Hello. I have an older stick welder that has a ground, white wire and black wire. The outlet I have to connect to has a ground, black, white and red wire. Is there a way I can connect the old welder to the newer wires? I know the red and black are hot but what about the common white wire? What should I do? Thanks.

Sounds like your welder uses a straight 240 VAC.

In theory, you do not need a neutral. If you have 240 VAC between the Black and Red, then you can cap off the White, neutral return. You would connect Black to black and Ewd to White. Please take a perment marker ot=r black or red tape and put a band around the white lead on the welder to flag the conductor as a hot conductor.

Your welder was wired for a straight 240 drop which originally accomplished with just the black and white wires.

What about the amperage??

What is this receptacle you have for?

Thanks for the help. I'll give it a try soon and post the results. I used to be good at wiring but if you don't use it you loose it... :) The fuse panel is old and has a small rectangular panel that you pull out and insert 2 230 volt 50 amp fuses. To turn the power off you flip the small panel upside down. It is in my garage and the person before me wired it. I have not checked the wires for voltage yet. I'm just trying to figure out how to hook it all together... I think it was used for a newer welder or air compressor.

Welder or air compressor? BIG difference.

What size is the wire going to the receptacle.

Not sure the actual gauge but the copper is close to the same size of a 1/8 drillbit. What gauge should be run with a welder?

1/8" sounds WAY small for the required 50A circuit you need.
You are going to need #6CU NM cable for this circuit. That is more like 1/4" in diameter.

Before any of my fellow code gurus jump on me I know you can wire a welder with smaller wire. I just feel this is not wiring a welder, it is wiring a 50A receptacle. Who knows what will be plugged in there down the road? Maybe a 40A kiln?

If I have to change the wire it's no big deal. I just don't want to be welding and set my wall on fire... from the inside... The garage is from the 70's and I'll probably be the last person using it so I'm not too worried about who will be using it in the future.