welder - 30 amp, wire sizing ?

[Stevenfyeager]

I do not wire for welders very often. The nameplate says PRI: 208v -33 amps or 240v - 30 amps. Should I go higher than #10 for the 240 volts ? I do not know yet if 208 is available at the jobsite. Thank you.

 

[Hv&Lv]

That 30 amps is all the welder will pull. I don’t know anyone that welds at the highest setting, unless their torch is out of gas and they are burning something off

30 amps, I also bet the duty cycle is less than 30%, so continuous isn’t a factor.

 

[Besoeker3]

I'd probably go for 6mm^2................

 

[Hv&Lv]

I'd probably go for 6mm^2................

Here we go...

 

[LarryFine]

I'd probably go for 6mm^2................

We don't use metric amps here.

 

[tom baker]

The ampacity of the branch circuit is dependent on the duty cycle. A little buzz box is 20% duty cycle meaning it can weld 2 minutes out of 10.
Start with section 630.11. Its pretty easy to figure out your OCPD and wire size.

 

[Stevenfyeager]

The ampacity of the branch circuit is dependent on the duty cycle. A little buzz box is 20% duty cycle meaning it can weld 2 minutes out of 10.
Start with section 630.11. Its pretty easy to figure out your OCPD and wire size.

Thanks, but I don't know about these. The nameplate says duty 60 %, and SEC. amperage - 200. What does the 200 mean ? One hour rating.

 

[tom baker]

Please start with 630.11, have a copy of welder name plate, take notes, see how you do.

 

[Another C10]

I do not wire for welders very often. The nameplate says PRI: 208v -33 amps or 240v - 30 amps. Should I go higher than #10 for the 240 volts ? I do not know yet if 208 is available at the jobsite. Thank you.

Without getting all technical, it seems the calculated load on the nameplate is 30 -33 Amps so #10 wont work, it'll be maxed, so then you'll want to size up to a #8 maybe even go higher to a #6. If its a long distance say 100 - 200 ft then I'd go with the #6.

 

[Besoeker3]

We don't use metric amps here.

Nobody does. But I bet your Amp is the same as our Amp.............

 

[retirede]

Nobody does. But I bet your Amp is the same as our Amp.............

Fender vs Marshall?

Couldn’t resist.

 

[kwired]

Thanks, but I don't know about these. The nameplate says duty 60 %, and SEC. amperage - 200. What does the 200 mean ? One hour rating.

Probably secondary amps, at something less than 50V.

Does the welder have a 50 amp cord cap already installed on it? If so run at least a 40 amp circuit to the receptacle.

 

[Besoeker3]

Fender vs Marshall?

Couldn’t resist.

Very good! I played acoustic so had no Amp.

 

[topgone]

Thanks, but I don't know about these. The nameplate says duty 60 %, and SEC. amperage - 200. What does the 200 mean ? One hour rating.

With a welder duty of 60% and a secondary amp of 200A, think of it as an on-off operation; 6 minutes welding time then a period of 4 minutes rest time! So, your average secondary current will be 200 X sqrt(0.6) = 155 A! Say your welding voltage is 25V, the current at the 208V primary would be = 155X (25/208) = 18A! For welding units, the OCPD should be 200 or less! So, 18 X 2 = 36A! You can use 30A breaker for that install!
Hope that helps.

 

[Another C10]

With a welder duty of 60% and a secondary amp of 200A, think of it as an on-off operation; 6 minutes welding time then a period of 4 minutes rest time! So, your average secondary current will be 200 X sqrt(0.6) = 155 A! Say your welding voltage is 25V, the current at the 208V primary would be = 155X (25/208) = 18A! For welding units, the OCPD should be 200 or less! So, 18 X 2 = 36A! You can use 30A breaker for that install!
Hope that helps.

That sounds much more convincing than my answer.

It's always good to be humbled now and again ..

 

[Stevenfyeager]

Thanks for the advice, but I've got a wide spread of answers. I am still wondering if I should go larger than #10, its probably 100 feet.

 

[Another C10]

Thanks for the advice, but I've got a wide spread of answers. I am still wondering if I should go larger than #10, its probably 100 feet.

Personally I would go larger than #10 just because it seems the equipment mentions the amperage range between 30 - 33 A. You could search the product to get better specifics. There are many variables which you have read and I'm sure there all justifiable, point is though the nature of the welder may not be such a complex process to where just keeping it simple is probably the most feasible. Worse case scenario you put an amp probe on it during operation to confirm your wiring and thermal protection is appropriate, I know a little risky but you can always change it if necessary and take the hit on time and supplies, just call the manufacturer and ask them what is the required circuit protection, I'd say 40 Amp Breaker # 6 just in case you need to bump the breaker to a 60A worse case scenario you put a 30A on a #6 wire... look at it as future growth, or turn the 60 amp into a sub panel, either way there are always legitimate safe solutions, just get the customer their system, safely and legally of course. Just a thought.