running ac

[markdol1]

will running your ac on a 20 amp kill it or do damage to your system? I have a brother in law who will not put the 30 amp breaker in his circuit box of his tt it is 30 amp system from the factory but the previous owner has it on a 20 amp breaker and keeps tripping if his water heater is on electric and microwave trips it when he turns it on.

 

[NH_Bulldog]

Sounds fishy. I have two 15k AC units in my camper and they are on 20A breakers. There should be no issue running the AC.

DO not under any circumstances encourage him to put that AC on a 30A breaker!

The wiring for the AC is 12ga Romex which has a max amperage of 20A. The breaker is protecting the wire from melting. If you add a 30A breaker, that wire will get too hot, melt the insulation and will burn the camper to the ground.

 

[chuckster57]

is the main breaker 20 or 30A?

Which breaker are you asking about? I agree that under no circumstances should you replace a breaker with another rated more amps.

 

[wiredgeorge]

If you have a 30A supply the A/C will be on a 20A breaker. When I turned on my microwave with the A/C running, the main breaker would pop. I eventually ran wiring to an outlet on the back of my camper (all weather 20A) and connect my microwave via a heavy duty power cord to the 20A outlet on a pedestal while the camper is connected to the 30A outlet on the pedestal and avoid popping fuses or having to shut off the A/C while the missus cooks in the microwave. The original power distribution box had dual breakers with the MAIN 30A and microwave 15A on one of the dual breakers.

 

[DutchmenSport]

markdol1, That sounds about right. If plugged into a 20 amp outlet, then all that is available on that circuit is a max of 20 amps and if you go over that, the breaker will pop.

Now, the "statement" is "circuit", not just the individual "plug" in the wall. No doubt the camper is plugged into a normal household outlet with an adapter for the 30 amp camper. When the AC is running and another device is turned on, the 20 amp breaker (in the house breaker box) ... pops.... right?

So remember .... the ENTIRE "circuit" is 20 amps. If anything else is running on that same circuit, then those amps are also added into the total 20. It's MORE than just the camper.

When powering up the AC in the camper, it's probably pulling between 10-15 amps (just guessing here). But, if something inside in the house is also running on the same circuit .... a refrigerator, a fan, maybe the television, and a couple lights .... those items may be 5 amps or more just by themselves. Add the 15 from the AC in the camper and the 5 in the house and now turn on an extra device inside the camper and you've just exceeded the 20 amps and the result is a blown breaker!

So .... what ELSE inside the house is running on that same "circuit." Shut those items off and you'll have better success on 20 amps only for the camper.

 

[JRTJH]

Also keep in mine the distance from the circuit breaker that's tripping and the load at the trailer. If, for instance, you have a 50 foot 12 gauge extension cord plugged into the house and that plugged into the trailer, you have a voltage drop through that extension cord. As voltage goes down, amperage goes up. So, if you're "close to 20 amps at the house (125VAC) with a 10 or 15 volt drop through the lines (from the circuit breaker to the air conditioner in the trailer) you may read 110VAC at the air conditioner connections on the roof. As an example, a 2000 watt load at 125VAC is 16 amps. That same 2000 watt load at 110VAC is 18.1 amps. So your distance from the house circuit breaker and the size/resistance within that cord is also important when you're tripping circuit breakers.

 

[NH_Bulldog]

"I have a brother in law who will not put the 30 amp breaker in his circuit box of his tt"

I think we need some clarity from the OP.

I understood his post to be talking about the camper breaker panel, not the external shore power connection.
I gathered that the 20A breaker feeding the air conditioner and located in the camper power center was tripping. Now, reading it again, it could also be interpreted that he was talking about the main breaker in the camper power center. If that is the case, it seems to imply that someone pulled the 30A main breaker from the power center and replaced it with a 20A breaker, which makes no sense.

Just thinking that if the OP could clarify the exact situation a little better, it may save us from going down this rabbit hole of possible issues with the household power supply feeding the shore power connection, when the question may have nothing to do with that at all.

 

[markdol1]

is the main breaker 20 or 30A?

Which breaker are you asking about? I agree that under no circumstances should you replace a breaker with another rated more amps.

Hi guys , his ac is on a 20 amp breaker .His mains are also a 20 amp breaker His 2016 coachman 32 ft TT is a 30 amp system thats why i questioned him about it .he says when he has his water heater on electric mode it pops a breaker when he turns on the micro. He is not sure of which 20 amp breaker is popping to off.

 

[Rhagfo]

Well most likely he is popping the 20 Main, his panel is rated for a 30 amp main, put in a 30 amp main. The only issue would be is if he is plugged into a 20 amp circuit, then he would likely pop that.
One needs to understand it is difficult to run multiple high draw devices on a 30 amp circuit.
When we spend time at my daughters, Hot Water is on gas only, and we have a 12 volt compressor refer. don't run microwave and AC at the same time.

