30amp double pole breaker for 50amp camper?

[ependydad]

I was parked at my in-laws and my father-in-law had a welder plug in the garage. It was wired for 240v with a double-pole breaker in the basement.

He changed out the breaker to be a single pole 30amp breaker. And then we changed out the outlet to be a 120v 30amp twist-lock welding outlet like my generator has. I converted that to my 30amp dog bone and then put my 50amp dog bone onto that and plugged in. Life was good.

His brother has owned campers for many years and said we could have wired it so that we could use 2 legs of 30amp service and put a 50amp outlet on the wall. He does it, and it works great. I've read enough here over the years to say, "yeah, that scares the heck out of me".

Everything I read about 50amp outlets, 4 wires were required: 2 hots, a ground, and a neutral. We only had 3 wires.

Could we have done what the brother suggested? Somehow wired it up so that I'd have 2 legs of 30amp service?

[youroo]

Oh boy another "Pop Corn Post"! These always go into areas of "Bad Saftey Advice"! Youroo!!

[donanddona]

This is why we promote surge guards. Know when your smart enough to call an certified technician to do the job.

[ependydad]

Originally Posted by youroo

Oh boy another "Pop Corn Post"! These always go into areas of "Bad Saftey Advice"! Youroo!!

Dang. I swear it's not my intention.

I just couldn't figure out how it could possibly work.

Originally Posted by donanddona

This is why we promote surge guards. Know when your smart enough to call an certified technician to do the job.

That's the thing. I have a buddy who IS a certified electrician and fulltime RVer. He had mentioned something similar about setting up a 50amp plug with 2 x 30amp legs at his in-law's house. I didn't ask for details then as it wasn't directly pertinent at the time.

Though, I agree. I do have a hard-wired EMS and strongly suggest them for everyone.

[Steve-W]

Well it could be made to work by using the existing ground wire as the neutral and ground. Of course the max power avaliable would be 7200 watts vs 12,000.
Would it work, yes. Would it be safe and make code NO. You made the right decision by doing what you did.

As you said you need 4 wires of the proper gauge for a 240 volt split phase outlet.
There is a possibility the ground wire in the exsisting run is a smaller gauge than the hot wires, that could turn out bad if used as the neutral.

[ependydad]

Originally Posted by Steve-W

Well it could be made to work by using the existing ground wire as the neutral and ground. Of course the max power avaliable would be 7200 watts vs 12,000.
Would it work, yes. Would it be safe and make code NO. You made the right decision by doing what you did.

As you said you need 4 wires of the proper gauge for a 240 volt split phase outlet.
There is a possibility the ground wire in the exsisting run is a smaller gauge than the hot wires, that could turn out bad if used as the neutral.

I definitely understand the less watts available. No worries there.

And yes, we talked about the 3 vs. 4 wires. He did say you'd just bind the ground and neutral together. Wire-size is interesting, I hadn't thought about that. Any other reason why you wouldn't/shouldn't do this?

[Steve-W]

Originally Posted by ependydad

I definitely understand the less watts available. No worries there.

And yes, we talked about the 3 vs. 4 wires. He did say you'd just bind the ground and neutral together. Wire-size is interesting, I hadn't thought about that. Any other reason why you wouldn't/shouldn't do this?

“Binding” the neutral and ground together besides being against code big time is a very unsafe way of doing this. It leaves your rig witnout any dedicated grounding in case something goes wrong. There are ways around this but all are in violation of code. Assuming the ground wire is the same ga as the hot wires (10ga for 30 amps) you most likely would have no issues.
You can also run into issues depending on the other wiring in the building, single mailn panel, sub panels, etc all have different grounding schemes.
Personally I would never do this.

[ependydad]

Sounds good. Thanks for the replies, Steve.

It didn't sound right to me, but I thought I'd throw it out there.

[Springerdad]

Originally Posted by ependydad

I definitely understand the less watts available. No worries there.

And yes, we talked about the 3 vs. 4 wires. He did say you'd just bind the ground and neutral together. Wire-size is interesting, I hadn't thought about that. Any other reason why you wouldn't/shouldn't do this?

I believe tying the ground and neutral together creates a "bootleg ground" that Mike Sokol describes in his RV electrical book.

[mikebecker80]

I have that at home. 30 amp breaker, 4 wire #10 wire to a 50 amp plug. Have used the AC a few times, no trouble.

[SailorSam20500]

My thought is that the only way to make use of the,existing wiring and have both hot legs, would be to add a properly sized wire to handle the nuetral.

