A line voltage thermostat for 240 volt control should be a two pole device. Code states that both of the "hot" wires must be broken when shutting the load off. By just shutting one leg off, the load device still has a 120 volt potential to ground through the unswitched leg. This is an unsafe condition. If any work has to be done on the load device and with the thermostat seen to be in the off position, a presumption is made that there is no voltage at the device. Best scenario turn the breaker off when working on any 240 circuits, don't depend on disconnecting devices within the circuit.
It could if you don't get the terminals and motor wires on the correct terminals.
Wire is wire - is doesn't matter what voltage you use. However, if you are changing the voltage on a device from 240 to 120, given the same power requirement, you may need bigger wires for the doubled current (and increased heat of resistivity).
It depends on the voltage, but if you are using it on a 240 v system, it's quite OK to use wire that can take 600 v (if you had to buy the wire, you would be spending too much).
yes
4 copper
Yes 220 & 240 are considered the same.
Yes <<>> In North America, a three wire 120/240 volt system uses a neutral wire. For 240 volts two "hot" wires are used with no neutral.
no
It could if you don't get the terminals and motor wires on the correct terminals.
no
Wire is wire - is doesn't matter what voltage you use. However, if you are changing the voltage on a device from 240 to 120, given the same power requirement, you may need bigger wires for the doubled current (and increased heat of resistivity).
It depends on the voltage, but if you are using it on a 240 v system, it's quite OK to use wire that can take 600 v (if you had to buy the wire, you would be spending too much).
yes
4 copper
You can't. The 120 volt GFCI is probably just a 2-wire (hot, neutral and ground) You would have to run a new 3-wire (2 hots, neutral and ground). The two hots are how you get the 240 volts (120+120=240). Also you must make sure the wire is gauged properly. #10 wire for 30 amps, #12 wire for 20 amps, etc.
Use the 4 wire if possible. You would only use a 3 wire for an old appliance.You shouldn't if possible. The 3 wire has no neutral wire as the 4 wire does. Som applications require the use of a 3 wire and some don't.
In residential wiring, if it is used as a switch leg or in 3 wire 240 volt circuits.