By following the National Electrical code recommendations. If you do not understand the principles involved, contact a qualified electrician.
You need to know the amperage to size the wire. For 220 V at 20 A you would need 12 AWG. At 220 V at 30 A 10 AWG.
Yes 220 & 240 are considered the same.
Buy a 3 wire cord for your dryer.
Just replace the cord. Your manual has instructions.
Three phases, one neutral and a GROUND
Depending on the configuration of the cord cap, the green wire is ground, the white wire is the neutral and red and black wires are the 220 volt source.
The white (or neutral) wire is not involved in a 220 circuit. Using US NEC conventions, red and black in a 120/240 split phase service form the 240 (220) circuit. The neutral (white) wire is only used when you want 120 (110) volts.
No, attempting to do so would be neither legal nor safe.
3 OR 4 . you only need 2 wires for 220, 1 phase is 120v between 2 of them its 220v . you also should have a ground for the third wire ,and the newer stuff requires a neutral or white wire for the 4th wire. hope i helped , D
# 3 gauge
6 AWG
AWG #6