Monday, November 28, 2022


RV Mods: 50-amp service at your home base

By Jim Twamley

Parking your RV at a friend’s or relative’s house? What happens if you keep blowing fuses because your RV pulls more amps than the 15-amp circuit can supply? Heatwave not allowing you to use your air conditioner because you really need 50 amps to make it happen? Well, do not despair, help is as near as your local hardware store.

Depending on the electric code of the state you live in, this job may be done several ways, either as a temporary setup or as a permanent outdoor 50-amp receptacle. Either way I highly recommend you hire a certified electrician to connect it for you because we are dealing with electricity here and it’s DANGEROUS if you don’t know what you’re doing. In reality, it’s dangerous even if you do know what you’re doing! A certified electrician will install your receptacle using the proper code guidelines for your state. That being said, your electrician can put a 50-amp circuit breaker in the electric service box, hook up #6 wire to it and run it outside and into a weatherproof 2 gang (deep) box with a weatherproof cover and you are in business.

In my case I could not route the Romex #6 wire casing outside without tearing out the drywall around the box. Since we were only staying here a few days, my brother-in-law and I decided to rig a temporary “emergency” setup until a more permanent solution could be achieved. I bought about 10 feet of #6 Romex wire which has four wires in a sheath. It consists of a ground wire, a white #6 common, a red #6 and a black #6 and costs around $2.50 per foot at Home Depot. I also purchased a 50-amp breaker that fit the electric service box and a 50-amp female receptacle that has its own self-contained box. We basically made a heavy-duty extension cord that comes right off the electrical service box.

scottbb on

Your electrician will remove the service cover and determine if there is room for a 50-amp breaker. In our case we removed a 40-amp breaker that wasn’t being used. We installed the receptacle after stripping the proper amount of wire off the Romex. We removed about 16 inches of the Romex cover to expose the wires that would be going to the breaker and service box. We stripped the tips of the wires and inserted the black into one side of the breaker and the red into the other side. It doesn’t matter which side your electrician puts the red or black wires on.

Next we inserted the white common wire on the electric service common bar and also inserted the ground wire onto the ground bar in the box. All these connections are made secure by tightening screws down on the wires. How your electrician brings the wire out of the box to the receptacle depends on the local electric code. We inserted the breaker, tested the receptacle with a volt meter, plugged in the RV and flipped the breaker to the “on” position and have been enjoying refreshing air conditioning ever since.

The way you test to make sure the receptacle is properly wired is to set your volt meter on AC to measure 240 volts. Place one lead into the receptacle where the black wire is and one where the red wire is and you should get a reading of 240 volts. Move the black test lead down to the common (white) wire and you should read 120. Now move the test lead that is on the red wire over to the black side while leaving the other test lead in the common (white) and you should read 120. Next move the lead on the black wire to the ground wire (the hole) and the other lead remains in the common (white – bottom blade) and you should read 0. If it checks out, you’re good to go; if not, then troubleshoot the problem. Make sure the ground wire is in the green receptacle screw down holder and the common (white) is in the bottom blade position on the receptacle.

Here is a great link where you can learn more about how a 50 amp RV service is wired.

Warning: Do not attempt this as a do-it-yourself project; use a qualified electrician to install it for you. This information is only intended to inform you so you can speak intelligently to the electrician you hire to install your outlet.




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Al & Sharon
5 years ago

Good suggestion, but it sure is lacking in very important necessary details. Such as, RV 50amp service is really 100amps. 50amps on each hot leg. You don’t mention anything about installing a double CB, with 50amps for each leg.
These details are very necessary, as some or many certified home electricians are not knowledgeable about wiring service for RV’s.

Yes, you supply a link to information about how RV 50amp service is wired. HOWEVER you do that as in kind of nice to read, when it should be, “BEFORE you do the modifications or hire an electrician to do the work, read this link about how RV 50amp service is wired, and be sure the electrician is knowledgeable of how RV service is wired.

Jay French
5 years ago

Kickstart is a hard start device on the market since 1989. At first glance, Kickstart hard start devices appear to be no different than the multitude of two-wire start-assists that have been on the market since the early 80’s. But a closer look reveals a high-quality potential relay “combined” with a high-quality start capacitor. It is this “true” potential relay that distinguishes the Kickstart brand of hard start devices from other starting devices that still use timers, PTCR devices, or circuit boards. It is the unique patented design that allows a single potential relay to replace the multiple potential relay inventories without sacrificing quality. This “Mod” allows me to plug into a 20 amp circuit or use a 20 amp 3000 generator to run my entire 50 amp rated unit, but remembering to turn off the air conditioner for the microwave, coffee pot or hair dryer.
The reason they are potential relay is because they operate on potential voltage.
Course, this is just an opinion from 30+ years in the commercial refrigeration trade (far better than an AC man) best friend of mine who ordered & installed mine for a few cold beers & a barbecued steak.

5 years ago

A lot of people make adapters to use existing “heavy amperage” wiring, like that for buzzbox welders or home dryers. No messing around in the breaker box if that makes you nervous, but you DO still have to know what you’re doing (making your own or checking out someone else’s adapter). Dangerous situations can be invisibly created by the wrong wiring in the adapter.

Jim is totally correct here that you shouldn’t attempt DIY wiring unless you (correctly) are confident you can (correctly!) do it. That said, I wired my own 30A power at home. If you’re interested in how I did that (including a wattmeter on the outlet), check it out here:

Jim is also correct that, even if you ARE confident your power pole was wired correctly, you should still test it… here’s a video I did on testing that:

Hope it’s useful… 🙂


Tom Lang
5 years ago

I would bet $10 that you could have easily used the existing unused 40 amp breaker that is already in the panel withour ever tripping it!

Dr4Film ----- Richard
5 years ago
Reply to  Tom Lang

You are absolutely correct! I do that when staying at my brothers place in Dansville NY hooked to the power at his barn. I made an adapter that plugs into his three wire 220 VAC welder plug and then use a separate wire for the missing neutral. However the neutral and ground are bonded at the main barn panel anyway.

Mike Sokol(@mike)
5 years ago

That’s a code violation and shouldn’t be attempted. Even though a 3-wire 240-volt outlet was allowed by code for dryer outlets in the 70’s and 80’s (I believe), it was never intended to run unbalanced 120/120-volt loads like you’ll find in an RV. There’s a lot of good reasons for not doing this, but know that if you do make an adapter like this and something goes wrong, his house insurance may be voided and extra liability issues kick in.

Mike Sokol(@mike)
5 years ago
Reply to  Tom Lang

It’s completely code compliant to use a 40 or 30 amp circuit breaker to feed a 50-amp receptacle. But it needs to use a double-pole breaker and best practice suggests that you mark the receptacle as 30 or 40 amps or whatever the circuit breaker is. You do get a lot more wattage from any 50-amp receptacle compared to a TT-30 receptacle simply because it’s really 50+50, 40+40, or 30+30 amps.

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