the wiring of the new 220v in a house for like stoves and apliance changed from the old 3 wire to 4 wire for a power interrupt or GFI for electricions safty to make sure the power if off when breakers are shut down. How 220v works with 4 wires: (one wire to each)
1 Black wire carries 110v
1 Red wire carries 110v
1 White wire acts as a common
1 Green wire acts as a ground