GFIC Oddity

Steve@Advance

Well-known Member
This weekend I installed 2 new Frigidaire 120v window unit air conditioners for a friend. This is new construction, they were mounted through the wall. I put the receptical near the unit. The AC's came with very long cords, with GFIC plugs. As planned, I opened the unit up, cut the excess cord length off and reconnected the cord. Plug it in... Instantly tripped the GFIC, both did the same thing. I know I shouldn't but I removed the GFIC and installed a regular plug, worked fine.

My question, did I get 2 defective GFIC's? Probably not.

What would shortening the cord have to do with tripping the GFIC? Done it before, no problems.

Only thing unusual I found was that both the power conductors inside the cord were foil wrapped with a tiny bare wire under the foil, like would be found in a shielded cable. Wondering if this was somehow connected inside the GFIC? Anyone seen this before?
 
Steve : I can't answer your question i googled a little and found those cords over a hundred bucks
I would do what you did regular plug, If i ever run into this it will be coil up wire and zip tie for me after seeing that price
Thanks
 
Any continuity between ground of the cord and neut of the cord? When you cut the cord maybe that inner foil crossed paths ? Odd problem for sure. Just to be clear the GFI device is on the units cord? Not required and also odd.
 
GFCIs will trip with only 5 milliamps difference between the two conductors. You must have caused a small crossover when you cut the cable. Maybe at the connections to the AC.
 
did it trip the gfcis before you shortened the cord? a neighbor built a garage and had an electrician wire it. he has a couple circuits with gfci's in them. if you used the first gfci, no problem , but anything plugged downstream would kick out the gfci's . turns out he daisy chained the neutral thru two gfci's on two different 110 v feeds. it would lose the neutral when the gfci tripped and the voltage went to about 170v while it was hunting for the neutral. it was a weird one.
 
Physically shortening a good cord wouldn't affect GFCI operation. However since it only takes like 5 milliamps to trip them as posted below I suspect a high resistance minor short was created somewhere.

John T
 
I'm pretty sure AFCI (arc fault circuit interrupters) are on all new a/c units. The conductors inside the cord are surrounded by a foil-like sheild which monitors leakage current and those sheilds are not grounded. I've never shortened one so not sure how it affects the arc monitor.
 
Ray, I think you may be right, maybe they are arc fault instead of ground fault. After cutting them off I read one of the tags on the cord, warned something about the foil covering not being grounded (not sure why that would be a concern of the consumer?) and if the cord cover is damaged to unplug it and discontinue use.

I did notice the raw ends of the foil covers were not visible on the end inside the case. There was a molded-on plastic ring covering the end where the wires came out. Thinking maybe the wires were connected together under the plastic ring and sent a completed circuit signal back to the AFCI, or possibly they were isolated from each other, something to do with monitoring the condition of the cordset insulation? Just my theory anyway!
 
Glenn, I didn't try before cutting them off. Should have, I would have been in a messy situation if there were a warranty issue.
 
Only thing odd here is WHY would anyone alter the cord on a new appliance?

Warranty would likely be voided and the person doing it would be liable for any shocks or fires that might later occur, not to mention in someone else's house!
 
Take the piece you cut off and use a VOM to verify where the shield wires are (or not) attached and duplicate on the cord you made.
 

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