Welder Outlet Rating?

[davelectric]

I am installing outlets for a 460 3 phase welder 37 amp 60% duty cycle.
Per 630.11A .78 x 37 = 28.86 amps calculated load
Conductor would be sized #10 per 310.16
Overcurrent protection would be 60 amp breaker max
My question is would I use 30 amp outlets sized to the branch circuit wiring (was planning on using the Meltric with the built in disconnect.)
Spoke to the welder manufacturer tech support and they recommended 60 amp recpt.

 

[david luchini]

I am installing outlets for a 460 3 phase welder 37 amp 60% duty cycle.
Per 630.11A .78 x 37 = 28.86 amps calculated load
Conductor would be sized #10 per 310.16
Overcurrent protection would be 60 amp breaker max
My question is would I use 30 amp outlets sized to the branch circuit wiring (was planning on using the Meltric with the built in disconnect.)
Spoke to the welder manufacturer tech support and they recommended 60 amp recpt.

Per 210.21(B)(1) Ex. No. 2, a receptacle for a cord and plug connected arc welder shall be permitted to have a rating not less than the minimum branch circuit conductor ampacity determined by 630.11(A).

So, by code, a 30A receptacle should be fine for your 28.86 Amps calculated per 630.11A.

 

[LHarrington]

I always thought the duty cycle played a role in the the circuit sizing formula? for example .78 * 37 * .60 = 17.31amps. We use 30amp recpts here all day long.

LHarriington

 

[david luchini]

I always thought the duty cycle played a role in the the circuit sizing formula? for example .78 * 37 * .60 = 17.31amps.

I don't think that the duty cycle gets multiplied into the ampacity. Per 630.11(A), the minimum ampacity should be the rated current times the multiplication factors based on duty cycle shown in table 630.11(A).

So a single arc welder with a 37A rated primary current and a duty cycle of 60% would have a multiplier (nonmotor generator) of 0.78 based on the 60% duty cycle. 37A x 0.78 = 28.86 minimum ampacity for the supply conductors.

 

[BJ Conner]

Is it UL Listed>

Is it UL Listed>

"I Spoke to the welder manufacturer tech support and they recommended 60 amp recpt."
What does the manual or any drawing for the machine say? Is there a name plate that says 60 amps?
If the answer to any of the above is yes then I would say use the 60 amp plug. If it got UL listed with a 60 amp feed I wouldn't change it.