ECN Forum Forums General Topics of the Trade General Discussion Area welding receptacles... how many?

Would you ever put more than one 6-50R on a circuit for convenience sake?

If there was only intention of keeping one such machine, and one worker/hobbiest on the premises, it wouldn't bother me. However, there will be a plasma cutter also, and a good possibility of it being a 2-man shop at least part of the time. I'm trying to avoid overly long cords also. (60x72 building, 30x40 work area).

What would you do in this situation?

I would (and have) put as many welder outlets where convenient for the users.

I would talk to the customer and be up front with them.

I can do it for this lower price and it may trip, or for more money I can separate them and prevent any possibility of a trip.

Also it is worth taking a look at the "Electric Welders" Article in the NEC (630 in 2002). The rules are much different than the normal rules, you may use smaller circuits than you expect depending on the welders duty cycle.

[This message has been edited by iwire (edited 11-17-2006).]

It would also seem to me to be an issue of what you are gluing together.

Around here we have welders with up to 500 amp capacity, and one with a 100% duty cyle at 800 amps. But how often are they turned up that far? Almost never. Only when we air/arc somthing.

So if all you are doing is light duty stuff, this might not be the issue you think it is. Welders are rated for their max output, turn em down and you would be suprised at how little they draw.

TW

Well, do they have two welders now to base anything off of? If not, IMPO I wouldnt worry about the possible future use, unless it was defintate, and the use of the shop was specificaly "welding" or metal fabrication, rather than say an auto shop that did some welding perioricaly. Otherwise you would end up with something the size of a feeder that may be totaly unnessesray. Considering you are basing you assumption off of receptical rating.... If you look at the nameplate rating it may be a different story. Mine has the same 50A receptical, but has a 21A input max @ 30% duty. That said I could have two of the same unit on the same 50A circuit.... The multiplier for a 30 duty cycle is .55 for mine. That shop might not have the same welder... It is the name/data plate that you need to base your decision on.

See 630.11[b](A)]/b] + then (B), and if you look at 630.12, you'll realize the cord cap and breaker for it is already double sized most often.

As the others have said, you can most likely put many outlets on the one circuit. Don't let the 6-50 plug on the welder throw you off.
Case in point. I have a Hobart Handler 180 amp MIG with a NEMA 6-50. It has a 12 guage cord because it only draws 19 amps max. It just came the 6-50 because it is kind of the default plug for welders, not necessarily because of the ampacity needs of the unit.

All good replies.

I'm well versed in Section 42 of our CEC. From what I gather, it pretty much mirrors the intent of the NEC article.

This is an automotive hobbiest customer. (I suffer from the same affliction The welder & plasma machines haven't been spec'ed. I'm basing the realistic maximum on what I've come to know with my own hobby, and dealing with the needs of a few automotive shops.

I've seen many installations with multiple 6-50R's on the same circuit. (machines with primary current in the ~40A range) I just wasn't sure if its considered acceptable practice depending on the situation, or permissable at all.


Good point. Now what do you respond when you get "Well, a professional should know these things" for an answer? This is popular answer for most questions. Sometime I wonder why I continue to do work for this fellow. LOL!


[This message has been edited by u2slow (edited 11-17-2006).]

Do you own a label maker? Right after you get done telling hime the limitations of the circuit, and explaining it the first time - you print up lables to the effect of "This circuit is 50A max, and has multiple locations - to avoid nuisance tripping combined usage must be below 50A." and place that on each cover-plate. You may want to include the panel and breaker number for those days when no one can read until after the fact....