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.
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.