Newly installed GFCI constantly tripping


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Old 03-06-11, 07:44 PM
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Newly installed GFCI constantly tripping

First let me apologize if I get any terminology wrong....I recently had a GFCI installed in my unfinished basement as part of getting a plumbing project up to code. I previously had a standard duplex outlet that had the sump pump plugged into the lower receptacle and a 3:1 converter plugged in the upper receptacle which then had both the washer and dryer plugged into it. Not ideal, but it's what I had to work with.

I recently had to update my sump pump and since it was plugged into a non-GFCI outlet, I decided to put in a fourplex box with 1 duplex GFCI and 1 duplex standard off the GFCI. The work was done by a liscensed electrician with 35 years of experience and high ratings on my local Angies List.

It has been one day and the GFCI has tripped a minimum of 6 times. This really worries me as my sump pump is plugged into it. With all the snow we have had in Minnesota this year and with spring coming, I need it to be working all the time. I do have another non-GFCI receptacle I can run an extension from, but that kind of defeats the purpose. I can't imagine it is the load on the circuit as it never tripped the breaker in the past. It runs off a dedicated 15 amp breaker to a junction box in the basement which then runs to two seperate outlets.

Any thoughts or suggestions would be appreciated.
 
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Old 03-06-11, 07:51 PM
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Try to start to see what item is causing the GFI to trip. Remove all but one item and see if it trips. If not try another device until you find what is tripping the GFI.
 
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Old 03-07-11, 03:39 AM
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Do as Jim said regarding testing for the ground fault, as you obviously have one or it wouldn't trip. But to clarify, the GFCI will trip at a much lower amperage (milliamps) imbalance between the hot and neutral. The breaker will only trip when an overload or dead short occurs.
Something you have, and my bet is the pump, is causing the fault. Carefully check the wiring on the pump. If the wiring is OK, and you determine it is the pump causing the fault, it could be excessive arcing in the armature causing it. Let us know what you find out as to the root cause and we'll go from there.
 
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Old 03-07-11, 12:45 PM
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Thanks PCBoss / Chandler...

Per your suggestions, I unplugged all three (sump, washer & dryer) last night at 10:00pm after doing a load of laundry. The GFCI tripped while the washer was filling but then ran the cycle for both washer and dryer without tripping again. I unplugged all three and it has now gone 16 hours without tripping.

When it gets to 24 hours tonight, I'll plug either the washer or dryer in and repeat until I figure out the culprit. If, as you suspect, it is the Sump, I assume I should plug that in last so that I can eliminate the other two first.

If it turns out to be the sump pump causing it to trip.....I assume that means there is an issue with the sump wiring and not the capacity of what I have it plugged into..correct??

I'll follow-up in a couple days when I have found the culprit. Thanks!!!
 
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Old 03-07-11, 12:58 PM
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GFI's do not trip based on ampacity or capacity to use your words. That is the job of the breaker in the panel. GFIs trip when they sense an imbalance in current between what is going out on the hot vs what is coming back on the neutral. Any more than 4-6 mA causes the GFI to trip.
 
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Old 03-09-11, 11:23 AM
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As of the 2008 NEC, sump pumps are required to be on GFCI protected receptacles. Previous versions had an exception to optionally allow the pump on a non-GFCI receptacle, so many existing installations are grandfathered if left as-is.

If the sump pump is tripping the GFCI that means that water has gotten into the sealed motor compartment such as through the shaft seal going bad or the motor windings are going bad. In either case the pump should be replaced.

There are water pressure powered and battery powered backup sump pumps one could install if flooding was a major concern during a power outage. The GFCI tripping is really no different than a tree limb falling on the power line. If you have a substantial risk of flood then it makes sense to install a backup pump instead of a non-GFCI protected sump pump.
 
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Old 03-09-11, 12:09 PM
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All,

I spent the last two days troubleshooting the culprit and it is certainly the sump pump. Both the washer and dryer were plugged in separately for 12 to 18 hours without tripping the GFCI. I plugged in the sump pump this morning and it was tripped by the time I got home for lunch (~4 to 5 hours).

IBPOOKS mentioned deteriorating shaft seals or bad motor windings. Now that we know it is the pump for sure....is the consensus definitely that a new pump is in order? Can I rule out calling the electrician back and just go with the plumber?

Too bad since I just had the plumber out and he asked me if I wanted a new one installed. Guess I should have had the electrical done first and I would have known there was a problem with the pump?
 
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Old 03-09-11, 12:14 PM
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New GFCI

I recently had to update my sump pump
This sounds like the pump would not be the problem unless it was rebuilt.

Did the electrician test his work after he installed the GFCI?

Look for a short circuit in the new box.
 
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Old 03-09-11, 12:14 PM
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The guys over in the Plumbing forum should be able to help you DIY it and you can come back here if you need help with the electrical hook up.
 

Last edited by ray2047; 03-09-11 at 01:46 PM.
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Old 03-09-11, 12:29 PM
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The electrician did test his work and there were no issues. I watched him do the install and testing. I trust both the elect & plumb contractors I had (especially since they were basic jobs), so I have to assume that it is the pump. Over 4 days of testing it has only tripped with the sump plugged into it.
 
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Old 03-09-11, 01:04 PM
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To me it sounds like a sure case of the pump going bad. It could be something simple like the pump cord has been scraped up on the concrete or something like that, but I don't think that even that is repairable. Sump pumps are sealed, non-serviceable so a quick replacement is probably the answer.

These are usually very easy to DIY. Pull out the old pump, drop the new one in the hole, hook up the pump discharge to the fernco adapter, and set the float height.
 
 

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