two roll mill voltage 380 50hz. What is the difference between 220 volts, 3 phase and 380 ... 380/220 volts, 3 phase. If you have 380/220 volts and 3 phase power (like a lot of foreign countries), the kiln will come with a 4wire powerblock for the 3 hot wires that give 3 phase and one neutral wire. Between each hot wire, 380 volts can be measured.