GFCI and an Open Ground
Given: A 120 VAC GFCI supplying power to a 30 AMP RV. The RV has one problem, the 3rd Prong Ground wire at the 30 AMP plug is not making connection. (The RV chassis is floating because there are no ot...
Forum Discussion
Dutch_12078 wrote:
In reading through this thread, I think there's a lot of confusion between the neutral/ground bond at the primary distribution panel, and a safety ground that may have multiple grounding points. The safety ground is not used by the GFCI for detection purposes.
The GFCI doesn’t use the ground directly, but without some kind of ground connection to the service panel there can be no ground fault circuit to interrupt. Hence the name. This ground can be the 3rd pin, a metal water pipe or the earth itself.
Normally the circuit between the load and supply uses just the hot and neutral wires. Because neutral is bonded to ground and the earth, any ground or earth path (including a person) can inadvertently become a return conductor in addition to or lieu of the neutral. That is what a ground fault is and what the GCFI is trying to protect against.
So ground may not be “used” but is very relevant. A 2-pin device plugged into a GCFI receptacle hanging in mid air could never trip a GCFI. This is what started this discussion. An ungrounded RV that is insulated can’t either, so long as nothing or nobody “grounds” it. Practically speaking someone could walk up and touch it so not having a ground connection is dangerous.
