Do Breakers Get Old/Tired?

[Silver Otter]

'99 Excella with 13.5 A/C blows its breaker in every camp situation so far. At first we attributed this to "bad power" in a less-than-wonderful site.

This problem, from records from the PO, goes back some time. We asked JC to check it, but Paul found no problem. We bought a

Progressive Industries 30 Amp Portable Electrical Management System

so we can read the voltage and amperage feed in real time. It reports between 117-127 volts and no more than 19 amps being pulled. We've tried turning everything else off, including the fridge and water heater, and it still blows.

It is time to replace the breaker because it's old and tired, or am I missing something else critical?

[HowieE]

Yes breakers will age.

That said the management system you bought is monitoring the complete trailer AC system and not the air conditioner alone.

Try turning off all the breakers except the one feeding the Air C. Now read the current that the Air C. draws by itself. A breaker is designed to blow at 80% of its rating. If the breaker is blowing at less that that I would replace the breaker as a first step.

The air should only pull about 13 amps. If it is pulling more than that you may have a problem in the Air C. itself. If that is the case you would have to do a draw test on the fan and the compressor each to see where the problem is. That will most likely require a Tech.

[Jim Clark]

Breakers get old and the springs get weak and they fail early. Do what HowieE states but also clean all the connections until they shine. Be sure all power is disconnected from trailer and do one connection at a time and reconnect before disconnecting the next. If you can get too the connectors on the AC clean them all including the compressor.

Jim

[Silver Otter]

Great advice, guys. Thanks. We'll do the checks this weekend. When you "clean" connections, what tools/materials are best to take along?

[Mr.Bill]

Rubber eraser if they aren't too bad, emery paper if they are.

[Gene]

Breakers are cheap (usually, but not if they are Zinsco). Like us, they get old and hypersensitive. Buy one, change it, if it works, problem solved. If not, you have a spare. Or, if all the breakers are the same amps, switch one with the A/C breaker, and see what happens.

Gene

[HowieE]

As far as cleaning Spade Connectors is concerned just making and braking the connector on itself will clean the point of contact. These connectors also can relax over time so make sure each connector goes on with good resistance. If one seams looser than normal you can crush the sides slightly with pliers to reload it or if real weak and color changed from over heating replace it.

Poor connections will increase the current but I suspect you have a weak breaker.

[Excella CM]

Sometimes you will find a ground-fault breaker installed, which, if you have one, can be either defective or actually detecting a fault. Also, I believe everything gets old and tired (this I know from direct experience).

[casa3805]

Originally Posted by CrawfordGene

Breakers are cheap (usually, but not if they are Zinsco). Like us, they get old and hypersensitive. Buy one, change it, if it works, problem solved. If not, you have a spare. Or, if all the breakers are the same amps, switch one with the A/C breaker, and see what happens.

Gene

Gene is right. Breakers are cheap (unless it is a GFCI) mine are GE and they do get old and tired.

[Silver Goose]

I think we're in agreement that breakers age and can trip prematurely. As stated earlier, cleaning and tightening the connections can be beneficial. An oxidized or loose connection generates heat and the resistance of the poor connection reduces voltage to the load. As a result, the load draws more current further increasing the heat. The added heat alone can push the breaker to its tripping point.

My 13.5 A/C was inexplicably tripping its 20A breaker regularly on warm days. Line voltage was staying above 115V. The service manager at a local RV shop asked if I had a 30/20A combo breaker with the A/C on the 20A half which was exactly how my box was wired. The 30A is the main breaker, and the 20s are the branch breakers. He suggested I move the A/C line to a different 20 away from the 30 and put a lesser load on the 20 side of the 30/20 sandwich. His belief was that the heat transfer between the physically connected halves was causing the 20 to trip prematurely. I put it to the test 2 weeks ago on a 110+ degree weekend and none of the breakers ever tripped.

I see one of three fixes here (or a combination of any): The 20 half of the combo breaker is weak and isn't tripping with the reduced load. The act of swapping the wires resulted in a clean tight connections. There is a possible problem of heat transfer when the A/C breaker is sharing the body with the main line breaker.

[Silver Otter]

Very interesting, YankeeD. Mine's wired the same way. I'll get at this this weekend. THANKS.

[Jim Clark]

A added benefit is just the act of moving the connection will also clean it somewhat.