I have a similar situation in my garage. 240V 5hp compressor, 240V 180A welder, 240V 50A plasma cutter and 240V 5000 W heater. Wired up a receptacle near the back and the front of the garage. Made an adaptor plug so the welder and plasma can plug into the front receptacle. Also purchased a 25 ft 50 Amp welding extension cord so I can weld in the driveway.
Hint: Stove or Range cords are cheap to buy and have large 10 or 8 gage (IIRC) 3 or 4 wire - Home Depot also carries the appropriate receptacles and plugs, so you can make your own cord ends and boxes and adaptor cables.
The breaker information presented here is accurate - the risk of overfusing a machine is not a terrific idea, mine is set on a dual 30A and 15A breaker, so I cannot use more than one 240V tool at a time. Not ideal, but it works.
I rewired the 8g run to the garage in the main panel to give me 240V out of the 100 year old panel that is in there. Going to either update or replace the entire affair shortly, as with the heaters, shop vac, router and the dozen light fixtures I'm running out of juice during motor start up. Will be fusing the circuits with the appropriate sized breakers whenever the time comes - currently underfused which is fine and has worked correctly for 10 years.
Last edited by tulowd; 02-25-2019 at 08:24 AM.