NO! You may not replace a 20A breaker with a 30A.

I would suspect some type of wiring problem, primarily because your "electrician" did not follow NEC guidelines when wiring the shed: You are limited to a single branch circuit (or multiwire circuit) to a detached building. Anything more requires a feeder and a subpanel. If the electrician violated that, what else might he have done wrong?

You got some things to look at first like is the underground wire sized for the 30 amp breaker it has to be a ten wire...or no deal. The other thing i would look at since you are tripping a breaker is the load on that one that trips. It should not be more than 16 amps. The other concern I would have is what kind of underground wire was ran if it is 2 12-2 uf wires or a 12-3 uf wire or what.. because if you have a breaker that trips but not because of the current being too much then you might have a cut in the wire underground that only trips when water gets into the circiut because of all the rain you are getting. It would act like a short and trip the breaker. Just some things to check first.post back with more info..JD out.

Okay, I get the message. Think the best thing I can do now is get another electrical co. in here to pull a QA and tell me what's wrong. I have too much to lose to throw caution to the wind.

Thanks.

Normel: Not trying to pick an argument here, but it seems to me that the "electrician" may have installed a perfectly good multi-wire circuit....two breakers, one cable (12-3 with shared neutral?) with the lights on one pole, the outlets on the other. Setting aside the issue of whether the two breakers should trip together via tie handle or a two-pole breaker (and I don't want to start that debate again), what is it about the OP facts that suggests an NEC violation? I dunno, just curious.

Sounds to me like this could be a more basic "tripping breaker" problem having nothing to do with poor wiring or thunderstorms.

Are there any other loads on that receptacle circuit? Could the GFI outlet be filling with water? (Note that if a short occurs on the line side, it won't necessarily trip the GFI.) Are you confident that the fridge itself isn't the problem regardless of what outlet is used? Has it been demonstrated to work on another proven circuit without problems?

Normel: Not trying to pick an argument here, but it seems to me that the "electrician" may have installed a perfectly good multi-wire circuit....two breakers, one cable (12-3 with shared neutral?) with the lights on one pole, the outlets on the other. Setting aside the issue of whether the two breakers should trip together via tie handle or a two-pole breaker (and I don't want to start that debate again), what is it about the OP facts that suggests an NEC violation? I dunno, just curious.

Unless the panel is an old Pushmatic, putting the breakers on the left and right side of the panel says to me two circuits. If he ran a multiwire and oriented the breakers this way, then he is still wrong, as this doubles the load on the neutral by putting both hots on the same hot bus.

Normel:

Thanks for replying--I understand where you're coming from.

I guess it still isn't too clear to me what the OP means by "hooked up with a 20a breaker on the left side and a 20a breaker on the right side". I don't know whether that means the breakers are on the same pole, exactly to the left and right of each other on opposite sides of the panel.

My preference for MW cc's (and code now, I believe, in those jurisdictions using new NEC version) is to use two-pole breakers or, at least, to use handle ties. That more or less ensures the breakers are not on the same pole and also means the neutral won't be carrying current when one but not both of the breakers are turned off. But it's an issue that's come up before in this forum and there are at least a few sparkies here who argue that sometimes a feller's gotta put the breakers where slots permit, so long as he's sure they're not on the same pole.

I think this OP's probably gone now, but I did want to raise the possibility that the overall wiring may be OK, but there's another garden-variety reason a breaker is tripping now and then. It seems to me that's at least as likely as concluding an electrician totally bungled the job. And while I agree that a miswired multiwire circuit can lead to an overloaded neutral, that's not likely to be the cause of the intermittant breaker tripping, given the infor provided in the post.

I dunno. YMMV.

Thanks again and cheers,

Tom