Pool tripping GFCI breaker

[killavolt]

A friend of mine has an inground pool. The last few days the pump has been tripping the GFCI breaker. He reset the breaker and the pump would run for a while and now the breaker won't reset. He replaced the pump, I replaced the GFCI breaker, making sure the neutral load was installed on the correct terminal of the GFCI and that the line and neutral were correctly wired in the panel. I replaced the twist lock receptical, with a 20A 125V (same as before) and the 20A switch. I also replaced the bubble rain tight cover as the gasket didn't look as if it was intsalled "rain tight". The GFCI doesn't trip when the pump is not plugged in. The pool and pump are correctly grounded as per NEC code 2008. The pool pump is on a timer if this helps.
Any thoughts as to what could be causing the GFCI to trip? I took the twist lock pigtail off and installed a regular plug on and the pump runs fine (on another non GFCI circuit) . I taped the twist lock receptical and the switch contacts inside the weather tight box as well to make sure they were isolated from adjacent wires. The pump draws about 18A on a 120V circuit, which is pushing the ampacity of the circuit but it has run this way for about 6 years.

[Thatguy]

Disconnect the neutral wire from the load side of the GFCI and check for no continuity between it and the ground wire.
Reconnect the neutral.

Measure the cold resistance of a 7-1/2w incand. lamp. It should be 100 Ω to 400 Ω. Call the value R.
Put the lamp in series with the ground wire that serves the cable downstream of your GFCI.
If the voltage across the bulb reads from 0.004R [0.4v to 1.6v] up to 120vac you've found your leakage path to ground. A normal reading would be 0.0005R for each 100' of Romex downstream of the GFCI.

[killavolt]

This is a GFCI breaker, on a dedicated circuit that serves only the pool pump. The neutral and ground buss bars in the panel are not seperated as this is a main panel. I have continuity between the neutral and ground at the pool's twist lock receptacle. I appreciate you taking the time to answer though.

[Thatguy]

Better search terms might narrow this down.

http://www.google.com/search?hl=en&c..._nhi=&safe=off

[ActionDave]

Try plugging the motor into another gfci protected circut.
Test the pool circut with a load other than the pool motor.

You should have continuity from neutral to equipment ground, they are joined at the service.
If you take the load neutral off the gfci breaker then check for continuity it should read clear.
However if you follow the first two suggestions you may not need to do this.

[killavolt]

Thanks fellas, I'm going over today to have another look. I'll report back with results.

[Chris75]

The motor is probably shot. just a stupid guess though.

[Thatguy]

the GFCI breaker

Can you post a link to the one you are using?

[killavolt]

The motor is probably shot. just a stupid guess though.

Replaced the pump motor yesterday brand new Hayward 1 1/2 H.P. I found where someone tied a lighting circuit into the pool's GFCI breaker circuit twist lock 4' sq. I'm gonna disconnect it and try a new pigtail on the pump motor. Water inside the pigtail could cause a ground fault.

[Chris75]

Replaced the pump motor yesterday brand new Hayward 1 1/2 H.P. I found where someone tied a lighting circuit into the pool's GFCI breaker circuit twist lock 4' sq. I'm gonna disconnect it and try a new pigtail on the pump motor. Water inside the pigtail could cause a ground fault.

1.5 hp motor at 120volts? highly doubt it.

[PEW]

Don't doubt, it they do exist. I have a gould irrigation 2hp running on 120.

[Scuba_Dave]

1.5 hp motor at 120volts? highly doubt it.

My pool pump is 1.5 hp & is switchable from 120 tp 240v
At 120 it was rated for 18.6a Max - also a Hayward
So I wired it for 240v

[Thatguy]

I found where someone tied a lighting circuit into the pool's GFCI breaker circuit

So for GFCI breaker problems the first thing to check for is bootleg wiring.

[Scuba_Dave]

Actually all of the lights near my pool & in the pool cabana are GFCI protected

But my pump is on its own circuit - now 240v
Mine is rated at 18.6a @ 120x, so that only left ~168w for anything else
So with a 150-300w flood light running that could kick out the 20a breaker

[jadnashua]

No CB should be loaded that high with a continuous load. You risk it potentially tripping regardless if there's a problem or not. Is that amperage the peak start current, or static while running?