Arcing-Fault Relays for Low-Voltage Systems

On systems at 600 volts or less, even with modern, adequately rated protective devices, destructive and dangerous arcing faults may occur at low values of current. To prevent or reduce this damage, a new arcing-fault relay system has been developed to supplement phase overcurrent protective devices. Fast-acting arcing-fault relays sense arcing-fault current in conduit, busway, or switchboard enclosures, and cause main or feeder protective devices to interrupt the current quickly.