wiring a new 30 amp outlet

[gparker]

I want to put a 30 amp outlet near where I park the trailer so I can run A/C. Etc. We had an electrician run underground lines out to the general area several years ago for Christmas lights, etc. Pretty sure it is 20 amps with 10 or maybe 8 wire. It is a long run from the breaker box. The current outlet has its own breaker too. Can I just change the breaker to a 30 amp? If I can and do, can I safely operate Christmas lights from a 30 amp outlet? Or, should I tap off the line at the distant outlet after changing the 20 amp to a 30 amp at the breaker box and put in a new breaker box with a 20 amp for the lights next to the old?
Thanks, Greg

[jimmickle]

First thing is to check the size of the wire. The minimum for 30 amp is 10 gage, and if the run is over 50 feet or so, you should probably have 8 gage to prevent a major voltage drop. You should be able to run your A/C on a deadicated 20 amp circuit. I did it at my previous home and at my new home. I would try it with the 20 amp circuit before spending a lot of money and time changing breakers, outlets, etc.

If you decide to change to 30 amp, it would be a good idea to add a 20 amp breaker and ground fault outlet for the lights. I assume that the current outlet is ground fault protected as required by code.

[gparker]

Thanks for the reply. The current setup is with a GFI and has a green and a white wire. I looked in the breaker box and the circuit goes through a 50 amp breaker, which I assume is only hooked up on one side. I can't imagine the electrician wiring for Christmas lights on a 50 amp circuit.
I just got the trailer, which sat for about 18 years. When I turn on the A/C while plugged into the present circuit, the a/c will struggle to come on, then run for 15 minutes or so, then quit. I am assuming it is not getting enough ampereage and is therefore not running well. I know the newer units will run on 20 amps, but this thing is 30+ years old. At any rate, even if I replace it, aren't you supposed to use a 30 amp outlet for running big draw items such as A/C?

[dwightdi]

From the unit's reaction you are likely to have an excessive voltage drop due to inadequete wires along the way. You should attach a voltmeter at the circuit breaker box in the trailer and then have someone else turn on the air conditioner while you watch. If the voltage dips below 100 volts you need to run a new dedicated line or 8 gauge wires to the trailer from your main box in the house. Just to be sure you are not losing too much at the house box, install the voltmeter at the main box in the house and repeat the experiment.
It could be your house is at the end of the line or has a problem with the electric company's transformer feeding the house.

[fastrob]

Originally Posted by gparker

I just got the trailer, which sat for about 18 years. When I turn on the A/C while plugged into the present circuit, the a/c will struggle to come on, then run for 15 minutes or so, then quit. I am assuming it is not getting enough ampereage and is therefore not running well. I know the newer units will run on 20 amps, but this thing is 30+ years old. :

Congratulations on getting an Airstream.
Could the problem be with the a/c unit?
After making sure the voltage is ok maybe the problem lies in the a/c.
Lots can go wrong with an old a/c.
I have the same problem with mine but it worked fine a few years ago.

R

[john hd]

if you want to limit the voltage drop to 3% use this handy calculator to figure out your wire size.

http://www.elec-toolbox.com/calculators/voltdrop.htm

john

[gparker]

Thanks for the welcome, Fastrob,
Yes, it could very well be the A/C unit, but short of hauling the trailer to the nearest campground and plugging in on their circuit, I can't be sure unless I make sure it is getting enough juice from the house line. Good point about the voltage drop-- I will check it out and get back to you guys.

[uwe]

The A/C in my 1971 Tradewind ( Armstrong) would not run on a 20A circuit with the RV to household adapter. It would run great at the campgrounds 30A plug-in.
Be careful, the older A/C systems can take seriuos damage from being run at low amp/voltage conditions.

[crowbar68]

all good advice. you definetly need to know your wire size before swapping breakers. that calculater johnhd has will help you figure what you need. i run my ac on a 20amp single pole. ironically my 20a breaker just went bad and had to replace. it runs fine on the 20 amp. i try not to run alot of stuff on it either. mainly the ac and a few lights w/ univolt to keep battery charged. i would prefer a 30 ampbut would have to run a new line to do so.

crowbar

[gparker]

I went out this afternoon and realized that the PO had a voltmeter installed near the AC. So, I turned on the unit and watched the voltage drop from 110-115 to about 65!!! I promptly shut the AC off. I guess the run is too long from the breaker box for the wire size. It would be a royal pain to have larger wire run. i'm wondering if the power company would drop a line down from the light pole which is only about 15 feet from where I park? If I pay for a meter, I don't see a problem--am I right?
Greg

[crowbar68]

run a new line you'll be better off. #6 wire w/ a sub panel. for the money you will spend, i usuually recomend a 60a to 100a sub panel to tap off of to run that hot tub/xmas lts/pool/lts/rv/ youknow.
the little extra money you spend vs. what you might do is negligible. go for the power.

crowbar

[empresley]

"I went out this afternoon and realized that the PO had a voltmeter installed near the AC."

Greg, If the information is on the face (so that you don't have to remove), could you share what type voltmeter is installed? Is it a digital readout? I would really like to monitor voltage under load since we have numerous locations we hook-up to 30A circuits. (Home, Office, Family Farm, AS parks, State Parks, etc.)
Thanks,
mp.

[fastrob]

Originally Posted by gparker

....It would be a royal pain to have larger wire run. i'm wondering if the power company would drop a line down from the light pole which is only about 15 feet from where I park? If I pay for a meter, I don't see a problem--am I right?
Greg

We had 5 poles put in on our property to get power to the house. We paid a contractor to put them in. The power company "owns" them when electrified. We have our meter on the pole. We were told by the power company that if anyone else draws power off our line we could not use the pole for our meter, the meter would be required to be attached to our home. I suggest you check with the local power company before hiring an electrician.

R

[ALANSD]

[quote=empresley]"I went out this afternoon and realized that the PO had a voltmeter installed near the AC."

You can get a plug in volt monitor meter at most Rv supply places.

[gparker]

This voltmeter is the old, cool analog kind with a needle that moves from left to right as voltage goes up. Made by Simpson, about 2 inches across. Bet you could get one on ebay. Of course the new ones are nice-- digital etc and just plug into an outlet like one of those air fresheners.

I guess I will pull some #8 wire through the conduit. Not looking foreward to that.
Greg

[bake315]

Originally Posted by gparker

I guess I will pull some #8 wire through the conduit. Not looking foreward to that.
Greg

Count your blessings.... I get to pull #6 wire through mine.

[gparker]

The voltmeter I have is an old analog model like you used to see in old movies. Pretty cool. Made by Simpson. Probably find on ebay. Newer ones plug into an outlet like an air freshener.

[crowbar68]

Originally Posted by coriolis1

Count your blessings.... I get to pull #6 wire through mine.

don't forget to use "soap" on those wire pulls. it will make it much easier. especially if it's long.


crowbar

[bake315]

Originally Posted by crowbar68

don't forget to use "soap" on those wire pulls. it will make it much easier. especially if it's long.


crowbar

Yep, I'm acquainted with that lovely yellow slime!

[john hd]

pull a small rag through the duct with the soap on it first. it will spread it throughout the entire length. then refish and pull your wire.

liberal amounts make it much easier, we use 5 gallon pails of the stuff for long pulls in 6 inch duct!

john