I have a an old 230 volt S.D.LEE arc welder (that I can not find any info about) printed on the front is says "PRI volts 230 max OCV 78 arc volts 25 PRI amps 65.7 SEC amps 230 temp rise 115c 60 cycles single phase model 110-085"
I am not sure what that means but I think it means at the welders max setting I need 230 volts at 65.7 amps?
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I rent an old house that looks like its haunted it has an old square D panel 125 amp QO combination panel (also don't know what that means really) lots of empty slots but the combined amps not including the main shut off is 165 amps I think I need a 70 amp breaker for the welder (not sure).
Can I safely add one? If so, what conduit should I use with the 70 amp breaker to run my welder about 45 feet from the panel?
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I really don't want to burn the house down, my landlord probably wouldn't like that either.
Best Answer
While the panel is rated 125 amp, you have a 100 amp service. You also have an electric dryer and water heater in addition to the usual lights and outlets. Adding a 66 amp load to all of this is definitely overloading the service.
If you went ahead and installed this welder, you won't burn down the house (at least not from electrical loads, from welding is another story) but you would get nuisance tripping. Every time you struck an arc, the lights would dim. The resulting voltage drop could damage electronic equipment such as computers and TVs, as well as anything else with electronics, which is virtually everything these days.