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TexasTwoStep · 12-23-2014, 03:12 PM

Someone help me figure this out. I've got a 50 amp rig and have a 30 amp service. I use an adapter to reduce down from 50 to 30 amps. A 50 amp plug has 2 hot wires and 30 amp has 1, right? Are both legs of the 50 amp panel made hot (with 30 amps each) as opposed to all the 30 amp features being on the same leg?

Old Scout · 12-23-2014, 03:23 PM

Essential 30 amps shared on two legs--a 50 amp plug has 4 prongs [2-120VAC hot legs, a ground and a neutral]. A 30 amp RV plug has 3 prongs [1 hot leg, a ground and a neutral]. When you use a 30 to 50 amp "dogbone", the dogbone splits the one 30 amp hot leg coming in and divides it onto the two 50 amp hot legs going out. Using the 30/50 amp dogbone, you only get 30 amps to share on your two 50 amp legs in the coach.

Rocky Larson · 12-23-2014, 03:25 PM

I think it is better said that both legs are hot with 30 amps total, not 30 amps each. That is what the adapter is rated for, not 60 amps.

You can't increase the 30 amp service with an adapter.

So no, all of the 30 amp features are not on the one leg.

**Lt Dan** · 12-23-2014, 03:46 PM

Actually, you need to make sure the "dogbone" you purchase has a crossover to power both legs. Some of the commercially available adapters only power one side of the two legs of the 50 amp panel. I purchased one that only had power to one side. It's easy to check using an ohmmeter. You should have almost zero resistance between the hot lead on the 30 amp plug and BOTH hot legs on the 50 amp socket.

I wound up making my own adapter with a 50 amp female socket, a piece of 10 gauge wire and a 30 amp male plug. In the 50 amp female socket, you just install a jumper between the two "hot" legs. The other posts are correct in that you only get 30 amps total to share between the two circuits, where with 50 amp service you have 50 amps to each side for 100 amps total.

wa8yxm · 12-23-2014, 06:04 PM

When you plug a 50 amp rig into a 30 amp outlet using an adapter the two hot pins are simply jumpered together... They SHARE the 30 amps.

Likewise when you plug a 30 amp rig into 50 amps, one lead is not connected.

YC1 · 12-23-2014, 06:09 PM

Is this 30 amp outlet already checked out to make sure it is not actually a 220 volt outlet? Others have answered your question but warning lights are going off in my head.

TexasTwoStep · 12-24-2014, 05:23 AM

Quote:

Originally Posted by YC1

Is this 30 amp outlet already checked out to make sure it is not actually a 220 volt outlet? Others have answered your question but warning lights are going off in my head.

Actually a friend asked me this and I got confused. He is wanting to plug his 50 amp plug via the 30 adapter into the outgoing side of his MS2000w inverter when off shore power and asked me if I thought it would work similar to being on 30 watt shore power.

Thanks for the responses.

Wizard · 12-24-2014, 06:23 AM

Quote:

Originally Posted by YC1

Is this 30 amp outlet already checked out to make sure it is not actually a 220 volt outlet? Others have answered your question but warning lights are going off in my head.

30 amp RV is always 1-hot, 1-Neutral and 1-ground and always 120 volt. No way to get 220volt with 1 hot wire.

YC1 · 12-24-2014, 08:00 AM

Quote:

Originally Posted by Wizard

30 amp RV is always 1-hot, 1-Neutral and 1-ground and always 120 volt. No way to get 220volt with 1 hot wire.

THAT is my point. If the op has a unknown "30 amp" outlet that has not been checked to see that it is an RV outlet he may be in for some serious problems. Too many people have found that out the hard way.

YC1 · 12-24-2014, 08:03 AM

Gary, plugging your own shoreline into your inverter is possible but remember you are now powering your charger and would need to open the breaker that feeds that line. Seems a bit strange to want to do this but I can see a case where you might want outlets that are not run by the inverter to be powered.

Hope this is clearer than mud.