My pond pump has been operating for over a year. Recently it tripped the gfci. I pulled it and took it apart but didn't see anything obvious. I pulled the ground wire and tried the pump and it worked. Anyone have any ideas?

Motors and GFI's don't always get along. Why do you have it on a GFI?

The gfci was installed by the previous owner. It's been working without any problem for the eight years I've been here.

If it is working now, I would call it a fluke and not worry about it. If something is wrong it will trip again.

Next time this happens, I would check GFI. They go bad quite often, especially when installed outside exposed to the elements.

My apologies for confusing the issue, the gfci is not the problem. When I reset the gfci, it pops again. I've checked it with another gfci plug with the same results.

The pump apparently has a short somewhere. I susected the capacitor so I took the pump apart and tried it with no load both with and without the capacitor with the same results. I then removed the ground wire and the pumped worked. I'm hoping someone will have an idea which will not require me to open the case.

If there is nothing obvious in the wiring connections, I suggest that you have a motor winding that is shorting to the casing. You can check this with a meter but it sounds like its time to take to the shop. A capacitor would not cause this. Do you know how to check a capacitor with a meter?

Guess I'll have to take it in and have the windings checked. Only thing I've seen on checking a capacitor is to check it on the highest ohmmeter setting. If it starts high and then bleeds down it's OK.

Disconnect all wires to capacitor. Set meter to resistance or continuity. Touch meter leads to capacitor terminals. The battery of the meter will place a charge in the capacitor. Reverse the leads and touch to capacitor terminals. If the capacitor is good the meter will show a momentary current flow.

Electricity, like water, takes the path of least resistance; removing the ground wire forces all the current back into the neutral, and that seems to satisfies the GFI.

"Ground fault interrupters are designed to protect from electrical shock by interrupting a household circuit when there is a difference in the currents in the "hot" and neutral wires. Such a difference indicates that an abnormal diversion of current from the "hot" wire is occuring. Such a current might be flowing in the ground wire, such as a leakage current from a motor or from capacitors..."