Air Conditioner Breaker trips

[gsxrbox1000]

I've read several of the posts about tripping breakers. Most deal with something close to what i'm experiencing but not quite. I have a 5 year old split system with 5 year old and breakers in a 5 year old house. As I understand it, this is all relatively new gear. The problem is that when i start the a/c unit, the it will begin its startup cycle then the breaker trips about three seconds into it. I removed the inspection cover and everything looks to be in order with no corrosion or foreign debris to speak of and all connections tight with no discoloration. The fan spins freely with very little resistance and the compressor shakes a little and sounds much like the next door neighbors unit. I've read about newer systems being tighter and drawing more current, older breakers tripping more easily and faulty starting capacitors. Where should i start.

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[Ken]

You could have a weak breaker, but you might also have a wrong value breaker installed. (I know, the person installing the breaker and wiring it should have installed the correct breaker.) I think I would first check the installation instructions for your units and compare your current breaker's value to the required one. If it is incorrect, then I would have the gauge of the wire installed for the breaker checked to see if the proper value breaker can be installed.

If the breaker value was correct, I would replace the breaker with a new one. This is a lot cheaper than calling out a technician for the unit.

As others have said, you could also have a problem with your units. For that I would call someone with the proper tools to measure the current draw.

[jamesgangnc]

Has it worked at all this year? Does the fan startup? It's either that the breaker is bad or the compressor is not starting. If you don't have a clamp on amp meter then the easiest thing to do is to replace the breaker. If it still trips then thr compressor is having problems starting. You really need soem test gear at this point. It may or may not have a start capacitor. It will have a run capacitor. You can try replacing that as well. If your neighbor is very friendly and has the same unit then you can try a cap from his.

[Tony]

No way would I ever do that. Ten years later when his unit dies you know it will be your fault.

[bud--]

It is a motor circuit. The breaker can be larger than the wire rating. The breaker provides short circuit protection. The overload protection is at the compressor. Wire and breaker sizes come from calculations.

[jamesgangnc]

While it's possible that the wrong sized breaker was installed it's rather unlikely. It has been working for 5 years. No harm in checking that though. The paperwork with the unit should tell you what size breaker it should be on. It sounds like it trys to start for an unacceptably long time. I also agree the overload protection at the compressor should be kicking out before the breaker though. I'd be confirming that the outside fan comes on right away and listening to also confirm the compressor is trying to start. You can usually tell just from the sound. Without test equipment though about all you can do is replace the cheaper parts and hope you get it. And maybe add a hard start kit but it being only 5 years old does not make it likely that hard start kit will fix it. It also wouldn't hurt to check all the connections from end to end. A bad connection can lower the voltage and make it harder to start. Particularly if it's a really long run form the main panel. Run cap, breaker, and start cap if it has one will all be around $10 apiece. If the run cap is a combo it might set you back a little more. If ir has never run at all this season that does make a frozen compressor a little more likely.

Admittedly it would be a special neighbor that would let you swap parts for testing. Probably pretty unlikely.

[Jon Danniken]

Yep, that's why I neither lend nor borrow tools. BTDT

Jon