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Replacing NEMA 14-50R w/NEMA 10-30, then attach Welder Leads that have 6-50R/P

Replacing NEMA 14-50R w/NEMA 10-30, then attach Welder Leads that have 6-50R/P

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Old 07-09-11, 11:20 AM
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Replacing NEMA 14-50R w/NEMA 10-30, then attach Welder Leads that have 6-50R/P

I am replacing a 240 volt Nema 14-50R (3 wire plus ground) female with a Nema 10-30 female (3 pole, 3 wire, non grounding) receptacle. I have welder leads that will have a Nema 10-30 male plug and a Nema 6-50R female receptacle. The welder has a Nema 6-50P Male plug. It looks like the Nema 6-50R/P has a ground, a positive, and a negative post. If that is correct, how do I go from the three wire plus ground (Nema 14-50R)to the Nema 10-30 then to the Nema 6-50P? Thanks.....
 
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Old 07-09-11, 11:31 AM
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It looks like the Nema 6-50R/P has a ground, a positive, and a negative post.
No, two hots and a ground. Explain why you are trying to replace a 50 amp plug with a 30 amp plug. If it is to use a welder rated 50 amps on a 30 amp dryer circuit it is a bad idea. Neither the breaker or wiring are rated for your welder.
 
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Old 07-09-11, 11:48 AM
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I already had the leads with a Nema 10-30 male plug. Thought that would work and would just work to that end. What you are saying is: (1) don't replace the Nema 14-50R (2) put a Nema 14-50P instead of the Nema 10-30 male plug. Everything else should then work? If that is correct....how do I wire the three multi strand 10 gauge leads to finally get to the two hots and a ground for the Nema 6-50? The breakers are 50 amp.... Thanks for the quick response.
 
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Old 07-09-11, 12:50 PM
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No. If you have a device (welder, etc). that has a 50 amp plug then check the name plate. If the name plate says it can draw more the 40 amps you need a 50 amp receptacle on a 50 amp breaker wired with #6*. A 30a dryer receptacle doesn't come even close to that. What I am say is you need to run a new circuit for the welder assuming the plug that is on it is correct.

*In some cases #8 hard wired but in a residential setting best to match wire size to breaker.
 
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Old 07-09-11, 01:21 PM
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The welder has the 6-50P plug. Name plate says it can draw 47.5 amps. The receptacle on the wall is a 14-50R (3 wires plus a ground wire) connected to 50 amp breakers. I will get a 14-50P plug on one end of the leads to plug into the wall (14-50R). On the other end of the lead, I will put a 6-50R female receptacle. The welder has a 6-50P plug already on it that I will plug into the female end of the lead. Is that correct? How do I go from three wires plus ground (14-50 R/P) to the two wires plus ground (6-50R/P). Do I just use two hot wires (side slots) and ground (top round) on the 14-50P, then wire the 6-50 R/P with those two hot and one ground wire?
 
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Old 07-09-11, 01:26 PM
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Why not just replace the welder plug with a 14-50? It'll be alot cheaper.
 
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Old 07-09-11, 01:44 PM
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Originally Posted by Justin Smith View Post
Why not just replace the welder plug with a 14-50? It'll be alot cheaper.
I want to be able to use the 50 ft leads so that I can weld outside of the garage. Plus...that would be way too easy......
 
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Old 07-09-11, 02:49 PM
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How do I go from three wires plus ground (14-50 R/P) to the two wires plus ground
No connection to the silver "W". silver screw. If you are using 3 conductor service cable (black, white, green) the white is used as one of the hots, either X or Y.

Just curios you referenced NEMA 10-30 in your first post. Is this a new plan?
 
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Old 07-09-11, 03:13 PM
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Different plan from the original post. It was the plan that I was trying to say in post #3, after your first post telling me about using the 30 amp when I should stick with the 50. Just didn't get it across the way I needed to. I think you have me all fixed up now. As you can tell, I'm not an electrician. Actually hate messing with it. I like working with stuff I can see before it bites me. Really do appreciate your help......
 
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Old 07-09-11, 04:06 PM
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Glad you are on the right track. Yep, some times I read posts too fast, sorry about that. Just a check you are using at least #10 cable* and it is service cable (example SOW) not Romex, correct?

*Assumes a short duty cycle welder.


Source 2008 NEC
 

Last edited by ray2047; 07-09-11 at 05:01 PM.
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Old 07-09-11, 05:30 PM
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Yep....I think it is 10 or 8. The electrician knew what the intent was for the outlet when I had the garage built. I will use your table and make sure everything is OK. Again...thanks for your help. First time I've used the DoItYourself forum. Really do like it. Know I will be back.....
 
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Old 07-09-11, 06:20 PM
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Actually I was writing about the cable for the extension cord. Good luck and come back if you have anymore questions.

The electrician knew what the intent was for the outlet when I had the garage built.
Actually I was writing about the cable for the extension cord.
 
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