Question

what is the difference b/n three phase 220 and three phase 380

Answer 1

I am thinking that amplitude isn't all that you are looking for. 208 three phase, and 480 three phase are pretty common in these parts, again amplitude is the primary difference, all other procedures are similar, like delta-delta, delta-wye etc.

Answer 2

220 Volts, 3 Phase
1. If you have 220 volts and 3 phase power available, the kiln will come with a 3-wire powerblock for the 3 hot wires that give the 3 phase.
2. Between each hot wire, 220 volts can be measured.
3. There is no need for a neutral wire to come to the kiln in this case, just an earth ground wire in addition to the 3 hot wires.

380/220 Volts, 3 Phase
1. If you have 380/220 volts and 3 phase power (like a lot of foreign countries), the kiln will come with a 4-wire powerblock for the 3 hot wires that give 3 phase and one neutral wire.
2. Between each hot wire, 380 volts can be measured.
3. Between the neutral and any of the hot wires, 220 volts can be measured.
4. The kiln circuits are connected to the neutral line and one of the hot lines for each kiln section to provide 220 volts for each kiln section.
5. In addition to the 3 hot wires and the neutral wire, an earth ground wire is needed as well.