we have a toyhauler and the garage has 2 air vents but is still hotter back there. this will be daughters room.We have 2 AC units. master and center ac. but we have a fantastic fan in the garage. It is not pre-wired to accept an ac unit BUT can I still have one put in it? have the service guys run the necessary wires and get a 3rd ac back there?I was searching the net for info but haven't found anything helpful to me and knew someone here would have an answer.thanks for any help.

I have a Voltage 3895, and ordered it with 3 A/C's and only got 2.... Camping world in Houston installed the third unit with a seperate 30amp cord.... works awesome, even though it's not on the load management system... It gives me more options with the 50amp load management to run more! I haven't come accross any campsites that only have 50amp service with out having the 30amp right beside it, so it hasn't been an issue. Mine wasn't pre-wired for 110, it had 12volt with a fantastic fan installed, they ran 110 and put in a junction for the power cord outside.

If you can get the wiring back there, have a spot on your panel and have a big enough service like 50 amp. I don't see why not.

Thank you very much. I now know there is hope to get one installed. Now I can call the service dept. and know what I am asking for and I will make it happen.appreciate the info. it helped alot!!

I called and they can install a separate breaker and I will plug directly into 30 amp. I am thrilled :) now getting that 3rd ac. Thanks again!

I don't usually post here much but I do a lot of reading and we had just decided to do this to our Raptor this past weekend. Thanks for the timely info guys. Here's a question though, would it be possible to run just the 3rd ac of a 15amp connection if you were to use a 30amp to 15amp adapter? The reason I ask is that we were in a 30amp spot this past weekend so we could only use one unit at a time but was thinking I could have run the garage unit seperately on the 15amp breaker since that would be the only thing on it.

AC without pre-wire? | Good Sam Community

23 Replies

FunnyCamper
Explorer II
Sep 17, 2013
yes I agree.

also I know that some good placed fans can help get some air back there so no one suffers too much :)
CA_Traveler
Explorer III
Sep 17, 2013
FunnyCamper wrote:
wow. good electrical info for me.

our state parks are mostly 30 amp pedestal with a 15 amp plug included on the stand. I was hoping to plug into the 30 amp and run just one of my main ac and then the separate garage I would run into the 15 amp plug. that is when the service guy said don't do that :) only a 20 amp plug will be good enough for that 13.5 ac in the garage.

I will check each of my state parks I love and ask exactly what power is on that pedestal. I know the 30 amp plug is there, but will ask what the amps are on the smaller plug. hopefully 20 amp would be sweet to hear is included.
In all cases a DVM is your friend as you want good voltage for ACs and especially when you use both plugs on the pedestal. I'm always suspicious that a 30/20 pedestal is wired for 30A and not a 50A draw.

Don't be surprised if the park doesn't know what the plug is or gives you the wrong answer. The term 15A or 20A is often used to mean the same thing.

BTW If you're at a nice beach site and it's hot have DD come in the front which solves the problem.
FunnyCamper
Explorer II
Sep 17, 2013
wow. good electrical info for me.

our state parks are mostly 30 amp pedestal with a 15 amp plug included on the stand. I was hoping to plug into the 30 amp and run just one of my main ac and then the separate garage I would run into the 15 amp plug. that is when the service guy said don't do that :) only a 20 amp plug will be good enough for that 13.5 ac in the garage.

I will check each of my state parks I love and ask exactly what power is on that pedestal. I know the 30 amp plug is there, but will ask what the amps are on the smaller plug. hopefully 20 amp would be sweet to hear is included.
CA_Traveler
Explorer III
Sep 16, 2013
SpencerRB wrote:
Maybe I'm mistaken regarding the load management feature on the triple A/C trailers. Maybe it is only used when attempting to run multiple A/C's off the genny, but if my memory serves me correctly, I've read some people having issues running all 3 at the same time when plugged into 50 amp service.
3 ACs will not trip the CB on 50A unless they are wired on the same leg which would not be the best balance of loads.

2 ACs on one leg combined with other loads could draw more than 50A and trip the CB. Like 2 ACs, HW, hair dryer, MW or whatever.
allcool
Explorer
Sep 16, 2013
Sorry, my confusion, didn't realize the subject was a campground 50 amp service.
CA_Traveler
Explorer III
Sep 16, 2013
allcool wrote:
SpencerRB wrote:

I believe he has 50 amp on the trailer. He was adding a 20 or 30amp separate circuit for the 3rd A/C separate from the trailer electrical.

You do bring up an interesting point. From my understanding, 50amp service is actually rated at 240v, so at 120v, it is rated at 100amps. If this is the case, why do 50amp trailers need load management devices to handle 45 amps (3 15k) of A/C units? This should be less than half of total capacity.

Not exactly...
Its 25amps at 240v and 50amp at 120v.
100amps at 120v would be 12,000 watts, not happening on a Onan5500, ever.

If you measure between both legs of 120v it will be 240v on the 5500 genny. Either 240v leg measured to neutral or ground, gives 120v.
Thats why there are 2, 30 amp breakers, one for each 120v leg of the 240 being produced by the genset. Each leg is good for a little less than 25amps @120v, more or less. So thats how it gets a rating of 50amps, 2 separate 25amp 120v circuits. Actual specs, its 45.8 amps, so in reality, each 120v leg is rated for 22.9amps constant draw...