 

[sourdough]

I think I'm still confused a bit. If the "main" breaker is a 20A in the trailer someone has messed with it - it should be a 30A. The breaker in the house panel should be a 20A - IF the circuit to the receptacle was wired for it (12ga. vs 14ga.). If the smaller gauge wire he should have a 15A breaker in the panel. On a 30A trailer power management is always a top consideration. It's one of the reasons I finally went to a 50A; constantly turning things on and off to keep from popping the 30A breaker in the trailer was more than annoying. Also remember that if the trailer is wired for 30A and has a 30A breaker that the house 20A breaker will pop first if he pulls over 20A vs the RV rated 30A.

 

[markdol1]

I think I'm still confused a bit. If the "main" breaker is a 20A in the trailer someone has messed with it - it should be a 30A. The breaker in the house panel should be a 20A - IF the circuit to the receptacle was wired for it (12ga. vs 14ga.). If the smaller gauge wire he should have a 15A breaker in the panel. On a 30A trailer power management is always a top consideration. It's one of the reasons I finally went to a 50A; constantly turning things on and off to keep from popping the 30A breaker in the trailer was more than annoying. Also remember that if the trailer is wired for 30A and has a 30A breaker that the house 20A breaker will pop first if he pulls over 20A vs the RV rated 30A.

Exactly, you are ALL correct his problem must be its is a shared 20 amp circuit that is popping upon additional loads. I believe the prior owner for some reason switched the main from 30 to 20 amp, I see no other wiring modifications on this system. I think its just a pain in the butt to juggle loads on appliances. I just wondered if a 15,000 btu ac is fine on his 20 amps ,i have to assume it has its own line.

 

[sourdough]

It is very possible a 15k A/C will have issues trying to start on a 20A circuit. I've done it in a pinch at my home on a dedicated 20A circuit before I installed a 50A. It worked but I worried the very few times I did it that I was damaging the A/C. Having the 50A ped/RV outlet installed was less than the cost of a new A/C. I just wouldn't run it if powered by a 20A circuit from the home that was shared inside the house.

 

[markdol1]

It is very possible a 15k A/C will have issues trying to start on a 20A circuit. I've done it in a pinch at my home on a dedicated 20A circuit before I installed a 50A. It worked but I worried the very few times I did it that I was damaging the A/C. Having the 50A ped/RV outlet installed was less than the cost of a new A/C. I just wouldn't run it if powered by a 20A circuit from the home that was shared inside the house.

So you shared my concern about the ac being damaged. I am going to talk to the previous owner about why he changed the main to a 20-amp breaker. I installed a 30-amp line in my garage so when i bring my TT home to work on i can plug in to run things. I am installing a Coleman soft start so i can safely run my Mach q ac with a lower load. Thanks for all your help as usual, I think we beat this to death.

 

[KevKt]

It is very possible a 15k A/C will have issues trying to start on a 20A circuit. I've done it in a pinch at my home on a dedicated 20A circuit before I installed a 50A. It worked but I worried the very few times I did it that I was damaging the A/C. Having the 50A ped/RV outlet installed was less than the cost of a new A/C. I just wouldn't run it if powered by a 20A circuit from the home that was shared inside the house.

I suggest adding a soft start to the a/c unit, it will reduce the surge on startup possibly preventing the breaker from tripping and also easier on the a/c unit.

 

[sourdough]

I suggest adding a soft start to the a/c unit, it will reduce the surge on startup possibly preventing the breaker from tripping and also easier on the a/c unit.

A soft start can be beneficial but my concern was that it sounded like the RV was being powered by a 20A circuit shared within the house along with the RV. In that case, and depending on what was on at the time in the house, a soft start (if it would work) would still mask a potential low voltage/amperage condition that could harm the A/C. It was pointed out the home has a dedicated 30A circuit for the RV.

 

[jxnbbl]

If (not sure it is) talking about using 20A circuit for shore power, regardless of how good the source is I would use my EMS at the end of the extension cord to detect low voltage.

 

[rlh1957]

will running your ac on a 20 amp kill it or do damage to your system? I have a brother in law who will not put the 30 amp breaker in his circuit box of his tt it is 30 amp system from the factory but the previous owner has it on a 20 amp breaker and keeps tripping if his water heater is on electric and microwave trips it when he turns it on.

AC year & type will determine how much power an AC requires.
If camper is on a house 110V 20 Amp circuit (must not be an GFCI circuit)… some AC’s won’t run without kicking circuit. Newer AC’s can run fine on a 20A or some even will run on 15A
Now as far as running much else on a 20A shore line with an AC going… not so much.
HW electric will pull 1500W - 1800W which usually overloads a 20A breaker that already has 1400 -1800W already running.

It does not hurt your system… the incoming power breaker trips on overload.

 

[Gypsyrose-KEY]

will running your ac on a 20 amp kill it or do damage to your system? I have a brother in law who will not put the 30 amp breaker in his circuit box of his tt it is 30 amp system from the factory but the previous owner has it on a 20 amp breaker and keeps tripping if his water heater is on electric and microwave trips it when he turns it on.

If all you are running no problem, add other electrical items and yes you are taking a risk