Economical Ground-Fault Protection Available with a Standard Low-Voltage Static Tripping System

Arcing ground-fault theories and general history are reviewed and some of the available methods of ground-fault protection on low-voltage systems discussed. The cost of compansons of various methods in common use today are made. An economical ground-fault protective device integral with the solid-state trip device on 600-volt drawout air circuit breakers is presented in detail and the typical coordination and protection possible is illustrated by curves. Thus the ground-fault problem can be overcome and in some cases at only a nominal increase in cost.