GFI Tripping

[mikedbom]

My two outdoor outlets have a common GFI located in our upstairs bathroom. It kept popping today and I was able to narrow it down to my gutter lights which are 4 strands of C9 LED's. I have one LE on the GFI circuit and with those C9's plugged into the LE, it would trip. So I moved the lights to my other LE that isn't on a GFI circuit but rather a surge protector and had no issues. I checked the cord and lights for grounds but there were none. My question is what would cause the GFI to trip if there wasn't a ground. Would too much current do it?  And is 4 LED strings enough current to trip?

Thanks.

[johno123]

I'm no electrician - but I have noticed that if I had a GFI circuit that was close to the amp limit for the breaker, then it seemed to be more likely to trip - regardless if it was raining or what type of equipment that I have on that circuit. 

My advice is to invest in a kill-a-watt and carefully measure everything on each circuit from your panel in your house.  Add em up, and make that sure that you are about 70% of the total capacity of that circuit breaker (Please folks, let me know if there is a different capacity that you use or if there is some electrical code reference that we should use instead)

Then, if you are still getting blown GFI's with your equipment track down if something is shorting or freyed.  GFI pops are annoying but should be taken seriously.  However - after I re-wrired my LE's to balance the load across more outlets then all my GFI pops have gone away. 

-John

[mikedbom]

I'm puzzled though cuz all channels were off and no problems. I tested that one channel with xlights and pop. I moved the plug to another channel and same thing. So it was just those 4 strings giving me hell. I tested all the other channels without those LEDs plugged in and all worked fine.

[Night Owl]

You say that you check the cord and lights for grounds.  How did you to that?  A GFCI measures the current flowing from the hot line to the neutral line.  If there is an imbalance, it will trip.  I think somewhere between 5-6 milliamps.  For example, say the insulation on one of the wires of the lights you have hung on your gutters is cut and it is touching your gutter.  Assume your gutter is metal and the downspout touches the earth.  When you plug in the lights, even a small amount of current traveling through that downspout will cause the CFCI to trip.  But if you use a multimeter and measure your ground line and your gutter, chances are you will see an open circuit.

So you took the the lights down and moved it to a different LE?  Or did you leave them up and just moved the plug to a different LE? 

[wwwgator]

Following Night Owls recomendations, try changing extension cords feeding the gutter lights.
 Try to isolate it down to the bare minimum. If you can take the lights down, do so. If not, make sure the e-cord is good- no cracks or look for any opening that moisture can get in. try another cord if possible.

GFCI do compare voltage out to voltage returned....3 cycles of unequal power is SUPPOSED to trip the device. One thing I have come across  is that when you have the GFCI in a bathroom that also feeds the outside outlets ( a mid 70-80's building metheod) the high current demand ( hair dryers/ curling irons) plus the humidity of the bathroom does have a tendancy to deteriorate the GFCI outlet and it's effectivness.
Current NFPA Code now requires dedicated GFCI for the bathroom to feed onlythat bathroom, no more looping it out to outdoors or kitchen ( also required)

[mikedbom]

@Night Owl - I tested for grounds using a meter...phase to phase, phase to ground.  The cord was good, no nicks or damage.  The lights on on the gutter are in plastic clips and are new this year.  I doubt any of the wires could have been damaged during installation.  Unless there is an outlet sitting in some standing water, that is something I have not checked on.

I left the lights up and just rerouted the extension cord to my other LE that is on a different circuit (not GFI). 

Definitely something going on with that set of lights so i'll have to do more checking. 

@gator - Could I replace the outlets outside with GFI and keep the one in the bathroom as well?  Its a pain to go upstairs and reset every time especially when troubleshooting.  Thanks for the info...i'm guessing the voltage imbalance may be related to water and not necessarily damage.  I will check it out when the rain lets up. 

[wwwgator]

Yes. but you have to do the following:
- turn off power to that bathroom
- VERIFY power is off to the bathroom
-remove the wires that land on the "load" side of the GFCI- these are the wires that go out to your outside outlets
- wirenut those to the supply wires that also feed the "line" side.
- install weather resistant GFCI at the outside location with an in use cover.

It's very important to test monthly per manufacture's instructions. Not only for your safety and peace of mind, but if not done, also it violates the warranty....not that we ALL havent violated those before......