zener diode portion is electrically connected to the branch portion and the anode of the first Zener diode portion is electrically connected to a power ground line. The cathode of the second Zener diode portion is electrically connected to the branch portion and the anode of the second Zener diode portion is electrically connected to a signal ground line.

An electrical installation includes: a switch cabinet; a protective switch arranged in the switch cabinet; and a cladding having electrical conductors and a voltage-measuring device/current-measuring device for measuring a current flowing through the electrical conductors, the voltage-measuring device/current-measuring device being operatively connected to the protective switch and being capable of triggering or switching off the protective switch when a measured value exceeding a threshold value is detected.

A leakage voltage detection system can be easily mounted on a ground structure such as an existing street light or a traffic light and can detect a leakage voltage of an electric structure in real time. The leakage voltage detection system includes a sensor node mounted on a ground structure, and an equipment management server that determines a risk of a leakage voltage in the ground structure based on detection voltage information from the sensor node. The sensor node includes an electric field probe that measures a potential difference caused by an electric field detected by electrodes, and a sensor box that detects the potential difference between the electrodes of the electric field probe and transmits the potential difference to the equipment management server as a detection voltage. The equipment management server determines the risk of the leakage voltage where the sensor node is mounted based on the received detection voltage from the sensor node, and outputs information on determination of the risk of the leakage voltage.

A method and system is provided which monitors and regulates induced ground-line power on a structure or organism. Further a method and system is disclosed which monitors and regulates induced ground-line power by regulating and harnessing small current flows generated by induced EMF exposure on the structure or organism as they flow through the attached system to an Earth ground connection point.

A ground overcurrent control system includes ground circuit with a first section and a second section. The first section is electrically connected to a ground member of an electrical connector and the second section is electrically connected to a ground reference. A switch element is positioned between the first section of the ground circuit and the second section of the ground circuit. A controller is configured to determine the current within the ground circuit while current is passing through the switch element and, upon the current exceeding a current threshold, the switch element is modified to an open condition. Upon determining that the voltage between the first section of the ground circuit and the ground reference is less than a voltage threshold, a command is generated to modify the switch element back to a closed condition.

A ground overcurrent control system includes ground circuit with a first section and a second section. The first section is electrically connected to a ground member of an electrical connector and the second section is electrically connected to a ground reference. A switch element is positioned between the first section of the ground circuit and the second section of the ground circuit. A controller is configured to determine the current within the ground circuit while current is passing through the switch element and, upon the current exceeding a current threshold, the switch element is modified to an open condition. Upon determining that the voltage between the first section of the ground circuit and the ground reference is less than a voltage threshold, a command is generated to modify the switch element back to a closed condition.