Make no mistake, 5500 watts is 5500 watts, no matter what voltage. 5500w, thats all we get out of the Onan 5500. Although a surge to 6000watts momentarily will happen.

Let's clear up the confusion: A 50A RV circuit is 240/120V 50A and the 50A rating applies to 240V. This 4 wire circuit can supply 240V @50A or 120V @ 50A on each hot leg or any combination of 240V and 120V as long as the current on each hot legs does not exceed 50A. Few RVs use 240V so we tend to think of it as 2 circuits of 50A each. And the CB is a dual 50A CB. So 50x240=2*50*120=12K Watts available on this circuit.

Don't know how we got into gens but generally you don't get 240/120V from an Onan under 10K watts. Instead they are 2 120V circuits.
SpencerRB
Explorer
Sep 16, 2013
allcool wrote:
SpencerRB wrote:

I believe he has 50 amp on the trailer. He was adding a 20 or 30amp separate circuit for the 3rd A/C separate from the trailer electrical.

You do bring up an interesting point. From my understanding, 50amp service is actually rated at 240v, so at 120v, it is rated at 100amps. If this is the case, why do 50amp trailers need load management devices to handle 45 amps (3 15k) of A/C units? This should be less than half of total capacity.

Not exactly...
Its 25amps at 240v and 50amp at 120v.
100amps at 120v would be 12,000 watts, not happening on a Onan5500, ever.

If you measure between both legs of 120v it will be 240v on the 5500 genny. Either 240v leg measured to neutral or ground, gives 120v.
Thats why there are 2, 30 amp breakers, one for each 120v leg of the 240 being produced by the genset. Each leg is good for a little less than 25amps @120v, more or less. So thats how it gets a rating of 50amps, 2 separate 25amp 120v circuits. Actual specs, its 45.8 amps...

Make no mistake, 5500 watts is 5500 watts, no matter what voltage. 5500w, thats all we get out of the Onan 5500. Although a surge to 6000watts momentarily will happen.

I'm aware that an Onan 5500 produces 5500 watts, but no one mentioned a generator.

I'm referring to your standard 4 wire 50 amp 'plug in' service. http://www.myrv.us/electric/Pg/50amp_Service.htm

Maybe I'm mistaken regarding the load management feature on the triple A/C trailers. Maybe it is only used when attempting to run multiple A/C's off the genny, but if my memory serves me correctly, I've read some people having issues running all 3 at the same time when plugged into 50 amp service.
allcool
Explorer
Sep 16, 2013
SpencerRB wrote:

I believe he has 50 amp on the trailer. He was adding a 20 or 30amp separate circuit for the 3rd A/C separate from the trailer electrical.

You do bring up an interesting point. From my understanding, 50amp service is actually rated at 240v, so at 120v, it is rated at 100amps. If this is the case, why do 50amp trailers need load management devices to handle 45 amps (3 15k) of A/C units? This should be less than half of total capacity.

Not exactly...
Its 25amps at 240v and 50amp at 120v.
100amps at 120v would be 12,000 watts, not happening on a Onan5500, ever.

If you measure between both legs of 120v it will be 240v on the 5500 genny. Either 240v leg measured to neutral or ground, gives 120v.
Thats why there are 2, 30 amp breakers, one for each 120v leg of the 240 being produced by the genset. Each leg is good for a little less than 25amps @120v, more or less. So thats how it gets a rating of 50amps, 2 separate 25amp 120v circuits. Actual specs, its 45.8 amps, so in reality, each 120v leg is rated for 22.9amps constant draw...

Make no mistake, 5500 watts is 5500 watts, no matter what voltage. 5500w, thats all we get out of the Onan 5500. Although a surge to 6000watts momentarily will happen.
CA_Traveler
Explorer III
Sep 16, 2013
OP One technique is to route the 3rd AC wiring to a male and female plug in a storage compartment and then continue on to the 20A RV panel CB. Now use a heavy construction cord (10 ga) to connect the AC to a 20A pedestal plug when 50A is not available. This is a common technique and there are posts on this mostly for a 30A rig with 2 ACs.

However a 30A and 20A pedestal may/may not be wired to handle a 50A load. You should be monitoring to monitoring the voltage to be sure a pedestal is OK. Another pedestal in the same CG that is closer to the CG could also be helpful.

I added a second circuit for ceramic heaters when we're on a 30A pedestal. By default it's plugged into a dedicated 20A RV circuit. But when cold it gets plugged into an available 20A plug.

The dealer is right about a 15A plug. However many pedestals have a dedicated 20A plug.

Lots of fun. :B
CA_Traveler
Explorer III
Sep 16, 2013
SpencerRB wrote:
I believe he has 50 amp on the trailer. He was adding a 20 or 30amp separate circuit for the 3rd A/C separate from the trailer electrical. Thanks

You do bring up an interesting point. From my understanding, 50amp service is actually rated at 240v, so at 120v, it is rated at 100amps. If this is the case, why do 50amp trailers need load management devices to handle 45 amps (3 15k) of A/C units? This should be less than half of total capacity.It's a 240/120V circuit and since few RVs have 240V appliances most think of it as 2 50A circuits. That's a lot of power and will run everything including 3 ACs. For this load management is not needed.

But load management does play a part for 20A and 30A pedestals and the gen.

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AC without pre-wire?

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