Our trailer is in the driveway, and we are getting ready to have some remodeling work done on our house. We want to use the trailer as a "lifeboat" during construction. We have never done this during the summer (usually we are traveling!), so we will need the air conditioner.My concern is that the garage (where we will be plugging in the trailer) is only on a 20 amp circuit breaker. I don't want to starve the trailer for power and possibly damage the air conditioner.So here is my question -- if we have an electrician come out and install a 30 amp breaker on our panel, will that be adequate to allow us to plug the trailer into the garage outlet and run the air conditioner? (We will be using a very heavy duty extension cord.) Or do we also have to change the wiring and the outlets in the garage?Thank you in advance for your expert commentary!

To add a 30 or 50 amps hookup you will need to add a breaker, appropriately sized wire and receptical.The cost difference between 30 & 50amp should not be that much. If you need one roof air then a 30 amps should be adequate. If you need two roof airs or have other large loads you want to look at going with the 50 amp.

Did that years ago. 30A breaker on panel. Great for working in MH during the summer ~~ OR ~~ when unexpected O/Nite company arrives. Had dedicated 30A Outlet installed outside Garage close to MH.JM2¢ ~~ YMMV

Quick answer is no! Receptacle will not last, wire off existing 20 amp is too small.If you are having electrician come out, have him install a thrity amp breaker, a 120 volt three wire (white, black and bare ground) and a thirty amp NEMA 30TT receptacle.Make sure he knows that it is a 120 volt receptacle.

Thanks for the fast answers!!! I now know what to tell the electrician. Very helpful.

or put a meter on the outlet, considering the ac runs on a 20 amp breaker, you will be close to max, but if u want to manage loads you would prolly be fine.just need to check the voltage when running. anything under 108 is no good.

Newbie-type question about power supply at home

profdant139
Explorer II
Jun 25, 2019
Update (and a question) -- using a heavy duty extension cord and all of the tips above, I tested the voltage in the trailer, which was 119.5. And then I ran the air conditioner, and the voltage is 117.

Not perfect, but it works!!

So of course the follow-up question -- if I run the a/c at 117 volts for a long time, will that harm any of the components in the a/c system? I know that when running the a/c, I will not run any other major appliance (like the furnace or the toaster).

Thanks, as always!
2oldman
Explorer II
Jun 25, 2019
I used a 20a circuit with a 10 awg extension cord successfully.
profdant139
Explorer II
Jun 25, 2019
Thanks!! That totally makes sense -- it is the voltage inside the RV that is indicates whether the RV is getting enough juice.
time2roll
Nomad
Jun 25, 2019
Check the voltage in the RV. Any outlet or right on the breaker... your call.

Just set the meter to AC. There is no polarity for checking voltage.
profdant139
Explorer II
Jun 25, 2019
LittleBill, that is a good observation -- the breaker in the trailer is only 20 amp, and it has never popped.

Now for a really dumb question -- I have a multimeter, but how do I check the voltage of the outlet while the air conditioner is running? It is my amateur understanding that I can just stick the probes into the open slots of the outlet. But does that measure the voltage of the socket that is feeding the air conditioner?

And since I am asking dumb questions, is there a positive or negative slot in the outlet?

Thanks again for your help.
LittleBill
Explorer
Jun 25, 2019
or put a meter on the outlet, considering the ac runs on a 20 amp breaker, you will be close to max, but if u want to manage loads you would prolly be fine.

just need to check the voltage when running. anything under 108 is no good.
profdant139
Explorer II
Jun 25, 2019
Thanks for the fast answers!!! I now know what to tell the electrician. Very helpful.
enblethen
Nomad
Jun 25, 2019
Quick answer is no! Receptacle will not last, wire off existing 20 amp is too small.
If you are having electrician come out, have him install a thrity amp breaker, a 120 volt three wire (white, black and bare ground) and a thirty amp NEMA 30TT receptacle.
Make sure he knows that it is a 120 volt receptacle.
maddog348
Explorer
Jun 25, 2019
Did that years ago. 30A breaker on panel. Great for working in MH during the summer ~~ OR ~~ when unexpected O/Nite company arrives. Had dedicated 30A Outlet installed outside Garage close to MH.

JM2¢ ~~ YMMV
PNW_Steve
Explorer
Jun 25, 2019
To add a 30 or 50 amps hookup you will need to add a breaker, appropriately sized wire and receptical.

The cost difference between 30 & 50amp should not be that much.

If you need one roof air then a 30 amps should be adequate. If you need two roof airs or have other large loads you want to look at going with the 50 amp.

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