+18 Landscape Lighting Wire Size References. The greater the distance between the transformer and its power supply, the more resistance arises in the circuit, causing the voltage to fall. 10 awg is commonly used in the main lines, while 12 awg is placed between the lights.
Bigger projects might call for 10/2 wire to be used. The longer the length, the thicker the wire will need to be. The further you get from the transformer and its power supply, the more resistance occurs in the circuit which causes the voltage to decrease.
