Sump Pump nuisance trips GFI

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AZsparky

AZsparky

Senior Member
Location
Scottsdale, AZ
Client has outdoor 120 volt (factory corded for plug'n play) sump pump for patio area drain tiles that trips its (well protected) GFI when heavy rain occurs...exactly when it's needed, but does NOT when tested with garden hoses simulating rain and water accumulation. What are my options under code? I know I could cut cord and hardwire to switch as means of disconnect, but there goes pump listing and warranty and here comes code issues. TIA for any thoughts on this...
 
Thanks for your reply Jumper. All options you mentioned were as I thought, but anyone know of a GFI that is less prone to nuisance trips? Are the WR ones any better for this?
 
Thanks ptonsparky

Thanks ptonsparky

Pretty confident that there is no moisture getting to the GFI plug/receptacle area, but will check. I have surface mounted Bell box caulked where it contacts the structure and using in-use cover that totally latches with plug inserted. Might try WR GFI or probably just tell client to get new pump. Been out there before for same problem...Line side of GFI is buried UF cable (installed by others some time ago), but GFI should only trip because of any loads attached to it right? Small line side circuit fault should have no effect on GFI tripping, right?
 
NEVER had a line side leak trip a GFI

NEVER had a line side leak trip a GFI

I'm pretty sure that only a load side current imbalance can trip a GFI. The measurement CT is only supposed to be measuring across the load to my knowledge. So, I think I'll replace the GFI with a WR type and if it continues, it will have to be new sump pump time for this client. It's only his patio which gets water collecting on it, not a basement situation where big damage could occur. and in AZ, it's only once in a great while here. But he did pay me to provide a receptacle for the outdoor corded sump pump 2 -1/2 years ago. Second time this has occurred.
 
I would definitely go with a WR GFCI, but while it was disconnected HV megger the UF, after making sure the loads are disconnected also.

I had a 100 ft buried run of UF trip a GFCI, every time it rained.
 
AZsparky said:
.... when heavy rain occurs...NOT when tested with garden hoses simulating rain and water accumulation..
Click to expand...

So the pump runs and pumps water without tripping GFI, *probably* not a internal pump problem. How accurate was your "simulation" ? Maybe the rain water splattering everywhere is enough to make some part of the cord assembly or recept. wet?
 
Next time it rains, unplug the pump and see if the GFCI holds. If yes, it's the pump or cord. If no, replace the GFCI.

Also you said you caulked the box where it meets the wall. You might want to take the plugs/seals out of the bell box and put silicone (or similar) to seal the opening. I've seen those things leak bad and I think most instructions say to do this.
 
Little Bill said:
Next time it rains, unplug the pump and see if the GFCI holds. If yes, it's the pump or cord. If no, replace the GFCI.

Also you said you caulked the box where it meets the wall. You might want to take the plugs/seals out of the bell box and put silicone (or similar) to seal the opening. I've seen those things leak bad and I think most instructions say to do this.
Click to expand...
Drill a weep hole as well.
 
Does any lightning frequently accompany this rain but not your water hose test?

Makes even more sense that lightning may be associated if the tripping is fairly random, vs it tripping every time it rains.
 
Put a piece of sheetmetal over the cover and see what happens. I usually caulk around the cover and the hole that was cut for the box.
 
Update

Update

THANKS to all who contributed. After my service visit, (original information was given to me by phone via client, although I had been there before two years ago) I discovered that the circuit was being fed from a GFI breaker and the pump was the only outlet on it. I found the breaker in a tripped position, replaced it with as standard 20/1 BR and the pump came on and took the two+ inches of rainwater collected on his patio away in about ten minutes. So, I'm pretty sure that the UF feeder is slightly bad somewhere. Inside the GFI box was dry as a bone, (GFI had not tripped as the client had told me on the phone) and with no sign of moisture inside the enclosure. There will be no easy way to re-feed the GFI as there is 20' of hardscape to get by. And surface mount conduit will look like manure on a white chicken.

So, I apologize for taking the client's word and posting here prematurely. My sincere thanks to all those who took the time to provide possible answers.
 
AZsparky said:
THANKS to all who contributed. After my service visit, (original information was given to me by phone via client, although I had been there before two years ago) I discovered that the circuit was being fed from a GFI breaker and the pump was the only outlet on it. I found the breaker in a tripped position, replaced it with as standard 20/1 BR and the pump came on and took the two+ inches of rainwater collected on his patio away in about ten minutes. So, I'm pretty sure that the UF feeder is slightly bad somewhere. Inside the GFI box was dry as a bone, (GFI had not tripped as the client had told me on the phone) and with no sign of moisture inside the enclosure. There will be no easy way to re-feed the GFI as there is 20' of hardscape to get by. And surface mount conduit will look like manure on a white chicken.

So, I apologize for taking the client's word and posting here prematurely. My sincere thanks to all those who took the time to provide possible answers.
Click to expand...

Thank you for the follow up. So many times members post a question, get a lot of good replies/suggestions, then are never heard from again.

Sounds like there is an intermittent fault in the UF to the receptacle. So long as there is a GFCI receptacle, you *should* be gtg for now, tho replacing that UF run is in the HO's near future.

"And surface mount conduit will look like manure on a white chicken."

:D:D:D The HO may be ok with it once he's quoted what line boring, trenching , or tearing up his driveway would cost.
 
Yea, hate that exposed conduit in residential.

The circuit only "acts up" after very heavy rain conditions, so here in AZ will probably be good to go again until maybe monsoon season...
 
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