Hey Desk chair quarterback What the f+*# does this say:Troubleshooting a septic pump (less than 2 yrs old) in the backyard- would run for a period of time then trip the breaker in the house. Existing wiring is UF 12-2 directly buried in the ground with no GFI. Before you start slamming people open your eyes and read. And as far as a myers pumps not being a decent quality submersible pump. I guess you would know better than one of the biggest pump manufacturers around. So get on your bike and back pedal some more.
In my original post, I said that plugging in either the float or the pump invidually would not trip the GFI but having both plugged in would trip it. Right now the float is out of the system- only the pump is plugged in.
The original setup was that the pump and float were plugged into the 12-2 UF cable sticking out of the ground terminated with a female cord end (unsealed). The circuit was on a dedicated 20 amp breaker, no GFI protection at all. Right now the pump is plugged into an above ground extension cord that runs to a GFI receptacle in the garage, different breaker than the original pump breaker.
The underground UF cable will be replaced shortly with cable in a conduit and a proper GFI setup when conditions allow.
I'm leaning towards a defective float switch right now.
Don't forget what I said about the contacts on top of the motor where the power and floats plug into,they are probably corroded bad and will break off. You can try replacing the floatswitch whip but I still think the whole pump should be replaced. Don't forget if you are gonna run new UF also run another set for an alarm if it's not already there. And make sure if you use conduit that the ends are sealed so the gases from the tank don't stink up your basement. If you have any questions about the intank or any other setup let me know. Good luck and watch out for the corn.