I want to add a 30 amp RV plug to my shop. The supply for my air compressor is close to the area where I want the plug and is a 30 amp 220v circuit. My understanding is the RV plug has 3 prongs, one for ground, one for 120v and one for the neutral. Can I use one hot leg and the neutral from the compressor circuit? The compressor should have 2, 120v hot legs and the neutral and ground legs. I just need to know if I can use part of it.
Looking for advice on RV plug wiring
- Thread starter sanddan
- Start date
Another question, for a 50 amp 12v RV plug you have 4 prongs. Two prongs are 120v each and one is neutral and one ground. Could I use my 50 amp 220v welding circuit? For that the two 120v legs are combined to get the 240v but that is done in the plug wiring I think so can I use the same 120v legs to supply the RV plug?
sberry
Banned
The comp and welder circuits do not have a neutral in them.
sberry
Banned
A 120V RV is kind of a special circuit. It has a unique outlet, can use a 2 conductor 10 wire plus ground. A 50 is similar to a range circuit. Needs a big heavy *** wire, 3 conductor plus ground. The welder and the comp are each 2 conductor plus ground. But the voltage is different than the comp. Run a new wire for this.
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nsula_country
Well-known member
+1
Run a dedicated 30A, 120v circuit. Use a 30A, 1 pole breaker. Use #10 wire. Your compressor circuit does have 2 legs of 120v. It also has a 2 pole breaker and no neutral.
For a 50A RV circuit, you need to run #6 for L1, L2, N and #10 for ground.
They are special circuits that aren't common in a shop. They need to be dedicated and wired proper for safety and to prevent equipment damage.
Now, what I did (non-residential shop) was run #6 L1, L2, N and #10 ground with a 2P 50A breaker. Branched off in a junction box (Split bolts) and made my 50A RV drop then continued to the welder location. At this location I have another junction box (split bolts) and have a 3 wire and a 4 wire 50A receptacle. Some will say #6 is overkill on a welding circuit, but this is more of a 50A utility circuit with 3 receptacles.
The reason for the 2nd 50A 4 wire receptacle was incase I ever decide to convert to electric brewing, I will have 2 locations I can plug in brew stand.
CT
Run a dedicated 30A, 120v circuit. Use a 30A, 1 pole breaker. Use #10 wire. Your compressor circuit does have 2 legs of 120v. It also has a 2 pole breaker and no neutral.
For a 50A RV circuit, you need to run #6 for L1, L2, N and #10 for ground.
They are special circuits that aren't common in a shop. They need to be dedicated and wired proper for safety and to prevent equipment damage.
Now, what I did (non-residential shop) was run #6 L1, L2, N and #10 ground with a 2P 50A breaker. Branched off in a junction box (Split bolts) and made my 50A RV drop then continued to the welder location. At this location I have another junction box (split bolts) and have a 3 wire and a 4 wire 50A receptacle. Some will say #6 is overkill on a welding circuit, but this is more of a 50A utility circuit with 3 receptacles.
The reason for the 2nd 50A 4 wire receptacle was incase I ever decide to convert to electric brewing, I will have 2 locations I can plug in brew stand.
CT
What I was thinking about. My 50 amp circuit is 12' and a wall away from where the RV plug would be so a short run. The L1, L2 and ground are already there, all I would have to do is fish the #6 N from the main panel. The electrical pipe was laid under the concrete floor so I just have to check if I have enough room for another wire.
nsula_country
Well-known member
Though you said 30 amp comprssor circuit?? Don't need #6 for 30 amps...
Not a 50 amp circuit in a conduit.
Falcon67
Well-known member
I ran a "50A" circuit for our race trailer. It's fused at 30A but is a full 4 wire circuit to provide the proper 240V power to the RV cable. Mainly for lights and to keep the fridge cold LOL. Even the AC only pulls 13A so a full 50A circuit wasn't required. Run to a weather box on the outside of the shop.
Crazyjake8493
Well-known member
I wouldn't bother trying to add a neutral to the welder circuit. Just run a new, proper circuit with correct wire as nsula already suggested and be done with it.
wyliesdiesels
Well-known member
No you cant do that.
a 240v compressor circuit doesnt have a neutral. And you cant take conductors from one circuit and use them with conductors for another circuit.
The proper way to do this is to run a dedicated circuit.
BTW what is the HP rating on the compressor motor?
If the RV outlet is 30a, then no you cant do that since the circuit is 50a.
Run a dedicated circuit.
you would also need to put in a subpanel with a 30a single pole breaker to protect the 30a RV outlet.
