#8 conductor overcurrent protection

[wkl_duff]

I am working on a house rewire where previous electrician abandoned the job partially completed. He ran a circuit for a welding outlet through 3/4 EMT using #8 conductors. OCP is 60 amp breaker at main pannel and 60 amp at 6 space box. Using table 310.16 shows this not to be allowed, is there an exception or another article that allows this situation.

 

[iwire]

Re: #8 conductor overcurrent protection

The rules for welders are different.

Take a look at 240.4(G) and most of Article 630.

 

[RUWired]

Re: #8 conductor overcurrent protection

wkl duf,
My 225amp welder would'nt work with that breaker.
primary amps: 47.5 20% duty cycle. multiplier 0.45. minimum wire size = 21.37. maximum brkr= 40 amp (21.375x 200%=42.75)However if it was a 40 % duty cycle it would work.47.5 x 0.63=29.92,minimum wire size.Maximun brkr= 29.92x200%=59.85(60) if allowed to round up?The circuit you have would need a pretty stout welder to hold up to a 60amp breaker.
Rick