Wiring up my 250ex

[A/C Guy]

so you only use 3 wires on the welder?? the 2 hots and ground? I was told I used to have to run 3 wires for 220, 2 hots and the netural, then ground to the box/conduit. The guy at the store said that a lot of places are making it 4 wires, 2 hots 1 neutral and 1 ground wire.

So my plan was to to use 2 hots and the neutral and then wire to green wire to the box. Sounds like there is no need for the white wire(neutral) on on the pt250ex as along as the neutral and ground are bonded at the box. If that is the case then couldnt I hook up the green wire to the withe neutral wire from the box?

First, NEVER, NEVER, connect ground to neutral at an appliance. Never use neutral for ground and never use ground for neutral. The only time you need a neutral is when you need 110. 110 is either leg connected to neutral. 220 is one 110 leg connected to the other. Driers and stoves use the neutral for clocks, timers, control pads, etc. The 220 is for the heating elements. The welder only uses 220 and ground.

Edit to add: Read the first post. The red wire on your welder is NOT for residential use. It is only for 3 phase power. The Black and White on your cord are for your 110 volt legs; green is always ground.

Machine BLACK to wall BLACK
Machine WHITE to wall RED
Machine GREEN to wall BARE (GREEN)
Machine RED and wall WHITE are not used.