Patrick, In response to your question:
>I didn't think GFI's used the ground lead. If >there weren't any electrocutions from ground >faults, it would not be related to the presence >of a GFI. >Having said that, I think a three-leaded version >of a GFI could protect against line-neutral >current imbalance, as well as high leakage >current. Does anyone sell them? According to the 1996 US NEC, 210-7 (a) all 15- and 20-ampere branch circuit receptacles must be of the grounding type (this includes all GFCI receptacles as required for kitchens, bathrooms, garages, etc.). A grounding type receptacle is one that has connections for a hot, neutral, and ground. Therefore, ALL standard GFCI receptacle's are what you call "three-leaded versions". Albeit, the GFCI circuitry is only connected to the hot and neutral as described in previous messages on this topic. For replacement of old two blade (non-grounded) receptacles in installations where there is no ground, 210-7 (d) of the NEC allows replacement with 3-blade GFCI receptacles that are marked "No Equipment Ground". That means that cord connected equipment designed with a chassis ground for safety (IEC class 1) will actually have the chaises floated when plugged into one of these receptacles. This is not an oversight on the part of the NEC writers but rather a vote of confidence in the additional safety provided by GFCI's compared to older non-grounded receptacles. Regards, Mark Christopherson, P.E. Irvine, California email [email protected] Phone 714 251-2860 Fax 714 251-2868
