Maybe the other circuit has a short to ground causing the trip in the wiring. I.E. your 'spitter' pump is probablly o.k. it is the wiring of that second circuit that is bad.

The fault could be caused by some dampness and only causes a small current to flow. Hence the "tester" shows O.K. but the GFCI still trips because it will trip on a 3-6 milli amp current leakage.

Best, Mike.

Thanks for the feedback Mike.
The problem is even when I switch the pond pump to the other circuit it works fine until I flip the switch on for the other circuit.
Is it possible that the GFCI breaker itself could be bad? Someone told me that these breakers eventually can wear out.

Witz

I suspect that the problem really is a minor ground fault in the circuit. Replacing the breaker is likely to only drain your pocket without solving the problem.

Thanks Dave,
A new GFCI will run me about $55. I would suspect that a licensed electrician is going to charge somewhere in the area of at least $75-100 just to come out and look at it.I hate the thought of having to dig up my wiring, it's all under finished landscaping and I can't remember exactly where the splices were. Will one of those 'multimeters' show if I have a short?
Witz

You have buried splices? I would suspect that is the problem. A GFCI will trip if the neutral and ground are touching, or if there is a small leakage of current from either the hot or the neutral to the ground. there does not have to be a direct short, just 5mA or more of leakage. A new GFCI breaker will not help.

Normel,
There were 2 splices, both done by a licensed electrician and his crew. I would go back to him but this was done back in 2004 and the fellow has since gotten divorced, liquidated the business, and moved.
I am curious as to why this problem wouldn't have shown up earlier if it were a wiring short. Like I said, I didn't have any problems until the end of the 2nd year.
I guess I'm going to have to bite the bullet and get an electrician out here.
Thanks to all for the feedback.

Witz

If the splices were not properly done, and having a licensed electrician do them is no guarantee they were, it could have taken this long for moisture to creep in to the splice and cause problems.

you mention two circuits, but, if you have one GFI breaker you only have one circuit which is feeding

two switches which are feeding

one receptacle with two outlets

Correct so far?

Swap out the receptacle with a new one and be very careful of the way it is wired and the tabs that are broken out to make it seperate outlets.

This is what I would try first because it is the easiest and cheapest. Buy a good outlet that lets you put the wire in the back and then tighten the screw, not a backstab.

Hendricus,

I'm curious as to why you suggest replacing the receptacle. How do you think it's causing a ground fault? Can you explain with a bit more detail?

Thanks.

After reading the OP's description of the problem, either switch and outlet works fine by itself, it is when the other outlet is turned on also, either one, that the trip occurs.
A lot of wiring is going to one receptacle and if the receptacle is pulled it might show crossed wire? stripped wires? bare wires?.

The point is that a new outlet is readily accesible and under $5, something to be tried first IMHO rather than last.

I guess it can't hurt.

It's just that I'm rather frugal, and constitutionally opposed to changing stuff unless I know it's defective. From what I've seen, receptacles don't much fail unless it's either an inability to retain the plug, or a catastrophic failure such as a fracture of the body. Generally if there's something wrong with a recept, you'll catch it right away in a visual inspection.

I had a similar problem with the lighting on the perimeter of our deck. I isolated the problem by wiring each light one at a time above ground using a length of romex. Once I got it to work with the exposed romex. I replaced that section of cable. I found that water had gotten into the cable jacket causing the ground fault.

The only splices we bury are low voltage landscape lighting which use special filled wire nuts. Line voltage should never be spliced let alone buried without conduit. Kill the power, dig the stuff up and run 12ga.braided conductors through pvc romex. I think I know why your former electrician gave up his business.

Correction. Run the braided wires through PVC conduit. You can buy this wire in various colors at Home Depot. Purchase black, white and green. Tape the three wires together and push them through the conduit. The conduit comes in 10ft. sections so you will need how ever many sections and the various connectors and PVC cement. Don't get plumbing PVC, get electrical PVC with the appropriate cement. If you feel uncomfortable with this , hire a competent master electrician. If you dig the trench 6" deep or so, an electrician shouldn't charge you more than a couple of hundred dollars plus supplies.

Line voltage should never be spliced let alone buried without conduit.

I'm not so sure about that. You can buy approved underground splice kits for UF. I've used 'em.

IMO, splices underground are inherently safe - if they fail, there's nothing around them that supports combustion. But safety is not the only consideration. Who wants to dig it up when it quits working?

IMO, line slices underground are inherently unsafe. We don't do it and we always use PVC conduit for underground application. It appears the line splices are causing the OP considerable problems.

Hiring an electrician that has and knows how to use a megger will either prove or eliminate the underground as a problem. Many residential electricians haven't ever used one and get a "deer in the headlights" look when you ask about it. Additionally, the electrician should have a fault locater and know how to use it. Someone who knows how to use a fault locater can often pinpoint a leaky splice and may save you lots of landscaping damage.

Underground splices correctly done with shrink sleeving that has a sealer inside provide a moisture proof splice and are perfectly safe in an otherwise code compliant installation. In residential applications I recommend running conduit specifically because of the issue you seem to be having, but there is no requirement to do so. The MINIMUM burial depth for either conduit or cable IF it has GFCI protection is 12" - - unless under 2" of concrete where 6" is acceptable or under 4" of concrete where 6" is acceptable for direct burial and 4" for conduit unless the concrete is a driveway, then 12" is required. 18" is the norm for burial and usually recommended absent unusual conditions.

I'm not sure what braided wire is for use in conduit but there is stranded wire that is commonly used.

Finally, be sure if you hire an electrician that (s)he doesn't have an issue with you providing material.