Wire Gauge & Fuse Calculator
Undersized power wire restricts current and leads to performance-robbing voltage drop, while incorrect fuse sizing risks severe electrical failure. Use this calculator to determine the safe wire gauge, maximum recommended fuse size, and voltage drop for your system's power run.
System Inputs
Recommended Wire Gauge
4 AWG
OFC (Oxygen-Free Copper)
Recommended Main Fuse
100Amps
ANL style
Total System Current Draw
96.6Amps
RMS ÷ (V × efficiency)
Estimated Voltage Drop
0.821Volts
Elevated — consider shorter run / larger gauge
Safety & Educational Notes
Fuse Protects the Wire, Not the Amp
The main inline fuse near the battery is designed to prevent the car from catching fire if the main power cable shorts to the chassis — not to protect the amplifier's internal circuitry. Size the fuse to the wire's ampacity, and place it within 45 cm of the battery positive terminal.
OFC vs. CCA
Copper-Clad Aluminum (CCA) has significantly higher resistance than Oxygen-Free Copper (OFC) — roughly 1.6× per metre — and it oxidizes faster, especially at termination points. To handle the same current safely, CCA requires a thicker wire (one gauge size larger). For any high-current or permanent install, OFC is the safer, more reliable choice.
The Big 3 Upgrade
If your calculated current draw exceeds 120+ Amps, upgrading the vehicle's factory alternator-to-battery positive, battery-to-chassis ground, and engine-block-to-chassis ground wires (the "Big 3") with 1/0 AWG OFC is strongly recommended. This lowers charging-system resistance so the alternator can actually deliver the current your amplifiers are asking for.