Welder instructions

[steve66]

The instructions for a Miller XMT 304 welder list a 200 amp circuit breaker as the maximum input circuit breaker. But then they list #2 wire as the minimum input wire size.

So is #2 wire on a 200 amp breaker legit for the input to a welder??

Steve

 

[acrwc10]

Inrush current, look in art. 630.11

 

[acrwc10]

Woops, 630.12

 

[juptonstone]

max breaker sizefor welder...

max breaker sizefor welder...

Think of it like air conditioning... in AC the maximum ampacity for a disconnect is 125% of the circuit ampacity, or the next breaker size up... typically listed on the nameplate. Same sort of thing with the welder... Wire size is what the what the welder draws. Breaker size is what the possible startup ampreage is.

 

[iwire]

It is not really about inrush. It is about duty cycle, and the fact that before you will overheat the circuit conductors you will overheat the machine.

 

[steve66]

Now I see. So the Breaker size can be up to twice the ampacity of the conductors.

Thanks:
Steve