Is this normal for a 30 amp breaker

We're talking about TT AC units not household or commercial units. My trailer AC unit is on a 15 amp breaker. If that has a 50 to 60 amp draw at start up, there is something wrong.

LoudRam wrote:
As per NEC you are only allowed to load a breaker to 80% of it's rated capacity that way you have room for start up current. My AC is only on a 15a breaker and draws 10 to 11 amps. A 20a breaker should be more than enough. And as it was stated earlier warm is normal but hot is a problem. However it never hurts to check the connections.

That's not quite right when it comes to motorized appliances and equipment.

An AC unit (and any motor for that matter) has the breaker "over-sized" (per NEC table) to ensure the compressor motor will start on the initial momentary inrush current of 50-60 amps of a typical AC unit. The 20 amp (or 15 amp) AC unit breaker isn't based on the full load running amps.

Another thing to note is that a code-sized breaker for an AC unit doesn't take into account what happens when the voltage goes down which causes an AC unit to draw more current which can cause the 20 amp (or 15 amp) breaker to trip. A compressor load stays relatively constant but as voltage goes down, the motor has to draw more current to try to keep horsepower output up. The motor can end up drawing much more than 80% of the breaker rating and eventually cause it to trip due to the bimetal element heating up more. Low voltage is common in CGs in the summer and is often much higher than the 5% recommended by NEC.

As per NEC you are only allowed to load a breaker to 80% of it's rated capacity that way you have room for start up current. My AC is only on a 15a breaker and draws 10 to 11 amps. A 20a breaker should be more than enough. And as it was stated earlier warm is normal but hot is a problem. However it never hurts to check the connections.

Terryallan wrote:

cavie wrote:
no. a 20 amp breaker on a 12 amp load should not be hot. You have a loose connection or loose breaker on the buss bar.

I don't know. I really don't. But I'm thinkin the AC pulls more than 12 amps.

Starting, yes. Running, probably not generally, or at least not a lot more. 15 kBTU and 12 A works out to an EER of 10.4, which sounds about right. 13 A running would not surprise me. (EER is BTU per watt under some test conditions; SEER is the same, with a specified set of varying test conditions in an attempt to simulate a "cooling season".)

Terryallan wrote:

cavie wrote:
no. a 20 amp breaker on a 12 amp load should not be hot. You have a loose connection or loose breaker on the buss bar.

I don't know. I really don't. But I'm thinkin the AC pulls more than 12 amps.

Our domestic brisk air pulls 14A
Our Coleman Mach 8 plus pulls 13A
(According to our EMS)

Skipg wrote:
The 20 amp breaker for the air conditioner get warm when the air is running. Is this normal?

Warm is normal. A circuit breaker has a bi-metal strip inside which gets warmer as the current going through it gets higher. When the strip warms up enough it "flips" and trips the breaker.

Hot may or may not be okay depending on the actual temp. Breakers are designed to operate at up to 90 degrees celsius max. at rated current under UL standard 489.

Also, UL 489 says: “The maximum temperature on
handles, knobs, and other surfaces subject to user contact during
normal operation shall not exceed 60 °C (140 °F) on metallic and
85 °C (185 °F) on nonmetallic surfaces.”

One thing to note about the panels in RVs is that a 30 amp main breaker and 20 amp AC unit breaker are side by side and you can get a mutual heating effect. The plastic housings in RV panels also are as effective at dissipating heat compared to metal housing in panels in houses & buildings.

I've read of some people aiming a fan at the breakers to keep them from tripping in hot weather when AC units are running constantly. Bad idea IMO.

I'm going to go out on a limb here.

If he is plugged into a older outlet,, with a smallish cord. And,, if he has a lot of other thing drawing load at the same time. It seems to me that then the highest load would cause the breaker to become more warmer.

This is just a guess on my part.

Related story:
While investigating empty spaces in my TT, I found that a hot wire was not even screwed into a 20A breaker. It was just bent in such a way as to make frictional contact. That's a fire waiting to happen even in a stationary home.

Pulled the breaker and found why it was that way. I couldn't get the screw to move so that it would accept the wire. It was frozen in place from the breaker manufacturer. So instead of picking up another breaker, some Forest River worker decided to take the easy way out and put me at risk. I took the breaker to my small town dealer's service manager and even with his tools, he couldn't get it loose either. Would love to meet the guy who installed it ftf.

Keep in mind that thermal breakers do wear out and need replaced (when they trip a lot).

Is it a single or dual breaker? They often use a 30/20 for main/air conditioner, which more than doubles the current carried.