The present invention provides a distribution board having a main breaker and a plurality of branch breakers, the distribution board being wired to branch power supplied to the main breaker into each branch breaker, the distribution board including: a plurality of noise detection sections configured to correspond to the respective branch breakers one-to-one and each configured to output a detection signal based on a noise component of not less than a predetermined frequency generated on a secondary side of each branch breaker; and processor configured to separately receive the detection signal output from each noise detection section and determine whether the detection signal is high frequency noise at a threshold or more.

An earthing module for a switchgear includes: a cylinder; a piston; a stored energy unit; and at least one photovoltaic cell. The cylinder connects to a part of a switchgear at earth potential. The piston moves within the cylinder from a standby position to a released position along an axis of the cylinder. When in the released position, the piston is in electrical connection with the cylinder. The stored energy unit is located within or associated with the earthing module such that activation of the stored energy unit moves the piston from the standby position to the released position. One or more of the at least one photovoltaic cell activates the stored energy unit based on radiation from an electrical arc of the switchgear impinging upon the one or more of the at least one photovoltaic cell.

An electric system has an electrical energy source connected to an electrical energy sink by at least one feeding line. Each feeding line (8) is in at least one position therealong between said source and said sink provided with an arrangement configured to interrupt arcing in the feeding line would such arcing reach this position. The arrangement has a temperature dependent member which upon an increase of the temperature thereof above a predetermined level activates an irreversible movement of movable means (24) which by this movement cuts off the arc (a) and/or removes hot ionized gases (28) and by that prevents the arcing to continue in the feeding line past the arrangement.

A system including ruggedized optic fiber cable assembly for use with an arc detection relay to protect electrical components from faults resulting in an arc flash. The cable assembly includes a pair of ruggedized ST connectors located at opposite ends of a ruggedized optical fiber cable. The cable includes an optical fiber core surrounded by a transparent gel layer and a transparent jacket surrounding the gel layer. Each ST connector includes a boot formed of a resilient material to provide shock absorption for the portion of the optical fiber cable extending through it. An accessory electronic cable is also provided, as are couplers, adapters for mounting the couplers onto walls, and sleeves with air pockets to enhance the ruggedness of the cable at points of stress, e.g., bends.

A system including ruggedized optic fiber cable assembly for use with an arc detection relay to protect electrical components from faults resulting in an arc flash. The cable assembly includes a pair of ruggedized ST connectors located at opposite ends of a ruggedized optical fiber cable. The cable includes an optical fiber core surrounded by a transparent gel layer and a transparent jacket surrounding the gel layer. Each ST connector includes a boot formed of a resilient material to provide shock absorption for the portion of the optical fiber cable extending through it. An accessory electronic cable is also provided, as are couplers, adapters for mounting the couplers onto walls, and sleeves with air pockets to enhance the ruggedness of the cable at points of stress, e.g., bends.

A sensing arrangement for detection of electrical discharges in an electrical apparatus is described. The sensing arrangement includes an acoustic sensor and a signal enhancing structure with a funnel region. The acoustic sensor is positioned outside the funnel region on an apex side of the funnel region. An electrical switchgear is described. The electrical switchgear includes a sensing arrangement for detection of electrical discharges in an electrical apparatus. The sensing arrangement includes an acoustic sensor and a signal enhancing structure with a funnel region.

A sensing arrangement for detection of electrical discharges in an electrical apparatus is described. The sensing arrangement includes an acoustic sensor and a signal enhancing structure with a funnel region. The acoustic sensor is positioned outside the funnel region on an apex side of the funnel region. An electrical switchgear is described. The electrical switchgear includes a sensing arrangement for detection of electrical discharges in an electrical apparatus. The sensing arrangement includes an acoustic sensor and a signal enhancing structure with a funnel region.

A system and method are provided to detect a fault on a circuit. A current sensor is provided for sensing current on at least one line conductor and/or a neutral conductor on a circuit, and a switch is operated between at least first and second positions to selectively control a signal pathway on the at least one line conductor or the neutral conductor in relations to the sensor. The sensor performs a first current measurement corresponding to current across one conductor from the at least one line conductor and the neutral conductor in the first position, and a second current measurement corresponding to a current balance or imbalance between the conductors in the second position. The current sensor outputs the first current measurement for detecting an arc fault in the first position, or the second current measurement for detecting a ground fault in the second position.

A system and method are provided to detect a fault on a circuit. A current sensor is provided for sensing current on at least one line conductor and/or a neutral conductor on a circuit, and a switch is operated between at least first and second positions to selectively control a signal pathway on the at least one line conductor or the neutral conductor in relations to the sensor. The sensor performs a first current measurement corresponding to current across one conductor from the at least one line conductor and the neutral conductor in the first position, and a second current measurement corresponding to a current balance or imbalance between the conductors in the second position. The current sensor outputs the first current measurement for detecting an arc fault in the first position, or the second current measurement for detecting a ground fault in the second position.

An earthing module for a switchgear includes: a cylinder; a piston; a stored energy unit; and at least one photovoltaic cell. The cylinder connects to a part of a switchgear at earth potential. The piston moves within the cylinder from a standby position to a released position along an axis of the cylinder. When in the released position, the piston is in electrical connection with the cylinder. The stored energy unit is located within or associated with the earthing module such that activation of the stored energy unit moves the piston from the standby position to the released position. One or more of the at least one photovoltaic cell activates the stored energy unit based on radiation from an electrical arc of the switchgear impinging upon the one or more of the at least one photovoltaic cell.