4 prong 30 amp gen to 3 prong welder


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Old 02-10-09, 05:45 PM
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4 prong 30 amp gen to 3 prong welder

I can't seem to find an answer to this question.

I have a generator with a 30 amp 240 volt 4 prong outlet on it (L14-30R).
I have a 240 volt welder rated at 20 amps that has a 3 prong plug on it (not sure what this one is).

The questions: Can these two components be safely connected together? What would be the needed items and wiring if it can be done safely?

I may be wrong but I think there is an issue with grounding and it would be unsafe.

Can I just add a three prong 240 volt plug on the generator?
 
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Old 02-10-09, 06:00 PM
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The L14-30R has two hots, a neutral, and a ground. Your welder does not need a neutral which is why it only has 3 prongs (2 hots and ground) You could use the 30 amp feed to power a small panel then feed the welder off that. My concern is if your welder got "stuck" you could burn up the welder. Unless your welder has some type of overcurrent protection built in. If it did, then I see no issue to making an adapter.
 
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Old 02-11-09, 07:35 AM
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Thanks for the reply.

So if I make a short cord to plug into the gen that the welder plugs into I would be good then?

Can you tell me which blades on the gen would corrospond to the correct blades on the welder?

EDIT:

I suppose I could put some kind of circuit breaker in it to protect the welder in the process.
 
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Old 02-11-09, 05:48 PM
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Originally Posted by makeitso View Post
So if I make a short cord to plug into the gen that the welder plugs into I would be good then?
That is what I would do if your welder has an over current device.

Originally Posted by makeitso View Post
Can you tell me which blades on the gen would corrospond to the correct blades on the welder?
Not really but I can tell you the fat one is the ground. Just use a meter to find the correct ones. Between the ground and the hots you will have around 120 volts. Between the two hots you will have around 240 volts.


Originally Posted by makeitso View Post
I suppose I could put some kind of circuit breaker in it to protect the welder in the process.
It's probably not a big deal because the welder is rated for only 20 amps so it should not draw more than that. But I would still be concerned if something goes wrong with the welder, you could start melting things. Again, this is worse case but that is what we plan for.
 
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Old 02-18-09, 06:07 PM
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OK, I am good to go on this and it works great.

The welder has a 20 amp circuit breaker on it so I should be fine from that stand point.

Thanks for the help and information.
 
 

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