Water tripping GFI circuit without penetration

[DaveC426913]

Is it possible that simply getting an outdoor electrical cord wet, it can somehow trip a GFI circuit?

I have a pool pump with its own waterproof cord (i.e. not an extension cord) and, as far as I can tell if the cord finds even a couple of feet of itself in a puddle of water, this will trip the GFI (which is about 20 yards away).

I don't mean during rain, I mean if the pool splashes and some water pools on the ground where the cord is, it will trip the breaker. If I lift the cord out of the water, I can reset the breaker and everything's fine.

I don't think there are any breaks in the cord. If there are, they must be too small to see (and I would think that simply lifting the cord would drain the water out - the water woulds stay stuck in any small crack.)

I'm wondering if the proximity of water to the wires (as opposed to air) thrugh the rubber casing can cause shiort through the rubber. (Kind of like electricity can jump an insulating gap of any size if the potential is great enough.)


So, how about it?

 

[berkeman]

Lifting the cord out of the water is eliminating the external path to ground, not draining the water out. My first guess is that the cord is bad. You can tell by unplugging it from the power outlet, and measuring the resistance to the puddle water with the cord first out of the puddle and then with it in. Measure each of the Hot and Neutral prongs to the puddle to see if you DVM comes down off of Overload with the contact.

If the cord is good, then that's a very strange effect. There shouldn't be enough differential displacement current from the conductors out to earth/puddle ground to trip the breaker, unless maybe the breaker is extra-sensitive and needs to be replaced. Do you have another GFCI outlet somewhere where you could make another ground puddle and see if the other outlet trips as well?

 

[DaveC426913]

Lifting the cord out of the water is eliminating the external path to ground, not draining the water out.

<strike>Sorry, that wasn't very clear. I was suggesting that, if it were a crack in the cord, and water was getting into the wires, then simply lifting it out of the puddle would not fix it, since enough wet would remain in the cord to cause the short. If water were actually getting into the wires, it would need to dry out in there before it would run again.</strike>

Oh I see what you're getting at! I was assuming the short was wire to wire. You're suggesting the short is wire to ground. Thus, wet or no, lifting it out of the puddle breaks the short to ground. Got it!

My first guess is that the cord is bad. You can tell by unplugging it from the power outlet, and measuring the resistance to the puddle water with the cord first out of the puddle and then with it in. Measure each of the Hot and Neutral prongs to the puddle to see if you DVM comes down off of Overload with the contact.

If the cord is good, then that's a very strange effect. There shouldn't be enough differential displacement current from the conductors out to earth/puddle ground to trip the breaker, unless maybe the breaker is extra-sensitive and needs to be replaced. Do you have another GFCI outlet somewhere where you could make another ground puddle and see if the other outlet trips as well?

I installed this breaker and all the outdoor lines myself just recently. It does trip more frequently than it ought ('course, better safe than sorry). But if I fix this cord, that might eliminate the bulk of the problem.


Today, it tripped while I was in the pool . (I made a big wave that swamped the cord, and off it went.)


Thanks!

 

[Danger]

I installed this breaker and all the outdoor lines myself

Well then, that explains it.

 

[DaveC426913]

Well then, that explains it.

Ouch!

 

[Danger]

.

 

[dlgoff]

The cord is surely electrically leaky. You need to get a better cord.

Try getting hospital grade cableing. i.e. with low leakage current insulation.

Regards