Wire is not sized by voltage. It is sized by current measured in amps.
Some common copper wire sizes and their current capacities are:
15 amps -- 14 gauge wire
20 amps -- 12 gauge wire
30 amps -- 10 gauge wire
40 amps -- 8 gauge wire
Relative to Earth, the voltage might be approximately: Earth 0, neutral 3 v, live 217 v.
What would be the max. length a 30 amp service could be run
To calculate the wire size, a system voltage is needed.
To answer this question the voltage and load amperage is needed.
Wire size is based of the amperage of the device. To answer this question the amperage is needed or the wattage and voltage of the device.
A #14 wire will do fine for grounding a 20 amp device. That is the size of the ground wire in a 2 conductor # 12 wire building cable.
The wattage of the water tank is needed to size the breaker and the wire to feed the tank.
# 6 wire
Check the internet for a voltage drop calculator.
To calculate the wire size, a system voltage is needed.
To answer this question the voltage and load amperage is needed.
AWG 16
Wire size is based of the amperage of the device. To answer this question the amperage is needed or the wattage and voltage of the device.
A #14 wire will do fine for grounding a 20 amp device. That is the size of the ground wire in a 2 conductor # 12 wire building cable.
The wire size depends on how much current it will conduct.
Wire size is calculated from the amount of current the load draws. More information is needed. Voltage and amperage will do fine.
The wattage of the water tank is needed to size the breaker and the wire to feed the tank.
AWG # 10 wire on 30 amp circuit.
In a floor lamp or table lamp a #16 wire is what you need.