Bill:
If there is not a grounded surface nearby in an older home and no equipment ground I think you would be hard pressed to be able to test a GFCI with out some kind of ground point.
Where I live it is standard practice to use the GFCI as stated in order to replace the old two wire receptacles with a 3-wire and no equipment ground.(labels applied accordingly) In that situation I dont see how you could test one. Now in the Bathroom that would be an entirely different story providing PVC hasnt replaced the original Galvanized pipe or copper.
Of course without a grounded reference point there is no danger of a shock in the first place and if there is none in the room why are they needed ?(Rhetorical Question)
Because the code wants to be all encompassing, and there is always the chance that the home could have hot-water or steam heat instead of forced-air, but if a forced air duct is in one of those rooms it could be used as a reference point. The FPN in 250.104 says to " Bonding all piping and metal air ducts wihtin the premises will provide additional saftey", if thats the case there should be a ' Ground Reference point' in each room. Presumeably.
Exccept for a Wiggy and some reference point I dont know of a tester that can test it without an egc.
Mark
