10 or 12 guage
In the us the "nominal" voltages are 120/240. Nominal means "the name we use" The actual voltage vaires alittle. I believe you are telling us the the nominal voltages are 110/220 where you live.
If the 220v appliance uses a neutral (stoves, and cloths dryers most often do) then you would run a 3 conductor cable plus ground. If the appliance does not need a neutral (water heaters usually do not) then you would run a two conductor cable plus ground. At the panel you will connect the two hot wires from the cable to a two pole breaker. Each pole is 110 to neutral, and they are 220 phase to phase.
Check the amperage of your water heaters, and dryer. Most of the ones where I live are 30 amps. If you are wiring to US standards you will need number 10 wire for those.
Also if you wire to US standards, you cannot run from the switch to the light using number 14 wire, if the fuse or breaker is 20 amps. If you have any 14 guage wire on the circuit it must be on a 15 amp breaker.
There is an exception for fixture wires, but people often get confused. Fixture wires do not leave the fixture box via the house wiring. That exception is for when a ceiling light, for example is hung from a chain, or for the wires to a fixture that do not leave the ceiling box at all.
The wires from the wall switch up to the ceiling box (or other wall box) must be the same full size as the rest of the circuit wires. (meaning not larger than the rating of the fuse or breaker allows.