Sewage ejector pump intermittently trips GFCI breaker

[mangoManFT]

I have a Liberty sewage ejector pump outside my house. It is plugged into an outside GFCI outlet. Intermittently, the GFCI breaker trips and the pump doesn't run. If I reset the breaker, the pump runs again. There doesn't seem to be any particular event that triggers the breaker trips, as far as I can tell. Sometimes it trips once a day, sometimes it's fine for a week. I thought it was the GFCI outlet receptacle itself, but I replaced it and the trips are still happening.

The pump was installed 8 years ago. It is a Liberty P372LE51. It has never been serviced, but the manual doesn't state any recommended periodic maintenance.

What could be causing the GFCI trips? Could a clogged impeller cause a GFCI trip? I have not opened up the pump to check the wires, so I suppose that somehow one of the wires could be shorting with fluids in the chamber. Or is it a sign the pump is going bad? I hoped this would last longer than 8 years. It only services one bathroom and our kitchen sink/dishwasher.

Any comments/advice is appreciated...thanks!

 

[Reach4]

Measure the resistance from the power wires on the pump to ground wires. A resistance than about 24000 ohms (24 kohm) would be about the border between tripping and not.

Myself, I would consider rewiring in a way where no GFCI was needed. I think that hard wiring the sewage pump directly, with no outlet, might do that. I am not an electrician.

 

[Sponsor]

 

[mangoManFT]

Measure the resistance from the power wires on the pump to ground wires. A resistance than about 24000 ohms (24 kohm) would be about the border between tripping and not.

Myself, I would consider rewiring in a way where no GFCI was needed. I think that hard wiring the sewage pump directly, with no outlet, might do that. I am not an electrician.

Thanks, I'll check that resistance. I also had thought about rewiring the outlet to make it non-GFCI, but the outlet is also outdoors, and to be to code it needs to be GFCI.

[edit] Just re-read your post - yes wiring directly (no outlet) is possible, but not sure about code issues.

 

[WorthFlorida]

With direct wire a cutoff switch would be needed near the pump so the pump can be serviced. GFCI are needed for outlets where you can accidentally be shocked with power cords for tools, extension cords, etc.

A long winded article on disconnects.
https://www.ecmweb.com/code-basics/disconnect-requirements-articles-422-through-450

 

[mangoManFT]

Forgot to follow up on this thread. I ended up re-wiring the two outlets I had in my exterior box such that one is non-GFCI protected and the other is GFCI protected. I plugged the pump into the non-GFCI outlet and the alarm in the GFCI outlet, and all seems well. Before, both outlets were protected via the same GFCI, so when the pump tripped the GFCI breaker, the alarm lost power and didn't sound. Now if the pump fails the alarm should still have power. Unfortunately I never discovered what was causing the pump to trip the GFCI breaker.