I have an outdoor fountain with a pump that is pluged into a new outlet next to the pump. I connected that outlet to an outdoor switch on the porch so I can turn the punp on and off without going to the fountain.

I taped into an existing outdoor outlet on the porch and put the switch next to that.

The problem is whenever I turn the switch on, the pump will turn on for about 5 seconds or less and that trip the GFI.

I thought it was the pump, so I removed the pump... nothing plugged into the outlet by the fountain. I flip the switch and the GFI trips.

After replacing outlet by the fountain and making sure there was no mositure and nothing plugged in... I flipped the switch and it still triped the GFI.

I replaced the switch and everything worked... the pump ran for 1 day... I shut it off that night. The next day I turned it on and it triped the GFI again.

IT appears that replacing the switch fixed it for a time, but now I am back to it not working... what should I be looking at to solve this problem?

Without knowing more detail of the circuit design, the following can cause a GFI to trip:

1.The neutral wire touching the ground wire somewhere in the circuit.
2.The wiring if underground in a wet conduit
3. Long circuit lengths.
4.If the switch is not a good grade and/or located in a wet location .
5.GFI may be defective.

2B Buried non metallic that wasn't rated UF. When I worked for a wire and cable company, I am not sure they changed anything but the print wheel in going from grade to grade of non metallic. Each grade was inspected to assure it passed what it was labeled for.

I knew what I meant in my above post, but others didn't. I started as 2B to suggest a supplement to tkrussel's point on water in a conduit. I wanted to add the possibility of a non metallic cable leaking enough power to trip a GFCI. I then went on to discuss some of my past experience in a company that manufactured cable. At that time cable was labeled for different uses, each with its own spec. I think the same stuff went into all the non metallic cable. They just changed the wheel that printed the information on the wire.

None of their building wire had a brand printed on it, only a UL code. That way they could change brands by changing boxes.

This is a 15 amp circuit. Basically I had an outlet on the front porch that I taped into with a 25 foot run underground. The end of the run has a 15 Amp 3prong outlet with a Red Dot waterproof cover over it. Where I taped into the outlet on the porch is a switch so I can turn the run on and off. I have a small water pump plugged into the outlet at the end of the run for a fountain.

The GFI trips just turning the switch on... without the pump even plugged in...

1.The neutral wire touching the ground wire somewhere in the circuit.

If this were the case, would it be typical for it to work for a day - 10 - 12 hours and than not work the next day or since than?

2.The wiring if underground in a wet conduit

The wiring is underground... it is not in a conduit but is underground rated. I live in souther CA, so it is pretty dry here... has not rained in a while. Some dew in the mornings, but gets warm enogh to dry everything.

3. Long circuit lengths.

This only adds about 25 feet to the circuit... I don't know how long the entire circuit is. But the GFI is actually in an upstairs bathroom.

4.If the switch is not a good grade and/or located in a wet location .

I bought a new 15 amp switch at Home Depot and is was marked as "best" quality.

Again... once I replaced the original switch, the circuit worked for a day. The original switch was just something I had laying around the garage... that is why I bought a new one.

The switch is not in a wet location and uses a Red Dot outdoor switch cover.

5.GFI may be defective.

I replaced the GFI

Well you sure did address each item I have listed. Don't you just hate when a simple job turns out to be a nightmare?

What you have done shlould work fine. There must still be something causing the GFI to trip. Does the feed go to the switch first, which I assume is just inside?

Or does the feed go to the GFI then to the switch, then a switch leg back to the GFI?

Not sure why I am asking, trying to get a sense of how the existing wiring is run, and see what wiring is GFI protected and which is not. I assume whatever was there worked fine until you added the 25 ft run. There can be a small nick in the UF cable, or something touching at the new pump outlet. About the only thing you did not change is the new cable.

I am not sure how difficult it would be to change the cable, but it may be the olny thing you can do. UF cable is very tough , really can take a beating without causing any problems. But unless you can find something touching at the GFI outlet, the switch, or the new outlet, I am not sure where else to go.

OK I finished re-reading your last post, GFI is on 2nd fl bathroom. This is the actual GFI device that has the test and trip button, this must protect other outlets downstream, this means the cable runs through the home, may hit another GFI in or out the home, go through the switch and end at your porch outlet, correct? Even if this a long run, adding 25 foot should not be the problem.

If disconnecting the new outlet allows the switch and porch outlet to operate fine, and then trips once the new outlet is connected, the problem must be either how the new conncetions are made, the new cable, or the new outlet.

I hate to say it, but back to the drawing board, got to replace the cable. The only hope you have is findinga poor or incorrect connection where you connect the new cable.

Wish I could be of more help.