Understanding Wire Gauges
Wire sizes are listed in terms of gauge. The lower the gauge number, the thicker the cable. For example, battery cables are much larger in size and can be 4ga. to 2ga. or even larger. When working on your vehicle you will generally find wire gauges from 18 gauge (thin) to 10 gauge (thick). The more amps a wire needs to carry, the thicker it must be. Also, you will need thicker wires when the length is extended. The longer the cable has to be, the greater the resistance. Long cables can lead to voltage drop. To make up for this you can go up one size such as from an 18 gauge cable to a thicker 16 gauge cable.