50 AMP service revisited

[gojodo]

Ealier this week there was a discussion about 30 v 50 amp service. I would really appreciate to hear how this works. I have a 3075RL 2007 Montana. It has a 50AMP plug for shore power input. Does this mean I have 50 AMP service? I ask this since I know I have no circuits that use more than 30 amps, even the air conditioner. So, do I really just have two lines of 25 AMPs (thinking about the 50AmP wiring) or truly 50AMPs. If anyone has any web sites that help expain this I would love to take a look. Thanks John

[bncinwv]

Try this:
http://www.myrv.us/electric/
Hope it clarifies it for you,
Bingo

[NCFischers]

Electric hookups for RV'5 are 120 volt 30 or 50 amp, not 240 volt that has two 120 volt hot legs.
The larger RV's will have 50 amp capability but can be hooked up to anything smaller without damage. Just remember that you may not be able to run as many things at the same time.

[bncinwv]

Not to be argumentative, but there are several 240V dryer installations that have been documented on the forum. If you measure across the inputs, you can get 240V reading. As they are commonly used there are separate 120 volt feeds (180 degrees out of phase with each other) on the input lines when measured to neutral. Check the link for the 50 amp Service on the above provided link for clarification
Bingo

[ols1932]

In essence, with 50-amp power you have 50 amps on each leg. But it is still only 50-amp power. On our unit, one leg of the 50-amp input goes to a 30-amp breaker that supplies power to all of the rig EXCEPT the washer/dryer (which we don't have). The other leg of the 50-amp input supplies power to a two 20-amp breakers (one for the washer/dryer if we had them, and one which is spare). I rewired our unit so that the AC goes to one of these 20-amp breakers. This means that when we are on shore power the AC doesn't drag power from the other appliances. My wife can run her hair blower at the same time the AC is no. Before I moved it, she could not.

Orv

[bsmeaton]

Truly a confusing topic.

The 30A service for RVs is 30A 110VAC. It is a single 110Volt circuit capable of a maximum of 30Amps.

The confusing part is the 50A service for RVs is actually 50A 220VAC. It is two 110Volt circuits capable of 50Amps each. When you consider that all of the AC appliances on our Montanas are actually only 110VAC, we get a combined benefit of 100Aamp capacity fromt the 50A service.

As Bingo says, you can actually install a 220(240) volt appliance using both sides of the bus on your newer Montana models. Several folks have done this for household type dryers.

It sounds wierd but the 50A 220VAC is actually a standard design. In reality it was the 30A 110VAC service that was adapted specifically for RVs and is rarely, if ever, used elsewhere in the industry with that type of plug. The industrial 30A 110VAC is more like a standard receptacle with a sideways prong.

[fulltimedreamer]

What bingo and Brad said...

[gojodo]

Thanks to all of you. Bingo's web site really helps. Just for clarification, in my 3075RL 2007 Monty the reason I know I can use up to 50 AMPs is because I am wired with a 50AMP plug coming in to the rig, right? If I could only use 30AMPs I would have a three prong plug wired as the shore power input. I assume if I had 30AMP I would also have a maximum of 30AMP Breakers in line. Where in my current system I have some 50AMP circuit breakers. Thanks again to everyone. John

[bsmeaton]

John, your logic is correct.

It would not necessarily apply to some of the pre-2005 units that had the optional 50A service, as that only added a 20A circuit to the other side of the 30A so you could use the 50A pedestal at the park and have a dedicated circuit for your 2nd AC, or in Orvs case on his 2000, a wash machine. On those rigs (our 2003), the Montana breakers were a 30A and 20A rather than 50A and 50A.