I have looked on here to see if anyone has posted this, but no luck. A friend of mine had his co-worker demonstrate something to him while on a business trip. Using a hairdryer with and integrated GFCI cord and plugging it into a GFCI receptacle, he filled up the sink with water and dropped the hairdryer into the sink. Neither of the GFCI's tripped. He said he was told two GFCIs cancel eachother out. I have not been able to find a discussion that verifys this, but using my own GFCI plug at home with another GFCI protected 4-gang plug I use on jobs, I could not get either GFCI to trip. Is this correct? Two GFCI's will cancel eachother?? Seems kind of dumb that all hairdryers have a built in GFCI cord, which negates the receptacle you plug into!! Thanks for your input!
