METHOD AND APPARATUS FOR PROTECTING ELECTRICAL SYSTEMS

摘要

PCT No. PCT/GB89/01508 Sec. 371 Date Jul. 30, 1991 Sec. 102(e) Date Jul. 30, 1991 PCT Filed Dec. 18, 1989 PCT Pub. No. WO90/07214 PCT Pub. Date Jun. 28, 1990.Apparatus for providing an electrical system with protection against electrical shock in the event of a ground fault. The electrical system supplies power from a central mains inlet to at least one local electrical device. The central mains inlet includes a central ground fault detector and interrupter actuatable upon detection of a first predetermined level of current imbalance to interrupt the central mains inlet. A local ground fault detector is associated with the at least one local electrical device and is actuatable upon detecting a current imbalance of a second predetermined level which is lower than the first predetermined level. Controls are effective upon actuation of the local ground fault interrupter to actuate the central ground fault detector to cause it to interrupt the central mains inlet.