Wire Gauge Selection for Race Harnesses
Race harness design balances voltage drop, ampacity, weight, heat dissipation, and bundle density. Oversizing increases weight; undersizing increases heat and drop. See our electrical systems in motorsport for the full design guide.
Voltage drop vs ampacity
Proper conductor selection must satisfy two constraints: voltage drop (conductor large enough to keep drop within target) and ampacity (conductor safely carries current without overheating). Use the AWG sizing calculator for voltage drop sizing; always verify ampacity separately.
Motorsport considerations
Elevated ambient temperatures reduce ampacity. Bundled conductors require derating. Thin-wall SAE J1128 wire is common; proper derating is critical inside engine bays. Size for 3% drop on critical circuits and consider future load expansion.
Integration with other tools
After sizing wire, verify calculate voltage drop and fuse sizing calculator. For battery loads, check battery runtime calculator.