120 VOLT INPUT

Your air conditioner probably draws around 12-13 amps. There is no reason a 20 amp circuit won't allow it to operate. Every RV I have had was able to run the air on a 15 or 20 amp circuit.

Did you try the air with all RV breakers off except the main and air?
Otherwise NO. NEC does not allow parallel conductors to increase amps.

AATIM wrote:
Brand new to RV'ing (Winnebago 32' motor home). Slowly figuring things out, including that 20 amp/120 volt from my house will not power my air conditioner. RV isn't stored long term at our house (space/city ordnance) so don't want to install a 30 amp line. Does anyone know if there is a "reverse splitter" where I can take two 15/20 amp cords from separate house breakers to one 30 amp cord and then to the RV's power cable?

That question keeps coming up :) The answer is essentially NO. The likely issue is the 15a will run the a/c but you have other loads on as well, including anything in the stick house on that same circuit. Or the extension cord is way too long as suggested above, or both.

Careful, if you hook up to 2 outlets on separate legs of your house 240v wiring, you will wind up with 240v to the RV and will fry everything.

I'm thinking you went cheap with your 20AMP hookup. I have two trailers here connected to my garage 24/7 on two separate 120VAC 15A/20A circuits. I run my 13,500BTU air conditioner just fine in both trailers. I do of course have to make sure no additional high wattage appliance is turned on otherwise it will trip the house breaker.

This is my house/garage setup for running my two 30AMP trailers.
Let me list what I do here and maybe it will trigger what you may want to do on your end connecting up to the house/garage.

I run two 120VAC drop cords from my garage to power up my 30Amp fifth wheel and 30Amp OFF-ROAD POPUP trailer when parked here at the house.

One receptacle in the garage is a stand alone receptacle that was installed to run an air compressor at one time and this is the only thing on its circuit. I use this to feed my fifth wheel. My OFF-ROAD POPUP uses a 120VAC receptacle that located near the garage door and is on a different circuit breaker then the one I am using for the fifth wheel trailer.

Before hooking up to the Garage 120VAC receptacle I would use a circuit tester from LOWES -WALMART that looks like this

Do not use the garage 120VAC receptacle if it does not check out "CORRECT" by the correct position of the tester lights...

What I do is use two 10-GAUGE (10-3) HD Contractor type 50-foot that run out towards both trailers. I have used a 12-gauge (12-3) long extension cord with out any issues but would never use the 14-16 gauge "RED ORANGE" smaller size extension cords you find at LOWES-WALMART. They are just too small to handle the trailers.


Out in the middle of the yard I use a RV30A-15A DOGBONE STYLE long adapter plugged into the 50-foot extension cords. These come from WALMART and look similar to this...


I could never use the small round black type RV30A-15A adapters as they always tend to get hot me when used just a short time...


What you don't want to happen is for the adapters to heat up your shore power cable which might end up looking like this and will need to be replaced.


Now all I do is plug the 30AMP trailer SHORE POWER CABLE into this RV30A-15A long adapter laying in the middle of the yard.

To insure the 120VAC power source is safe to use I will use one of these RV PLUG IN 120VAC AC voltmeters (AMAZON) plugged into a receptacle inside the trailer that is in a good view spot so you can glance at it when you need to. This will check the 120VAC level coming from the house. The part I like about this meter is it has a safe zone "GREEN" printed on the face and if the AC voltage is within this safe limit then is ok to use the power - even for one roof mounted air conditioner unit.


I will turn a few thing on inside the trailer for 10-minutes or so and then back outside and check all of the connection points to see they are not getting warm to touch. This includes the garage 120VAC receptacle.

This is pretty much what we do here for our two trailer that is hooked up to the 15AMP service from the garage.

We can run just about everything inside the trailer we want to run but have to watch sometimes what is on at the same time. i.e. we can never run the air conditioner and the high wattage microwave at the same time otherwise it will trip the breaker in the garage.

We sleep in both the trailers all the time when sitting in camp back yard and of course this is where I get to do all my mods and fix up things for the every changing OFF-ROAD POPUP configurations for my emergency radio operations I am connected with. Its a great get away just sleeping over in the back yard sometimes. Wifes gets to use the fridge to supplement her kitchen fridge. Good spot for my beers too...

ALot of folks will warn you about about all kinds things that might happen when only connected to a 15/20AMP service but if you follow some good guidelines like I have listed here you should be ok. Has worked good for me over the past few years.

We use the extension cord and RV30A-15A long adapter when on the road alot. You never know when we may need some power sometimes. Works great when visiting family - I just hookup outside their house and we sleep in the trailer.

Hope this helps

food for thoughts
Roy Ken

AATIM wrote:
20 amp/120 volt from my house will not power my air conditioner.

Are you using an extension cord?

This is sort of what you want. You can use 30/15 adpaters on each of the inputs. Would I use it? No.
ADT-230

Get the fire department on the way when you plug it in. 30 amp has 1 positive, 1 neutral and a ground. a 50 amp has 2 positive. I don't think any electrical code would recomend it.