Electric Welders and Service Calculations.
- Thread starter Russell39
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I tried to edit but what I meant to say was the Welders Rated Primary Current, or the Welder(s) amperage after the applicable Duty Cycle factor value derived from Table 630.11(A).
JoeStillman
Senior Member
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- West Chester, PA
630.11(B) gives more diversity factors for three or more welders. It's 100% for the two largest, 85% for the third largest, 70% for the fourth largest and 60% for all the rest. These diversities apply to the duty-cycle currents from table 630.11(A).
I have used 630.11(B) for sizing a feeder to multiple welders, but wanted to be clear on if those demand factors would also apply if I was performing an overall standard service calculation for a building that had several welders in addition to the other usual loads such as lighting, A/C, heat, receptacles etc. I am about to test for another Masters license, and have been running various load/equipment scenarios involving standard service calculations. I usually have no problem with any of artice 220, but occasionally run across a particular piece of equipment that makes me think about where and how it fits into the standard service calculation.
So, it seems clearer now that I can use 630.11(B) if calculating several welders on a standard service calculation...no different than the way we are allowed demand factors to be applied to multiple ranges, dryers, kitchen equipment, etc. Just wanted an opinion on if 630.11(B) would actually apply to the standard service calculation.
Thanks Joe, appreciate it.
Robert
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