Ground fault responsive protective system for electric power distribution apparatus

Claim 1

A GROUND FAULT PROTECTIVE SYSTEM FOR A.-C. ELECTRIC POWER APPARATUS COMPRISING: (A) A FIRST MULTIPOLE CIRCUIT INTERRUPTER ADAPTED TO BE CONNECTED TO A POLYPHASE SOURCE OF ELECTRIC POWER, SAID SOURCE HAVING A NEUTRAL TERMINAL; (B) A PLURALITY OF ADDITIONAL MULTIPOLE CIRCUIT INTERRUPTERS CONNECTED TO SAID FIRST CIRCUIT INTERRUPTER; (C) A GROUNDED METAL STRUCTURE FOR HOUSING ALL OF SAID CIRCUIT INTERRUPTERS AND THEIR INTERCONNECTIONS; (D) A PLURALITY OF MULTIWIRE FEEDER CIRCUITS EMANATING FROM SAID STRUCTURE AND CONNECTED THEREIN TO SAID ADDITIONAL CIRCUIT INTERRUPTERS, RESPECTIVELY; (E) GROUNDED METAL CONDUIT MEANS RESPECTIVELY EMBRACING SAID FEEDER CIRCUITS OUTSIDE SAID STRUCTURE; (F) FIRST CONDUCTING MEANS ADAPTED TO BE CONNECTED BETWEEN SAID CONDUIT MEANS AND THE NEUTRAL TERMINAL OF SAID SOURCE, SAID FIRST CONDUCTING MEANS BEING ELECTRICALLY INSULATED FROM SAID STRUCTURE; (G) SECOND CONDUCTING MEANS CONNECTED BETWEEN SAID STRUCTURE AND A PREDETERMINED PART OF SAID FIRST CONDUCTING MEANS;