I have a LG-30A Plasma Cutter and the on & off breaker switch trips constantly. The voltage required to cut seems to exceed the breaker. The breaker indicates that it is good for up to 400V but I think it is tripping a lot sooner. Is there an adjustment in the cutter or is there a replacement breaker that can be installed?

Clean acurate cutting is impossible at this point.....Help.

What breaker is tripping? Are you talking about the AC mains breaker? That form of breaker works on current (actually a bimetalic contact that uses heat from the current passing through to trip) and the voltage rating is just a max value. If you are using 230VAC or 120VAC then its within the rating. What is tripping the breaker is that it is overloaded. Plasma is a constant current process meaning that the plasma unit tries to maintain the cut current as set on the unit letting the tip volts (typically 100 to 150 VDC) vary with the gap distance.

You might want to move this over to the Plasma cutting forum on this list. You will probabaly get more answers there.