ABSTRACT
Grounding isolates offending sections of the electrical system by selective relaying of ground faults. Sensitivity and time delays of the protective circuitry are adjusted. Protective circuitry is adjusted so that a fault in an area will cause a local breaker to sense a malfunction and quickly remove power from only that affected section. If relative tripping levels and speeds are not established correctly, then nearby breakers may not trip at the correct time. The relaying system must be arranged so that even at the lowest level of the power-distribution chain sufficient fault current can flow to enable the protective circuitry to sense the fault and take remedial action.
