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Mr_D · 05-27-2017, 03:43 PM

Years ago we stayed at a campground very near an Indian casino in OR. (not 7 Feathers). It had a normal 50 amp receptacle, but a 30 amp breaker on one leg and a 20 amp on the other!. Not sure what kind of "electrician" did that and what inspector approved it!

Sbrownstein · 05-27-2017, 03:45 PM

Do you really think that an electrician doesn't know how to wire a 30 amp or 50 amp RV outlet? I seriously doubt it. I agree...show him the plug and all will be well.

twinboat · 05-27-2017, 04:19 PM

You are not simply providing 2, 120 volt lines to the coach.

To do that you would need 5 wires, ( L1, N1 ), ( L2, N2 ) and ground. Otherwise both L1 and L2 would be on the same buss. That would overload a single neutral.

With a 240 volt service the L1 and L2 are on opposite legs and share 1 neutral. The neutral only carries the differance between the L1 and L2s current.

If you are drawing 37 amps from L1 and 37 amps from L2, the neutral is carrying 0 amps. If L1 is 20 amps and L2 is 30 amps, neutral is carrying 10 amps.

To get 50 amps to each leg, with only 4 wires, it MUST be 240 volt service.

Hgrace56 · 05-27-2017, 06:40 PM

Quote:

Originally Posted by twinboat

You are not simply providing 2, 120 volt lines to the coach.

To do that you would need 5 wires, ( L1, N1 ), ( L2, N2 ) and ground. Otherwise both L1 and L2 would be on the same buss. That would overload a single neutral.

With a 240 volt service the L1 and L2 are on opposite legs and share 1 neutral. The neutral only carries the differance between the L1 and L2s current.

If you are drawing 37 amps from L1 and 37 amps from L2, the neutral is carrying 0 amps. If L1 is 20 amps and L2 is 30 amps, neutral is carrying 10 amps.

To get 50 amps to each leg, with only 4 wires, it MUST be 240 volt service.

There are not typically 2 neutral conductors.
Since there are only 4 blades on a NEMA 14-50R a fifth conductor would be in necessary

twinboat · 05-27-2017, 07:21 PM

Quote:

Originally Posted by Hgrace56

There are not typically 2 neutral conductors.

Correct ! Two neutral conductors are not needed with 240 volt service.

70ChevelleSS · 05-31-2017, 06:46 AM

Quote:

Originally Posted by MSHappyCampers

A 50A outlet for an RV is two 120VAC 50A circuits! If he hooks it up for 240 you will probably burn up everything in your rig! Either get another electrician that is familiar with this hookup or get the correct wiring diagram to give to this one!

http://www.myrv.us/Imgs/PDF/50-amp%20Service.pdf

50 amp wiring diagram that makes RV electric wiring easy

You're obviously out of your element. Two 120v hot legs, 180 degrees out of phase, yields 240v potential. The 50 amp RV input is a 120/240v input. Use 1 hot leg and the neutral for 120v loads. Use both hot legs for a 240v load such as an electric close dryer.

Sbrownstein · 05-31-2017, 07:03 AM

Personally I think that some people are trying to give an electrician too much information, much of it that they do not themselves understand. Virtually any electrician understands these issues once they see the rig and the plug.

Cooperhawk · 05-31-2017, 07:15 AM

The electrician is correct. I have outlets for both 50 amp 110 volt, and 50 amp 240 volt. The latter is for welders and other equipment that use that voltage. The difference is the receptacle. One plug will not plug into the other receptacle.

Just in my storage barn where I keep the MH I have both receptacles.

Warning! If your plug does not fit a receptacle, do not modify it to fit.

Sbrownstein · 05-31-2017, 07:21 AM

Quote:

Originally Posted by Cooperhawk

Warning! If your plug does not fit a receptacle, do not modify it to fit.

Absolutely...that is why they have different plugs and receptacles!!!!!!

Rollin101 · 05-31-2017, 07:37 AM

It's really pretty simple. It's wired for 240 and the box in your coach takes care of the rest.

Sbrownstein · 05-31-2017, 07:43 AM

Quote:

Originally Posted by Rollin101

It's really pretty simple. It's wired for 240 and the box in your coach takes care of the rest.

Actually, it is split phase and thus can supply either 240 or 120, depending on the breaker configuration. I am sure that you understand, but this is the kind of thing that gets people without electrical experience into trouble. A 3 wire dryer outlet is wired for 240 as well, and no amount of magic can pull 120 from it at the panel.

xrated · 05-31-2017, 10:11 AM

It's actually much simpler than some of you are suggesting.....

Tell them to hire a qualified Electrician that actually knows what the hell he's doing. If he doesn't know something as simple as a basic service for a 50 amp RV application, I'm betting that he won't know much about proper wire size, NEC requirements, etc. I simply wouldn't take the chance on something like this and risk damaging equipment or worse, a possible fire.

Sbrownstein · 05-31-2017, 10:12 AM

Are you telling me that I can no longer "trust the union label?"

MSHappyCampers · 05-31-2017, 11:00 AM

Quote:

Originally Posted by 70ChevelleSS

You're obviously out of your element. Two 120v hot legs, 180 degrees out of phase, yields 240v potential. The 50 amp RV input is a 120/240v input. Use 1 hot leg and the neutral for 120v loads. Use both hot legs for a 240v load such as an electric close dryer.

I obviously didn't state that right. The 240 VAC is there, but the connector is wired to provide two 120 VAC circuits.