[DarkFlames]

Hello all,

I have a circuit with a 15 A GFCI breaker that powers a single outdoor receptacle. I have been trying to run a small pump (2.2 A) and the breaker would keep tripping. I elected to replace the receptacle and cover since both looked worn out. The replacement would also allow me to look at the wires. The wires all looked good. With the new receptacle wired in and the pump plugged in, the breaker will trip after a few seconds of being energized.

Testing the receptacle with various loads, I noticed that 2-prong appliances work fine. Even the power-hungry 1875 W blow dryer. As soon as I plug a 3-prong cord, the breaker trips.

Something is not working with the ground? How can the problem be further diagnosed and fixed?

Thanks much.

 

[Oso954]

What make/model is the pump ?

What other 3 prong cord devices have you tried plugging in ?

Are you plugging them directly into the receptacle, or is there an extension cord being used ?

 

[DarkFlames]

Thanks for the reply Oso954.

The pump is a Mastercraft 1/4 hp that is doing just fine when I plug it in any other receptacle.

I just plugged in work lights (3 prongs) without tripping the breaker. The small Stanley shop vac also worked without issues.

Could that small pump draw more than 15 A at startup?

 

[Oso954]

The GFCI doesn't trip on overcurrent, it trips on current leakage.
A non-GFCI receptacle does not sense current leakage. If that is what you mean by other receptacles, it does not mean that the pump is fine.

Since you didn't supply the model number, I am assuming that this is a submersible pump, either a sump or utility pump. It is not uncommon for these pumps to have GFCI problems, particularly with the lower cost units.

I believe that your pump is defective, leaking more current than the GFCI trip point.

 

[DarkFlames]

Pump is submersible utility pump P/N 062-3580-2. Definitely a low-cost unit.

Thanks for the explanation. I thought that by coincidence I may have plugged the pump in a non-GFCI receptacle that would have been on a 20 A circuit.

I will have to see if I can borrow my neighbor's pump to see if it will work.

 

[DarkFlames]

Well Oso954, you are correct. I just tried plugging the pump in a GFCI receptacle inside the house and it immediately tripped.

I was blaming the wrong thing all along.

Thanks for the help. I will go to bed a little less dumb tonight.

 

[Fix'n it]

now that the issue is resolved. i am going to jack this thread, kinda.

The GFCI doesn't trip on overcurrent, it trips on current leakage.

could you please explain this in a little more detail ? the leakage part.

i have an outdoor gfci. and many times it trips when something, even just a good extension cord, is plugged in. once reset all works fine.
i did replace the receptical and same thing.

thanx

 

[elec_2014]

As clarification, and correct me if I am wrong but the OP in the first post mentioned "GFCI Breaker" not receptacle. So in this case if the pump were pulling more than the 15 amps it would trip the breaker (GFCI breaker) or even a regular breakrer and it would also trip it if there were a ground fault any where in the wiring between the breaker and the outlet itself.

Is the OP sure that the breaker is a GFCI breaker or a regular breaker and just mixing terminology as in the rest of the thread the GFCI is now being referred to as a receptacle and not a breaker.

Fix'n it:

could you please explain this in a little more detail ? the leakage part.

A GFCI breaker or GFCI receptacle will trip when it senses a current leakage of between 4 to 6 miliamps. This could be due in this case that the pump (motors cause this) is worn. The GFCI (through its electronics internally) measures the current going out on the hot wire and measures the current going back in on the neutral wire, if there is a current imbalance of between 4 to 6 miliamps it will trip indicating there is a ground fault.

 

[DarkFlames]

The OP was indeed referring to a GFCI breaker. The pump was then tested on a GFCI receptacle.

The only inaccurate statement in my initial post is the 3-prong appliances that would trip the breaker. At that time, the tests were all with the pump, with and without extension chords. Later tests with other 3-prong loads support the defective pump theory.

Thanks.

 

[Oso954]

could you please explain this in a little more detail ? the leakage part.

The official definition is current that escapes the current carrying conductors and returns on the ground conductor. I was using it a little looser than that, to cover all escaping current that does not return to the GFCI, whether it returns on the ground conductor or takes some other path.

I am not sure why you are tripping the GFCI when plugging into it. But if it is resetting and holding without tripping in use, you are not experiencing a continuous leakage problem above the trip point. So it is safe to use.

 

[Fix'n it]

thanx guys. i think i get it now.