Stranded copper is the wire of choice for many projects when building custom wire harnesses or adding accessories. 20AWG - Used for low voltage sensors, indicator lights, instrument panel or dash lighting. 14AWG - Most popular when fabricating harnesses for general use including lighting of headlights, taillights and brake lights, ignition systems and interior accessories such as radios, interior fans and gauge panels. 12AWG - Wire can be used to supply power to ignition boxes, cooling fans, fuel pumps and other higher amperage accessories including power to electric trailer brakes. 10AWG - Commonly used for higher amperage applications including alternator charging wire and supplying power to trailer for interior lighting or charging trailer batteries when utilizing tow vehicle charging system.