White.
The ground wire in a two or three conductor #12 cable is a #14 bare ground wire.
A #4 copper conductor will limit the voltage drop to 3% or less when supplying 20 amps for a distance of 250 feet at 120 volts.
No !
If you combine two 110 volt power lines it does not give you 220 volts, the voltage will be the same. The only way to turn 110 volts into 220 volts is with a step-up transformer.
A breaker is based on wire size, as the breaker protects the wire and not the load. This is a voltage drop question. A #3 copper conductor will limit the voltage drop to 3% or less when supplying 60 amps for 110 feet on a 110 volt system.
White.
The ground wire in a two or three conductor #12 cable is a #14 bare ground wire.
A #4 copper conductor will limit the voltage drop to 3% or less when supplying 20 amps for a distance of 250 feet at 120 volts.
If it is a 110 volt light it can safely run on a 20 amp circuit with AWG # 12 wire.
Because of voltage drop, 4 awg copper would be recommended for that distance run. <<>> A #1 copper conductor will limit the voltage drop to 3% or less when supplying 50 amps for 200 feet on a 110 volt system.
A #1 copper conductor will limit the voltage drop to 3% when supplying 15 amps for 700 feet on a 120 volt system.
No !
Presuming that you would like the least expensive installation, the following is calculated on overhead aluminum wire. The wire size needed to hold the voltage drop to 3% would be 3/0 MCM. If the installation could be run on 240 volts then the wire size can be reduced to #2.
110 feet x 110 feet = 12,100 square feet (this, incidentally, is a very large room).
If you combine two 110 volt power lines it does not give you 220 volts, the voltage will be the same. The only way to turn 110 volts into 220 volts is with a step-up transformer.
You will need to look up cabling/wiring codes.Is it:Telephony,Audio distribution,110 volt power lines, orHigher voltage power lines?