RV Park 240v vs 208

[Npstewart]

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.

 

[MAC702]

I've never seen an RV with 2-pole loads, and I've worked on several, old and new.

 

[Dennis Alwon]

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....

 

[oldsparky52]

551.72(C)

I believe that is saying you must feed a 50-amp 125/250V receptacle with 120/240 not 120/208. Same as 555.19(A)(3), the informational note is note worthy.

 

[Little Bill]

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]

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.

 

[yuhong]

Be aware of EV charging, which tolerates both but usually is faster at 240V.

 

[Todd0x1]

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.

 

[LarryFine]

And a dryer works perfectly on 208v, with the element at 75% of 240v power.

 

[Cow]

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.

 

[ActionDave]

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.

:thumbsup:

 

[ActionDave]

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.

:thumbsup:

 

[ActionDave]

Multiquote is not working after the update.

 

[steve66]

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.