The NEC mandates GFCI protection in many areas of the home: bathrooms, garages, outdoor receptacles, crawl spaces, basements, kitchens and anything within six feet of a sink or water source. While that may seem like a lot, the entirety of a home is not covered.

What size electrical service requires ground-fault protection?

NEC® Article 230.95 states that ground-fault protection of equipment shall be provided for solidly grounded wye electrical services of more than 150 volts to ground, but not exceeding 600 volts phase-to-phase for each service disconnecting means rated 1000 amperes or more.

Where ground-fault protection is required for A service What is the maximum time delay setting for ground-fault current in A system that is not coordinated?

The setting of the GFPE must not be greater than 1,200A and the maximum time delay before operation shall not exceed one second (60 cycles) for ground-fault currents of 3,000A or greater.