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zxcvbob

wrote:
On Thu, 27 Jul 2006 19:48:20 -0000, (Chris
Lewis) wrote:

I perhaps wouldn't have been quite so confused if he hadn't said 100A -
it sounded more like the output current of a small welder

I agree. It had me scratching my head and I looked up the PDF on the
Lincoln site. Sure enough that is what it says, along with "per the
NEC" so I looked up the welder rules in 630.
Until I ran the numbers I had a hard time getting my head around it
too but that is what it says..

My opinion: It doesn't actually /need/ a 100A breaker; a 60A or 70A
will work just fine. But if you stick the electrode while doing
shielded metal arc welding (stick welding) at the machine's maximum
current setting you can pop the breaker. So the electric code lets you
oversize it. Lincoln and Hobart and Miller don't care how much the
breaker costs, they just recommend the size that give the least trouble
regardless of what you try to weld. If your technique is good and you
only operate the welder at half-power or less, you can probably get by
just fine with a 30A breaker. You'll still need 10 gauge wire because
the maximum duty cycle is probably close to 100% by the time you get
down to 30A input current.

Best regards,
Bob