Question for the electricians out there.

The conduit B to C is going to have 7 or 8 (depending on whether the portable generator is 120v or 120v/240v) large wires. You are going to need VERY large conduit for that many large wires.

The 7kw generator is about 55 amps. You are going to need at least 6g wires for the hot wires and neutral wires, and at least 10g for the grounds.

According to this CHART you are going to need at least 1.25 inch conduit for the shared run. You may be able to get by with 1 inch for the non-shared runs.

Please note that I am not an electrician.

Bull Rider wrote:
Consider if you will also want a 120 volt drop at the 50 amp RV panel. That might require an extra wire. I don't think you can pull a 120 volt leg off of the dedicated 220 feeds. But I'm not certain of this, but it's something that would be easy to do if it's part of the plan.

When I ran a pedestal for my MH, I used a 50/30/20GFI even though I only have a 30 amp RV. Planning for growth.

I wired it in the breaker box with a 240v 50amp tandem breaker and ran three 6g wires for current carrying and one 10g wire for ground. They then feed 3 breakers in the pedestal. A 50 amp tandem breaker, a 30 amp breaker, and a 20 amp breaker. The 30 amp and 20 amp breakers are on separate legs. Theoretically, I could pull 80 amps on one leg and 70 on the other, but the 50 amp breaker in the main box only allows 50 amps total. I did not want to upsize the wires enough for an 80 amp tandem breaker.

Just pull the wire. May as well have an electrician do it based on expected use. Include a permit and inspection. I think there is more to it than just conduit size.

either run some 4/4seu/r alum cable which is large enough for the 70 amps or wait and run the conduit on the wall after finishing. I built a new workshop last year and ran conduit on the walls. You can only predict what your needs are and reality sets in and you have to add or move things anyway. I chose conduit because as an electrician (retired) I wanted to make a remembrance of the type of work that I was capable of, and the ability to make changes if necessary.

A 50 amp 4 wire setup will run both 240v and 120v. You have 2 hot, 1 neutral and 1 ground. Hot to hot gives 240v. Hot to neutral gives 120v.

Consider if you will also want a 120 volt drop at the 50 amp RV panel. That might require an extra wire. I don't think you can pull a 120 volt leg off of the dedicated 220 feeds. But I'm not certain of this, but it's something that would be easy to do if it's part of the plan.

Have You considered using Tech Cable rather than conduit?

DougE wrote:
Advise the electricians whether you plan to pull 4-conductor cables or individual THHN wires.

I'm hoping the electricians will advise me.

While you are waiting for a pro to respond take a look at http://www.electriciancalculator.com/

Advise the electricians whether you plan to pull 4-conductor cables or individual THHN wires.