There is no proper or code permissible way to willy nilly
this or cobble it together to save a few dollars on wire.With the time you have already taken to think about it, post on a forum and respond, I couldve driven to home depot(10 min away) bought the parts and materials i needed and be driving back home.
sberry
Banned
What is it you now want, 30A or 50? They are 2 distinctly different RV circuits. Yes in theory you could use the welder circuit if it is piped, number 6 and you can add another wire.
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wyliesdiesels
Well-known member
He can use the welder circuit IF the RV circuit is 50a.
sberry
Banned
I am not exactly sure what he wants, talks about 2 different things. As far as I know there are only 3 ways for RV, common cord to 120 20, a special 30 120v and 240 50. I do not think,,, or never worked on one had 30A 240.
38Chevy454
Well-known member
I have an RV and this is how the RV circuits work: 30 amp is one leg 30a @ 120v, with a neutral and ground. 50 amp is two legs 50a @ 120v, being opposite phases, along with neutral and ground. The 50a has 12000 watts total power (2 x 50) x 120. 30a has only 3600 watts total power (1 x 30) x 120.
There is 240v available across the 50a hot legs, but an RV does not use more than one leg for any item.
Just for technicality there are some very high end motor homes that do use 240v but it is rare and not typical.
A welder circuit could be used if it has a neutral (4 wire).
Sent from my iPhone using Garage Journal
There is 240v available across the 50a hot legs, but an RV does not use more than one leg for any item.
Just for technicality there are some very high end motor homes that do use 240v but it is rare and not typical.
A welder circuit could be used if it has a neutral (4 wire).
Sent from my iPhone using Garage Journal
Simple soulution is wire it as 50amp 220/240v outlet and use a conversion plug to tap 30amp 120v RV. Best of both worlds. For $20.
https://www.amazon.com/Marinco-5030ARV-50-Amp-Adapter/dp/B004VRNNHU
Or install a box with 50amp 240v, 30amp 120v and 15(or 20)amp 120v outlets and have all worlds covered for not much more in cost.
My issue with that would be the main panel is full (as to breaker locations) and is 50' away from the RV parking bay. Some of the circuits are under utilized, for example only 1 plug on a 15 amp circuit, but changing them would be a major re-wire job in the panel. I'd like to do as few changes as possible. If I was starting from scratch I would do as you suggest.
I don't think I was very clear on what I have to work with and what I need for the result.
1. My 200 amp main panel is about 50' away (opposite end of building) and does not have an open breaker spot for a new circuit without re-wiring the panel.
2. The majority of the electrical wire runs were done in plastic pipe that was buried in the gravel before the concrete floor was poured. Most are either 1" or 3/4" depending on how many circuits were runs and the wire gage. All this work was done by a licensed electrican.
3. Some of the circuits are under utilized in the panel, having only one plug for example. When the building was built 25 years ago a plug and light on 2 separate circuits had to be wired in to allow the power company to hook up the service.
also, some lighting circuits have only 1 or 2 lights due to shop laylout at the time. The 200 amp service IS NOT over used, just not as efficient as it could be.
4. 12' from the RV parking bay I have a 50 amp 240v circuit for the Tig welder. This circuit is only used during a fab project, maybe 4-5 times a month at most.
5. My air compressor is located in the RV parking bay and has a dedicated 30 amp 240v circuit. I believe the pipe in the floor that serves this outlet also has a 20 amp 120v circuit for the RV bay. This is what I'm currently using for power to the RV. With this many wires in a 3/4" line I doubt there's room for any more wires there.
6. My RV has a 50 amp cord. 50 amps will run all of the RV circuits including the AC. I have a 30 amp to 50 amp adapter cord and a 15 amp to 50 amp cord. I've been using the 20 amp adapter which has been ok for charging batteries and running the fridge. I haven't tripped a breaker during the 6 months of using it this way.
7. I would like a full 50 amps so I can use the AC if needed (say for guests staying with us) but would settle with a 30 amp service. Even though the 15 amp service has not had an issue so far I think it is marginal.
Knowing all this it seems like using the welder circuit for the two 120v hot feeds and ground and then pulling an additional wire for the neutral would be the simplest solution to supply the RV bay. I can add a small panel near the welder plug if that is the best way to organize the wiring.
The only issue I see is if tried to weld at full power when the RV's AC was running. Something I can easily avoid as I don't work in the shop when it's that hot out anyway. Am I missing anything?
