RV Park 240v vs 208

Npstewart

Senior Member
Do RVs actually use any L-L voltages internally?

Im working on an RV park and there are several that are under construction in my area. I was given some drawings to use as reference and I noticed that the reference designs go out of their way to provide 240v to the RV sites for the 50A receptacles. The reference designs either show a 120/240-1 service that results in a massive service, (or) show a 480v service with single phase transformers.

I know that Shore Power for boats do require 240v because they utilize control transformers internally and if 208v is brought to a boat it could become an issue.

However, from what I can tell, all the loads within an RV are actually 120v. Therefore, a 120/208-3 source would really have no impact. Im sure there is some exception where an RV may have a L-L load however chances are that could likely run off of 208v like most other loads.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
If you read article 551 you will see that there are rec vehicles that use 120/240v 50 amp or 120/208 50 amp. Maybe they use electric heat and a/c....
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Electrician
From what I know, Rvs that need a 30A only have one A/C unit and the 50A ones have two A/C units. But I don't think the two unit ones are L-L just two 120V circuits. You run a 2-pole (L-L) 240V to split the 120V loads.
 

mopowr steve

Senior Member
Location
NW Ohio
Occupation
Electrical contractor
From what I know, Rvs that need a 30A only have one A/C unit and the 50A ones have two A/C units. But I don't think the two unit ones are L-L just two 120V circuits. You run a 2-pole (L-L) 240V to split the 120V loads.
I believe Bill is correct but not sure when it comes to clothes dryers that may be installed.
 

Todd0x1

Senior Member
Location
CA
I work on an annual event where we power 50 or so large RVs for a week from a couple towable diesel generators. All 3 phase 120/208 generators and distribution and 50 amp 4 wire connections for the RVs. I have never seen one of these rigs with any L-L loads.
 

Cow

Senior Member
Location
Eastern Oregon
We're also working on a design for an RV park. After talking it over with a tech from a large RV service center it was determined that even the biggest RV's with dual 50 amp cords still use only L-N loads.

At this point, we are figuring on two services at 208/120v 3 phase.
 

steve66

Senior Member
Location
Illinois
Occupation
Engineer
See 551.40(A). Any Line to Line loads or equipment installed in an RV must have a voltage rating of 208-230 volts.

So 208V will work with any L-L RV load.
 
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