Can you use a G.F.I. in an ungrounded outlet?...
The N.E.C. allows a G.F.C.I. to be used in an outlet with a two wire ungrounded cable, but this might not be that great an idea for several reasons.
First: The ground lug on a G.F.C.I. receptacle might give the false impression that the outlet has a grounding wire.
Second: The surge surpressors used for computers and other electronic equipment require a properly installed grounding wire to work correctly.
There are several other ways to ground outlets. Here is a couple of them. First...Find out if the metal box that holds the receptacles has a proper ground, if it does you can either run a pigtail from the threaded screw in the box to the ground on your receptacle, or install a self grounded type receptacle. Second...And possibly the best and safest way is to run grounded cable back to your panel for each branch circuit. Whichever way you decide to go, these outlets should be grounded for your own safety.
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