Run Both Air Conditioners with 30-amp service

[Son_of_Norway]

This is a project for those of you camping in hot weather in an older motorhome with 2 air conditioners but only 30 amp service. As you know, you can only run one AC at a time while on pedestal power. I have posted and puzzled about this and this is the easiest and cheapest way that I could come up with to deal with the problem. It is to install a switch in the generator compartment to choose between generator power and pedestal power.

It takes a 3 position, 4 row, 16 connector AC rotary cam switch. (Amazon) Also a 3" extra deep box, an extra deep box extension, weatherproof cover, some 10 gauge wire, a length of 10 gauge extension cord, a three prong plug and a thirty-amp plug.

The job is pretty straightforward. Determine which wire is which. Label then disconnect the wires, Take out the old box. Install the new one. Run the wires and cords in. Wire the switch, wire the plugs. Close up the box and make it pretty.

This is a view of the wiring and the switch:



This is a view with the two cords:



I will hang the cords on a hook at the side. The switch requires jumpers on the house side. Be sure and test the logic of the switch for yourself before wiring.

It is nice to finally have a cool RV. I have a window AC that I used to use but now I can put it on Craigslist.

[time2roll]

Same circuit can be created with a small automatic transfer switch if preferred.

[MrWizard]

this should really be clarified
its (2) A/Cs
one on the RV 30a, one on the Pedestal 20amp ciruit

it is a 30amp RV

it is NOT (2) on the 30amp breaker

[RLS7201]

Dutch_12078 wrote:
I would like to give appropriate credit for the picture below, but I do not remember who originated it. My thanks to them anyway!


Click For Full-Size Image.

Dutch, That's a picture of the 7K Onan on my 95 Bounder.
In the original article, I included a wiring print. It was originally posted on the Yahoo/Bounder Forum. A copy still resides in the files section, under a different persons handle.
2 A/Cs on 30 amp coach


Richard

[2oldman]

Dutch_1207 wrote:

It works quite well because only one A/C runs on the 30 amp outlet, with the other one running independently on the 20 amp outlet.

Not real clear in the OP. Or the post title.

[Dutch_12078]

ScottG wrote:
Any time I've run just one AC on 30A my plug/ receptacle has gotten at least warm (even with new trailer). I have to wonder how often this would actually work.

It works quite well because only one A/C runs on the 30 amp outlet, with the other one running independently on the 20 amp outlet.

[Dutch_12078]

I would like to give appropriate credit for the picture below, but I do not remember who originated it. My thanks to them anyway!


Click For Full-Size Image.

[ScottG]

Any time I've run just one AC on 30A my plug/ receptacle has gotten at least warm (even with new trailer). I have to wonder how often this would actually work.

[MrWizard]

elegant solution some people use male and female 20amp sockets and plugs to break the circuit and run the extension cord to the pedestal or connect it to the generator

this ties in with a generator power discussion in another thread
the second A/C on the 20amp HACR breaker on the genset
is totally isolated from the 30a main service for the house
that 20amp circuit does not 'aid/help' the house side, even when the second A/C is not being run, there is NO power cross connection between the circuits

[Son_of_Norway]

Right, the 20 amp generator circuit only powers the 2nd Ac. For this set-up you run 2 cords to the pedestal. One 30 amp and one 20 amp. The circuits are kept separate up to the pedestal.

[time2roll]

Do I assume your RV was wired to where the second A/C only ran from the secondary generator circuit? The switch must just tie this circuit into the main 30 amp cord.

Or are you running a second cord out to the 20 amp GFI circuit?

[Mandalay_Parr]

I run both on 30 amps but not too much else.

[2oldman]

Ok. I guess you're good unless your wiring heats up.

[Son_of_Norway]

This is to run both AC and whatever else while on shore power, or use generator power for the AC's and whatever else as usual. The switch only allows you to use one type of power at a time.

[2oldman]

You mean you run both airs on generator, or one on shore and one on generator?