[Steve-W]

Since you have 4 conductor wire that is a safe workable solution. Although it does violate NEC code. Not so with the 3 conductors ependydad has to work with.

[mikebecker80]

I only have 30 amp box in garage. But wrote 30 amp on the 50 amp outlet.

[Steve-W]

Originally Posted by SailorSam20500

My thought is that the only way to make use of the,existing wiring and have both hot legs, would be to add a properly sized wire to handle the nuetral.

Would work if the existing wire is in conduit, with enough space for an additional conductor.

[Tom48]

Originally Posted by youroo

Oh boy another "Pop Corn Post"! These always go into areas of "Bad Saftey Advice"! Youroo!!

If someone WHO UNDERSTANDS what they are doing wires a 50 amp type socket on only a double 30 amp circuit, as long as it is fused (breakered) correctly for the gage of wire in the run, there should no problem.

You would have twice as much current as if you wired a 30 outlet on just the one "hot" then ran a dog bone (plug adapter) to your coach. Just know that the "breaker on the pole" so to speak, will blow long before your 50 amp Mains in the coach, so plan accordingly.

And as mentioned, always safer to good surge guard or Progressive Dynamics device for further protection of your valuable coach.

[Larry-NC]

Originally Posted by Steve-W

Would work if the existing wire is in conduit, with enough space for an additional conductor.

Well, if the existing wiring run is in conduit, the conduit serves as ground. Only three wires would be needed for the trailer outlet: two hots and a neutral.

But if a 240 VAC welder were wired in conduit, there would only be two wires present, the two hot sides of the 240 VAC, and three would be needed. One too few, again.

This would be #8 AWG wire, seriously heavy stuff. You might not be able to pull three wires through the existing conduit, even if you pulled the other two out and then tried to pull three at once. Three #8 conductors is the maximum allowed in 1/2" galvanized conduit (if I'm reading the chart right).

Larry

[Springerdad]

Originally Posted by youroo

Oh boy another "Pop Corn Post"! These always go into areas of "Bad Saftey Advice"! Youroo!!

Why would you want to say that?

[Steve-W]

Originally Posted by Larry-NC

Well, if the existing wiring run is in conduit, the conduit serves as ground. Only three wires would be needed for the trailer outlet: two hots and a neutral.

But if a 240 VAC welder were wired in conduit, there would only be two wires present, the two hot sides of the 240 VAC, and three would be needed. One too few, again.

This would be #8 AWG wire, seriously heavy stuff. You might not be able to pull three wires through the existing conduit, even if you pulled the other two out and then tried to pull three at once. Three #8 conductors is the maximum allowed in 1/2" galvanized conduit (if I'm reading the chart right).

Larry

This is true assuming metallic conduit installed correctly. As always there are so many options. Some are good and some not so good.

[wildcatter]

I'm guessing what the FIL's brother was using is a 4 plug/wire outlet, I ran power to my garage, I used a 50 amp 240 volt four wire plug to plug my camper into, I then built an adapter for my 50 amp welder (no neutral) and plasma cutter and ran an extension box off the 50 amp service for the 30 amp 120 volt welder or a 30 amp camper, I have the 30 amp circuit breaker'd at 30 amps.

[cavie]

Originally Posted by ependydad

I was parked at my in-laws and my father-in-law had a welder plug in the garage. It was wired for 240v with a double-pole breaker in the basement.

He changed out the breaker to be a single pole 30amp breaker. And then we changed out the outlet to be a 120v 30amp twist-lock welding outlet like my generator has. I converted that to my 30amp dog bone and then put my 50amp dog bone onto that and plugged in. Life was good.

His brother has owned campers for many years and said we could have wired it so that we could use 2 legs of 30amp service and put a 50amp outlet on the wall. He does it, and it works great. I've read enough here over the years to say, "yeah, that scares the heck out of me".

Everything I read about 50amp outlets, 4 wires were required: 2 hots, a ground, and a neutral. We only had 3 wires.

Could we have done what the brother suggested? Somehow wired it up so that I'd have 2 legs of 30amp service?

Bare grounds and insulated neutrals are 2 different things and do 2 different jobs. The neutral carries AC. The ground carries unintentional AC.

You cannot make it work! The white wire of the 30 amp cord is neutral. You cannot put 120 volts on the line as it is hooked up to the neutral bus. Sparks will fly. I wish people would leave electric to the professionals. Then again, I made a pretty good living for 45 years fixing amateurs screw ups.