RV Park 240v vs 208

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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

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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

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Location
Tennessee NEC:2017
Occupation
Semi-Retired 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
Occupation
Electrician
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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