gfi breakers

[Dirt merchant]

Hello, I recently installed 65 well lights in a yard. There is like 8-9 zones coming back to the house. Some of the zones are around 600' long with a low amperage load. Max zone has 12 25w bulbs. I used #10awg. the zones are split into 2 circuits within the house,neutral are not shared!, but the gfi's are tripping. why?? I switched to a regular breaker and it is fine. I spent a day opening all fixtures and everything is dry and blk/wh/grn. I used GE breakers and read something in the papers about different levels of gfi sensitivity. Any one have any help? I've been through my school books and cant find anything! thank you.

 

[iwire]

Re: gfi breakers

My guess is some moisture and the long runs combined are tripping the GFCIs.

You best bet may be to eliminate the GFCIs all together.

[ January 25, 2006, 01:10 PM: Message edited by: iwire ]

 

[Dirt merchant]

Re: gfi breakers

I search and found no moisture, these are well lights with sprinklers in the yard. I thought it would be a smart safty thing to install gfis. Is it ok to do this insallation w/o a gfi?

 

[charlie b]

Re: gfi breakers

If the lighting units are hard-wired (i.e., not plugged into outdoor receptacles), then you do not need GFCI protection. It is possible that the tripping might be from leakage current from the capacitance to ground of a 600 foot long conductor. But someone (I haven't the time) would have to do the math to determine if this is likely.

 

[Dirt merchant]

Re: gfi breakers

Thank you Charlie. they are hard wired and the "capaccitance" is what I read on the package. If someone can leave me/ tell me where to find the formula I'd love to do the math. I really do love my job and sleep much better knowing things are alright. fyi these are in 3/4" pvc, sealed with potting compound, and used "blue" wirenuts. The only area that is not sealed is the factory socket.

 

[pierre]

Re: gfi breakers

Charlie
I agree with you, that the length of the runs are possibly creating the situation that causes the GFCI breakers to trip. Remember that it is the length of the run out, all of the splices, and the length of the run back to the breaker.

That means of length of 1200 ft of conductor

 

[iwire]

Re: gfi breakers

Originally posted by Dirt merchant:
I search and found no moisture,

In my experience if you have hundreds of feet of underground raceway there is moisture in the raceways no matter how much you try to keep it out.

But as has been mentioned the long runs can kill you as well.

I am going to guess you used THWN, which has a lower dielectric strength than other insulation types.

I believe XHHW or RHW would have been a better choice.

Originally posted by Dirt merchant:
Is it ok to do this insallation w/o a gfi?

Yes it is and may be what you have to do.

GFCIs are not required for lighting outlets.

 

[mhulbert]

Re: gfi breakers

FWIW, I just put in a few Square D QOB GFI's ant they advise of a max one way distance of, I believe, 250'. Youa re well beyond this, and since all GFI's are close in sensitivity, you are most likely tripping due to capacitance.

As Bob said, XHHW would be better for this situation. Your installation is not flawed with THWN, but I think you are going to have to switch to normal breakers. As others have said, GFI's are not required.

mike