I also have the miller 115VAC spot welder, and its on a 20 or maybe a
15 amp circuit and tripping the breaker has never been a problem even
with a lot of continous use..

Just make sure your contact points line up over each other and the
diameter of the tips is within spec or it will not produce good sound
weld. Also make sure your threads on the tips to tongs are clean and
tight, and it don't hurt to apply a conductive anti sieze
either.........

To me adjusting the toggle action is a pain in the butt, and I usually
leave one of the nuts sufficiently loose so no wrenches are needed, so
its a simple matter to adjust one or the other and just snug em hand
tight.
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