I just bought a Arc Welder that can use 220 or 115 but since the only 220v outlet is the dryer inside the house I had to choose the 115v mode. I have it plugged in inside the garage on a 20 amp breaker. The manual said no to go above 70v on a 30 amp breaker. The job I need requires all 70v and when I get going for a few minutes welding the breaker trips.

Would upgrading the breaker to 30amp keep the breaker from tripping, or would installing a 220v outlet without destroying the walls and stuff work better?

I would prefer 220v but I don't want to destroy the walls. The breaker panel is in the garage also.

Increasing the breaker to 30 amps is NOT an option.

Run it within the guidelines at 120v, or install a 240v circuit for it.

Switcher,

What Stan is telling you is that the size of the conductors govern the amount of ampcity of the conductor.

NEC code provides these rules:

The current running through a conductor is limited to 15 Amps for #14 AWG cable. A #12 gauge is used for 20 Amps and a #10 AWG gage is for 30 Amp conductors.

If you try to run 30 amp through at listed 20 amp conductor, you may start melting the insulation on the conductors or cause a fire.

Pulling the cable, should not be all that difficult. You remove the receptacle on the outlet area. At the main panel, cut power off, then find the end of the run that breakers to the room. Connect the new cable and use the old wire to pull the new right through to the panel box.

PLEASE, if you believe that no do not that the experienced enough to do this you need to get a qualified electrician in to do the work.

Since the current level of voltage in household is either 120 or 240, not 110 or 220. Since you are going to have to run new conductors for your welder, you might as well use #10 AWG with 240 volts and a new 240 VAC outlet.

The higher voltage will help the welder operate better.