Wire for 50A 220V Service - 110' run

smkettner wrote:
Why not pull 120/240v service off the existing circuit?
At least double the power and much less effort.

Why not give him a can of gas and some matches?

The existing service is a 30A/120v circuit. 30A requires #10, but they used #8 when installed because of the distance.

If you are suggesting that he split that hot leg into 2 to create 30A/220v, he will overload that neutral and cause a fire.

A 50A RV plug uses a 240v feed from the panel but splits it into two 120v circuits at the RV. You need FOUR conductors: 2 hot legs at 120v each, a neutral and a ground.

Hence the 3-conductor alum wire the OP has will not in any case.

tvman44 wrote:
I guess you could, but I would not use aluminum wire at all. #6 aluminum wire is too small I think for 50 amps.:E

Second. #6 copper might be enough but for a 100 foot run, If you are going to be getting close to 50 amps, consider #4,, let me look up some numbers. 36 Copper has about .04 Ohms per 100 foot. (.08 when you run it back) so at 50 amps that's 4 volt drop in the loop.

#6 Aluminum is .. Far Lossier.. (Frankly I did not find a chart for Aluminum wire) plus you need special connectors on each end to make sure it does not get much worse very fase.. I'd not use Aluminum wire.

Why not pull 120/240v service off the existing circuit?
At least double the power and much less effort.

The short piece consists of three wires. Two are #2, the other is #4. This is what it says on the wire:
2 AWG AL USE-2 600 VOLTS
and
4 AWG AL USE-2 600 volts.

The long piece is also three wires:

6 AWG AL USE-2 600 VOLTS

Currently, there is a four-wire shielded 8 AWG buried cable running from the breaker box to the barn where I keep the RV. I have a 30 amp 110v hookup on that. That cable was there when we bought this place almost 30 years ago.

GM

You need to follow a very specific protocol when using aluminum conductor. The lists of Do's and Don't Do's is long and sometimes arbitrary. Cheat on just one of the points and you will have a fire. Aluminum is satisfactory when installed absolutely to code. BUT BUT BUT I do not see a satisfactory way to join AL to Cu at the female 50 ampere RV socket.

MM49 wrote:
You might want check again. All of the answers are wrong.
MM49


Wire Size Calculator

Careful with that calculator. Copper, single phase, 240v, 50 amp, 10 feet = #14 wire :E

You might want check again. All of the answers are wrong.
MM49


Wire Size Calculator

I hope you are not thinking that you need 220v for an rv. They use 120 v , 50a.

The #6 Alu is too small, I would not use it
#6 copper is used for 50 amps
Either use #2 Alu all the way or use copper all the way,

The minimum wire size for 50A is #6, so you would need a minimum of #6/4 to run a 220v circuit (4 conductors, two hots, neutral, gnd). For a run over 100' long it is advisable to increase the wire size to minimize voltage drop, so you should be looking at #4 copper wire. Aluminum requires upsizing the gauge over copper, so you would need #2 aluminum. So # 2 AL would be OK but #6 AL won't cut it for 50a service. Also agree with others, copper is preferrred over alum.