Question

The underwriters laboratories (ul) requirement for ? ground-fault circuit interrupters (gfcis) is that tripping shall occur when the continuous 60-hertz differential current exceeds six milliamperes, but it shall not trip at less than four milliamperes.

Answer 1

The answer is Class A.  The GFCI (Ground Fault Circuit Interrupter) will “sense” the difference in the amount of electricity flowing into the circuit to that flowing out, even in amounts of current as small as 4 or 5 milliamps. The GFCI reacts quickly (less than one-tenth of a second) to trip or shut off the circuit.