Greetings. I've done quite a bit of 110 wiring and some 220 but I'm a bit weak in that area. I've got a new 60 gallon 220V air compressor that is now located in my garage approximately 50 feet from the house which is where the main breaker panel is located. There is no room to add another 220 breaker or in any way add an additional separate circuit without adding a sub panel. I've purchased a two pole 30 amp breaker and matching sub panel and need to wire it into the existing main breaker panel. Most 220 circuits I've seen previously are either 3 or 4 wire configurations however the motor for my compressor is a 2 wire plus a ground setup. I've run the appropriate length of 10/2 outdoor NM wire from the compressor to the location where the sub panel will be installed. What I need to know is the connections that need to be made. There was previously a hot tub 220 circuit but it was removed when the hot tub was relocated to my sisters house however on each leg coming in from the meter there is a copper lug with a set screw that look to have been added and are not used by any other circuit. I think possibly this is where the hot tub wiring was connected but am by no means certain. What I really need to know is, since I need 220 but will have no third wire for a neutral, and I know this is how it needs to be and have read a good deal about this type of connection but can find no schematics or specific connection instructions, do I simply hook one wire from each incoming leg to each of the breaker connectors in the sub panel, and then do the same on the opposite side of the breaker using the wiring that runs out to the compressor, and just not use a neutral at all, and connect my bare ground wire to the neutral bus in the main breaker panel? Any help, additional information or diagrams will be appreciated. Comments to the effect that you can't run 220 without at least 3 wires plus a ground wire, will not, as I already know that's untrue.Here's what I'm assuming I need to do. Please feel free to correct any incorrect assumptions if I'm wrong. Thanks.
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