1. My 200 amp main panel is about 50' away (opposite end of building) and does not have an open breaker spot for a new circuit without re-wiring the panel.
2. The majority of the electrical wire runs were done in plastic pipe that was buried in the gravel before the concrete floor was poured. Most are either 1" or 3/4" depending on how many circuits were runs and the wire gage. All this work was done by a licensed electrican.
3. Some of the circuits are under utilized in the panel, having only one plug for example. When the building was built 25 years ago a plug and light on 2 separate circuits had to be wired in to allow the power company to hook up the service.
also, some lighting circuits have only 1 or 2 lights due to shop laylout at the time. The 200 amp service IS NOT over used, just not as efficient as it could be.
4. 12' from the RV parking bay I have a 50 amp 240v circuit for the Tig welder. This circuit is only used during a fab project, maybe 4-5 times a month at most.
5. My air compressor is located in the RV parking bay and has a dedicated 30 amp 240v circuit. I believe the pipe in the floor that serves this outlet also has a 20 amp 120v circuit for the RV bay. This is what I'm currently using for power to the RV. With this many wires in a 3/4" line I doubt there's room for any more wires there.
6. My RV has a 50 amp cord. 50 amps will run all of the RV circuits including the AC. I have a 30 amp to 50 amp adapter cord and a 15 amp to 50 amp cord. I've been using the 20 amp adapter which has been ok for charging batteries and running the fridge. I haven't tripped a breaker during the 6 months of using it this way.
7. I would like a full 50 amps so I can use the AC if needed (say for guests staying with us) but would settle with a 30 amp service. Even though the 15 amp service has not had an issue so far I think it is marginal.
Knowing all this it seems like using the welder circuit for the two 120v hot feeds and ground and then pulling an additional wire for the neutral would be the simplest solution to supply the RV bay. I can add a small panel near the welder plug if that is the best way to organize the wiring.
The only issue I see is if tried to weld at full power when the RV's AC was running. Something I can easily avoid as I don't work in the shop when it's that hot out anyway. Am I missing anything?
75gmck25
Well-known member
If the conduit is accessible on both ends so that you could pull new 6/3 copper wiring in the conduit running to your TIG welder location, then replace the existing receptacle with a subpanel and breaker it at 50 amps in the main panel. Then run all your circuits (new and old) off that subpanel. This solution is safe, and allows you the flexibility to have several different types of circuits and receptacles (120V vs 240V, 30 amp vs. 50 amp, etc.), all off the same subpanel.
Bruce
Bruce
Are you thinking to pull new wire because the old wouldn't be long enough?
A subpanel sounds like the best solution. Currently I have both a 30 amp and 50 amp welder plug hooked up for the welders. The box's are pretty full as is. Time to do some rearranging.
Thanks to everyone who chimed in with feedback.
You've been told the "what", but not all of the "why" - you need to read AT LEAST page 101 of this
https://www.mikeholt.com/instructor2/img/product/pdf/1259687476sample.pdf
that'll tell you the "why" for most of the advice given so far... Steve
https://www.mikeholt.com/instructor2/img/product/pdf/1259687476sample.pdf
that'll tell you the "why" for most of the advice given so far... Steve
Thanks
dcg9381
Well-known member
I've done several. If you have a 30A plug, your RV is 120V, not 240V. Don't make a very common mistake.
If you install a 50A 240V RV outlet, you can adapt it to 30A by a simple cord available in every RV park. However, it's really not overload protected.
Amazon has a great 50A/30A/20A box for about $110 that is outdoor rated - that's what I would recommend and have installed several times. Comes with breakers.
If you install a 50A 240V RV outlet, you can adapt it to 30A by a simple cord available in every RV park. However, it's really not overload protected.
Amazon has a great 50A/30A/20A box for about $110 that is outdoor rated - that's what I would recommend and have installed several times. Comes with breakers.
mike93lx
ALLIANCE MEMBER
Didn't feel like reading the thread, huh?
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sberry
Banned
I was going to comment on this due to another post but figured it might get convoluted. It is overload protected in this case. It is a listed adapter. The 30A that is connected to it is the thermal and the 10 wire is sufficient to be short circuit protected at 50.
sberry
Banned
I don't have glasses to look at a plug chart but is the 30RV configuration specific to RV or is it used elsewhere?
wyliesdiesels
Well-known member
specific to RV- TT30 is not used for anything else
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sberry
Banned
I thought so, its so specific should have overcurrent protection after it in the trailer. The only travel that doesn't is 120V in pop ups that come 15 end.