Many people including Home Inspectors use these standard testers already, but do not know they are incapable of testing a GFCI on a 2 wire circuit. The following is an excerpt from an email I got today from a Safety Consultant about a situation where an Electrician installled GFCI receptacles as a way to get 3 prong outlets (on 2 wire circuits) and avoid the use of adapters:
I recently revisited this employer and there are GFCI receptacles in the upstairs which was supposedly installed to correct the original condition. OF COURSE I tested several receptacles and they all reflected an open ground and would not trip with my receptacle tester, testing for ground fault. I wrote it up. Now I have a copy of the letter the contracting electrician sent to the city stating that NEC Article #406.3, D 3 (b & c) allows this type action. The problem I have is that the GFCI receptacles would not trip, so where is the protection? Is that OK or is there something else that this electrician could or should have done? The municipality sent the electricians letter to the building inspector and the building inspector stated that it was OK.....but I still have my doubts. Is this acceptable or is this a violation? I must have been born in Missouri and my Mother never told me!!
My question is if there is an easy way to tell this person (or others) how to test them and not just say "believe me, they'll work" ? It would have to be something simple with items readily available, or just a different/better tester.