Is it ok to wire 2 or more GFCIs in series?
I have one receptacle string in my house where two GFCIs are wired, in series. Is that a problem?
In theory two in series should provide at least as much protection as having just on on the first receptacle in the string. But is there a chance that the two could somehow "synchronize/resonate" and end up not tripping or significantly delaying power shutoff?
Why do I have two GFCIs in a string and not just one on the first receptacle in the string? Because previous owner had already put a GFCI in the bathroom - which is somewhere midway in the string - and yesterday when I put GFCIs in the 1st receptacle of every string I saw no reason to bother reverting the bathroom GFCI to a regular receptacle.
BTW, I tested the protection at every receptacle by taking some current from the hot(black) wire and routing it through a 25W light bulb to the neutral(white) of another circuit to create an actual leakage. I noticed that for those receptacles that are after both GFCIs, both GFCIs tripped when I tested with the light bulb.