Air Conditioner - 15 amp breaker

[CaptDan]

Perhaps I'm misunderstanding some simple electrical concept, however, if my air conditioner's starting current draw is around 59 amps and the "running" amps is 12-18, why doesn't the Grand Design installed 15 amp breaker trip every time I start the A/C? Why isn't the 50 amp main breaker tripping? Additionally I have read that breakers are only 80% efficiency - therefore a 15 amp breaker should really trip around 12 amps (?) The only 20 amp breaker I have is for the Washer/Dryer outlet.

[ncitro]

CaptDan In electronics terms a circuit breaker is a relatively slow device. It depends how far over the rating is, but the basic idea is the breaker (and the wiring it protects) can handle the inrush current from the air conditioner compressor coming on. By the time the breaker is in danger of tripping the current draw has dropped down below 15 amps. The long term running amps should be below the breaker size. I am not sure what AC unit you have, but the Coleman Mach 15 draws max 14.3 on low and 15 on high.

Now on top of all that, my rig has 20 amp breakers for both A/C units, but that could be due to the specific ones I have.

[CaptDan]

Neil:
Thank you.
That makes sense.
We have 2020 397.
Still kinda wondering why GD put 15 amp breakers for all 3 ACs (and others) and perhaps I should upgrade to 20 amps.
Fortunately they haven't been tripping; so maybe I'm over-reacting. Maybe I should go direct to GD and ask.
I only noticed this issue when doing a complete review of my inverter's "pass thru" and "Load support" capabilities.
Thanks
Dan

[Jkwilson]

The 80% “rule” is nonsense. Some breakers won’t trip until 10% over, some are really close. But none trip at 80% of their rating. Some rules of thumb for electrical system design call for 80% with big surges, but if your breakers are 15A, they are not going to trip at 12A. Your ACs likely draw around 13A and are absolutely fine with 15A breakers.

[CaptDan]

John:
Thank you. Since I haven't been tripping the 15 amp AC breakers, I assumed there had to be some
reason the breakers were not tripping.
Dan

[TucsonJim]

Interesting. I have two Dometic AC's on my 2017 model. Both of them them are protected by 20 amp breakers.

Jim

[CaptDan]

You are now the second reply which utilizes 20 amp breakers.

I was able to find a photo of my Airxcel 15000 A/C where I had a Easystart installed (see attached).
if you look at the bottom of the last table it appears to show the minimum circuit breaker to be used (?)

This unit has a heat pump. If I'm reading the sticker right this unit should have had a 20 amp breaker installed
with the Heat pump option (?)

[TucsonJim]

GDRV-Megan

Hi Megan - Can you please have one of the technical folks look into this thread. Dan has a Momentum and his VIN is listed on his profile page. Since he has a heat pump version of the Air Command AC installed, shouldn't his breaker be 20 or 25 amps, and not 15 amps?

Thanks,

Jim

[Calbar]

You are now the second reply which utilizes 20 amp breakers.

I was able to find a photo of my Airxcel 15000 A/C where I had a Easystart installed (see attached).
if you look at the bottom of the last table it appears to show the minimum circuit breaker to be used (?)

This unit has a heat pump. If I'm reading the sticker right this unit should have had a 20 amp breaker installed
with the Heat pump option (?)

I would tend to agree with you based on the information from the tag that you should have at least a 20 Amp breaker but if you have been using it including the electric heater and it has not tripped the 15 Amp breaker I would not bother changing it. Based on the numbers the heater circuit with fan will pull a maximun of 15.6 amps but probably less so the 15 amp breakers are working as they should since this would be a worst case max. I would not change it unless you start tripping breakers. Nothing wrong with the way it is done from the looks of it. Manufacturer says 20 Amps to avoid tripping a 15 amp breaker on the units that pull the worst case amperage using the heater as noted on the sticker.

Rob

[CaptDan]

At least if my heat pumps starts tripping at some point in the future, I'll know why.
Thanks all

[JBill9694]

Let us all remember that the breaker protects the wiring upline of the breaker, not the device downline. The concept is that the breaker will trip before the wire gets to hot to cause damage. Before switching from a 15 amp to a 20 amp breaker make sure that the wiring has enough capacity, and the proper installation to handle the 20 amps.

[TucsonJim]

Let us all remember that the breaker protects the wiring upline of the breaker, not the device downline. The concept is that the breaker will trip before the wire gets to hot to cause damage. Before switching from a 15 amp to a 20 amp breaker make sure that the wiring has enough capacity, and the proper installation to handle the 20 amps.

Excellent point John. The minimum wire size for a 15 amp circuit is 14 AWG. For a 20 amp circuit it's 12 AWG. Placing a 20 amp breaker in a circuit with 14 AWG wire is not correct.

Jim

[CaptDan]

Only have one 20 amp breaker. I am now curious to see if that circuit wiring is different from the others (i.e. 15 amp).
Hopefully all circuit wiring is 12 AWG (or better).

[ncitro]

Let us all remember that the breaker protects the wiring upline of the breaker, not the device downline. The concept is that the breaker will trip before the wire gets to hot to cause damage. Before switching from a 15 amp to a 20 amp breaker make sure that the wiring has enough capacity, and the proper installation to handle the 20 amps.

Yes I was going to make this point as well. Both my AC units have 12 gauge romex run to them so the 20 amp breaker is appropriate. If you’re familiar with electrical work it should be easy to pull the cover off of the breaker panel and see what size wire goes to the AC circuits.