What's the minimum breaker I need for a 110 amp 220v arc welder?

No. that is what the secondary of the transformer can "peak" at. The safest bet is to read the installation instructions, it should give you the circuit requirements but I bet it is in the 20-30a range. What plug is on it?

First off, it is most likely the output amperage that's 110A, not the input amperage. Even if it is the input amperage (which would mean you have a big-ass welder, weighing several hundred pounds) you can still get by on a smaller circuit unless you set it to its highest amperage. If you have a 50A circuit now, use it. If the breaker pops, then you have the choice to turn the welder down (use lower amperage) or put in a larger breaker. I've often wondered if you could put in a few run caps to make the (largely inductive) load look more resistive, which might allow you to get more output.

If this is a little buzzbox, it will run on a 15A circuit easily. If it's at all new, it likely says what the input amperage is on the case, somewhere near the power cable.

GWE

Michael Shaffer wrote:

Here's the auction

I guess that's a buzzbox? Will this be powerful enough to weld two peices of 2.5" diameter exhaust pipe together?

Grant Erw> First off, it is most likely the output amperage that's 110A, not the

50 amp breaker is fine and yes..it will have more than enough power. Too much in fact if you are like me..a novice welder.

Gunner

No 220-pound thug can threaten the well-being or dignity of a 110-pound woman who has two pounds of iron to even things out. Is that evil? Is that wrong? People who object to weapons aren't abolishing violence, they're begging for the rule of brute force, when the biggest, strongest animals among men were always automatically "right". Guns end that, and social democracy is a hollow farce without an armed populace to make it work. - L. Neil Smith

Even though the auction says "230v @ 110a" it's really 110a _output_. For which a 50a breaker is optimum. I run my 225a Lincoln on a 30a breaker 'cause I don't use the higher amps ever (120a occasionally).

The minimum amperage on your welder is 45, which is pretty high for tailpipe. Tailpipe is a very challenging weld even with a lower amperage. Burn through is the problem.

Bob

BTW - I Googled "Buffalo arc welder" and got the toolsteal site. The welder msrp is $65.99, but they have it on sale for $69.30!! Some "sale".

If you are in England that would be 230 volts, 50 Hz. However, if you are in North America, then it is 240 volts, 60 Hz.

The 110 amps will be the secondary current. The primary side current will likely be 1/4 of that or around 30 amps max. If it is a fairly recent welder it should have a capacitor inside to correct the phase angle somewhat, which helps to minimise the current draw at max amps.