Welder Amperage Needs

[tomshep]

I just finished reading a few threads about guys running welders and putting them on 50 amp circuits.

The reason I am bringing this up is I just went through this same scenario and discussed it in a different titled thread.

Anyway, I have a Millermatic 210 mig welder. It came from Miller with a 50 amp plug. I researched it and found out the unit is designed for a 30 amp circuit. I called Miller tech line and they told me in the welding industry it is normal to put a 50 amp plug on the unit, regardless of whether it needs 20, 30 or 50. Same goes for plasma cutters.

So, this long explanation is to ask those of you that are saying you are running your welder on a 50 amp circuit, is it because of the plug it comes with or are you actually going by the manufacturer's requirements?

The tech also told me most welders are internally protected to avoid damage if you actually plug into a true 50 amp circuit.

Tom

 

[pattenp]

I don't know why a tech would tell you that. If the welder requires a 240V connection capable of providing 30A then plugging it into a 240V outlet capable of 50A will not hurt the welder. I don't understand the internal protection from being plugged into a 50A 240V circuit.

 

[41ratrod]

I do maintenance for a metal fabricating co. and all our welders are on 30amp.
some a 220 and most are 480 3ph.
I've got mine on 30amps.

 

[nso123]

The only thing I can see that the unit would be protected from would be in the case of being on a circuit that allows the unit to get too hot before tripping the breaker. I have only heard of this in lighting circuits where the lights were getting too hot without any circuit breaker protection.

 

[sberry]

I don't know why a tech would tell you that. If the welder requires a 240V connection capable of providing 30A then plugging it into a 240V outlet capable of 50A will not hurt the welder. I don't understand the internal protection from being plugged into a 50A 240V circuit.

If the machine comes with a 50A plug it can go on a 50A circuit. Small wire feeders (not AC buzzers) have their own thermal protection for internals and 12 wire that makes them allowed for 50A. In my place there are "homes" for them, usually a 10 30. I have a couple of other 50A in locations outside the welding area for occasional use and added a recept to my hoist for light welding, cars/trucks. The "home" for larger machines have 50A and one 100A for tig.
I finally moved some stuff around that had been sitting in same placew for years, got rid of 2 carts, stacked the HH210 and the plasma on the Synchro, moved the stick, recvonnected it to the "loom" (has a remote set of leads), this all allowed relocation of my tool box in this area that was always out in the way and reduce the tendancy to walk behind it. The little red SP rides mtybench most of the time, can be wheeled to the hoist and is usually the machine that gets moved if there is a need, the stick has lead to reach out door and plasma has 50 foot cord. The littlke red stick was really a pain where is was at, this also reduced some wiring. Bought another recept last night to make up one more pendant for this system. Found a piece of 10/3 cord for 85 cents a foot, I was all out of 10.

 

[sberry]

It really is a good idea to ask about particular machines, main reason is the language used in owners manuals. It is or may be confused by those not familiar with code and NEMA, it is written for the pro and personally I think they should do away with a couple of the minimums which do not do much other than add confusion, there should be a layman's recommendation which could exceed code. So many of these are marketed to diy that I cant see some real help in the manuals hurting much.

 

[pattenp]

I understand the internal thermal protection, but the below statement from the OP made me think that the tech said the welder would internally trip by just plugging it into a 50A circuit.

"The tech also told me most welders are internally protected to avoid damage if you actually plug into a true 50 amp circuit."

 

[tomshep]

I understand the internal thermal protection, but the below statement from the OP made me think that the tech said the welder would internally trip by just plugging it into a 50A circuit.

"The tech also told me most welders are internally protected to avoid damage if you actually plug into a true 50 amp circuit."

Sorry, I wasn't clear on that.

The Miller tech said the units were internally protected so you couldn't damage the unit by running it at 50. I guess so it wouldn't overheat with prolonged use? The same principle as an electric motor with a reset button.

Tom

 

[Highbeam]

I installed a 50 amp 240 receptacle for my Lincoln AC 225 buzzbox that comes with a corresponding 50 amp male plug. The 50 amp receptacle is fed by a 50 amp breaker via 6 gauge wire. Why not make all 50 amps available to a 50 amp receptacle? The breaker protects the wire.

Never occured to me to go with a lower amp circuit since I had plenty of spare 6/3 laying around. I don't even know if the lugs in the 50 amp receptacle would take the tiny wire.

 

[Charliekilo]

I must be missing something? Why is it an issue? Unless you need to make a really long run. Number 6 is about twice number 10. If you do 50 amp you will not be sorry later. On a long run your line lose could give a 30 amp circuit grief.
You can do like I did. I bought a big spool of black wire from H D and ran 3 pieces in conduit. Used colored tape to mark each piece. I have 1/2 the spool left and it was less $$ than buying it by the foot the amount I needed.

 

[1967marti]

If you go and buy a plug/outlet from the store you will see that the 'classic' plug for welders says 30/50 amp.
I think what the tech was trying to tell you was that if your welder has a bad day or you max it out and run it for hours the internals will shut it off rather than pulling until it trips a 50 amp plug.
In my shop I have a 60 amp receptacle that I plug my mig/tig into... Is it safe...maybe.... In the perfect world your wire would be over-rated for your breaker and the breaker would be matched to the device you were using on that circuit.

 

[Norcal]

If you go and buy a plug/outlet from the store you will see that the 'classic' plug for welders says 30/50 amp.I think what the tech was trying to tell you was that if your welder has a bad day or you max it out and run it for hours the internals will shut it off rather than pulling until it trips a 50 amp plug.
In my shop I have a 60 amp receptacle that I plug my mig/tig into... Is it safe...maybe.... In the perfect world your wire would be over-rated for your breaker and the breaker would be matched to the device you were using on that circuit.

The attachment plug you are writing about is a 3-wire 125/250V (Non-grounding) for dryers (30A), & ranges (50A), they are shipped w/ 2 neutral prongs, 1, "L" shaped for 30A, & a 2nd flat one for 50A, they are not intended for welders.

 

[Charliekilo]

I think this is what he is talking about.
http://www.electricsuppliesonline.com/leviton-931.html