On any 220v circuit you only have to switch one wire. Each hot lead wire acts as the neutral for the other so if you interrupt one then there is no circuit. Most of the cables for power tools only have the two hot leads and a bare ground. You only need the third conductor (neutral i.e.) if you need to also run some 120 volt functions like the clock and lights on an electric stove. I run my air compressor by switching just one wire through the pressure switch.
Just as an after thought, I also hooked up my 220v DC that way. I wanted to be able to turn it on from either end of my shop so I used a pair of 3 way light switches to turn it off and on, only switching one of the two hot leads.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.
Last edited by Cherryville Chuck; 06-08-2016 at 12:37 AM.