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Discussion Starter · #1 · (Edited)
I could easily have this wrong, but I purchased a home and it had a 30a/240v plug in the garage for a welder or air compressor. There is a dual pole 30a breaker in the house panel.

I would like to use the existing wire(it'd be a heck of a pull to change) if possible to go from this the attached garage.jpg, to this:

http://connecticut-electric.com/product/70bbeed8-30a4-4642-8400-fecad68d4cfb.aspx

I'm sure you know what it should be but for reference inside black wires go from breakers to the outlets, white wires from the outlets to a bar, green wires from the outlets to a bar, and a box grounding screw.

Please correct my thinking as I'm sure its off:

1. Remove 30a dual pole in house, replace with 30a single and 20a single.
2. Black wire between house 30a breaker and rv 30a breaker.
3. Red wire between house 20a and rv 20a.
4. White to White
5. Clear/copper to green and box ground.

*edit* or do I have to do anything at all in the house breaker? Seems like it would be safer to leave as a single and then both would fail if something went wrong between the house panel and the rv panel.
Thanks
 

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Sounds good to me, you will have to change the breakers inside the house as well.

You may be able to leave the 2 pole 30A in the house, since you have a 20A before the 30A you shouldn't have a problem. What do other people think of that?

I have always been against sharing a neutral between two breakers of different amperages but if the wire is sized properly you should be fine because the most the neutral will see is 30A and that is how it orginaly was wired.
 

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I can't see the wiring inside the box but I don't think you would have to change the breaker at your panel.

There is probably an L1 and L2 lugs for the two hot wires, a lug for the neutral and one for the ground.

The breaker in the panel protects the wiring to the RV box and the breakers in the RV box protect the receps.
 

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RV circuits/receptacles are either 30A-120v, or 50A-120/240v

You need to first determine which one it is you need.
 

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The receptacle in your garage is a 50 A receptacle. The wire going to it looks like either 8-3 or 6-3. If it is 6-3, I'd change the breaker in the house to a 50 A double pole, and wire the RV panel in. No problem.
 

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I see that now Darren. Thanks. :thumbsup:
 

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Discussion Starter · #8 ·
The receptacle in your garage is a 50 A receptacle. The wire going to it looks like either 8-3 or 6-3. If it is 6-3, I'd change the breaker in the house to a 50 A double pole, and wire the RV panel in. No problem.
I happen to have a 50amp breaker .... but do I need to? Its only going to feed a 30 amp and 20 amp (which both have inputs).

What does the code say about running different amperages over the same wires/shared neutral?

thanks

Mike
 

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I happen to have a 50amp breaker .... but do I need to? Its only going to feed a 30 amp and 20 amp (which both have inputs).

What does the code say about running different amperages over the same wires/shared neutral?

thanks

Mike
Since the RV box constitutes a single piece of equipment, I would say that it is required to have a single breaker that disconnects it. You don't need to use the 50 A. But I would definitely use a double pole 30 at least, not two single breakers. The two circuits in the RV box have separate breakers anyway. If the circuit already has a 30 A double pole installed, just wire your RV box in and you're done.

RE: Shared Neutral: As long as the neutral can carry the current of the maximum rated leg, then you're fine. But this is a non-issue, because you should use a double pole as the feed breaker.
 
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