Ground fault detector for line-powered telephone network

A ground fault detection and power control system for a communications network having a conductive link for transporting telecommunication signals and power for one or more communication circuits coupled to said conductive link, comprising:

• an electrical excitation source coupled through an auxiliary conductive path coupled to said conductive link;
• and
• a ground fault sensor coupled in circuit with said auxiliary conductive path for monitoring said auxiliary path for a prescribed change in an electrical characteristic thereof representative of a person forming a ground fault with said conductive link by being coupled between said conductive link and a ground reference and, in response to said ground fault, being operative to protect said person from an electrical hazard by substantially reducing power applied to said conductive link.

A method of protecting service personnel from an electrical hazard resulting from a ground fault condition of a conductive link which is employed for transporting communication signals and supplying power sourced from a link power supply to one or more communication circuits comprising the steps of:

• (a) in response to said service personnel forming a ground fault between a ground reference and said conductive link, supplying loop current, from an excitation source separate from said link power supply, through a portion of said conductive link that includes said ground fault;
• and
• (b) in response to said loop current exceeding a prescribed threshold, protecting said service personnel from an electrical hazard by rapidly reducing the power supplied by said link power supply to said conductive link.