Electrical

The electrical section holds what it takes to wire a car or add to its wiring. It covers cable, terminals and connectors, sleeving and grommets, and relays, fuses and circuit breakers. Switches and push buttons, warning lights, battery boxes, relocation brackets, cut-off switches and ignition coils complete it.

Most parts are listed by size, so match them to each other:

• Cable is listed by cross-section and colour, from 2.5 mm² for small loads to 10 or 25 mm² for battery leads. Cable that is too thin for its current runs hot and drops voltage.
• Terminals are listed by type and size: push-on terminals by blade width (4 or 6.3 mm), ring and fork terminals by stud size (M3 to M10), and sealed connectors by the number of pins. The colour of an insulated terminal shows the cable size it takes.
• Sleeving and loom tubing are listed by diameter and length, in polyester or polyolefin.
• Switches and warning lights are listed for 12 V, with the colour of the lens or LED.

Protect every new circuit with a fuse near the power source, rated for the cable rather than the device. Heavy loads such as fans and fuel pumps should run through a relay, so the switch on the dash only carries the relay’s small current. A battery moved into the cabin or boot needs a sealed box, and its cable needs a grommet wherever it passes through a panel. Most competition rules also ask for a master switch that cuts the battery and the engine, reachable from outside the car.