I am normally a romex jockey. I am working on a warehouse with a 3 phase service with a delta high leg. Using 2 pole breakers, the previous electrician ran circuits to air compressors using one of the 120 volt legs, and the 208 volt leg. Is this the conventional way to achieve a 208volt single phase circuit, and if so I guess you have to see the manufacturer's instructions on which side to connect the high leg?