Check the "Nameplate" label on your welder; it will have at least two ratings listed on it. The "INPUT " voltage should be 220/230 VAC, and there will be an Amperage listed. Then there will be an "OUTPUT " amerage listed at some percent duty cycle; this will be the load available at the welding electrode for that percent of the operating cycle, and may be either an AC, or a DC voltage.

For purposes of determining the size of branch circuit breaker to feed your welder, you are interested in the "INPUT " values. If that is more than 50 or 60Amps at 220/230Volts, then you will need to upgrade your shop main service; you might want to consider doing that, at any rate, just to be on the safe side. You should also connect an "ISOLATING TRANSFORMER " in the circuit that feeds the welder; this will help reduce any interference that the welder will induce in other circuits that are conected to the same transformer that serves the property from the electric company's power pole. Your power company may also require that you have a separate service and transformer to serve a welder that large, just to eliminate this sort of problem. As to the flickering of the lights in the house, this is a normal occurence when a welder is connected to the same service; however, if the lights dim and stay dim as long as the rod is lit, then the transformer serving your house or shop is too small, and the power company should be contacted for advice.

I think you should contact a qualified licensed Electrical Contractor, or a Master Electrician, for the safety of all concerned.

My credentials: Master Electrician, Licensed Electrical Contractor, and 40 year Lineman/Construction Electrician/Millwright (RETIRED).