Wiring a Car Amplifier: Power, Ground, Remote, Signal
The four wires every amp needs, the gauge you should run, and the fuse placement that keeps your car from catching fire.
A bad wiring job is the single most common cause of system noise, blown fuses, and burnt amplifiers. The good news: the rules are simple and they don't change between a 500W single-amp install and a 5,000W competition system.
Gauge by current, not by amp size
Wire gauge is a function of current and run length. Use a power-wire chart, or follow the rule above. Aluminium-core (CCA) wire is rated lower than OFC at the same gauge — assume CCA needs to be one size larger.
Wire a Car Amplifier From Scratch
Run fused power from the battery, find a clean chassis ground, trigger remote-on from the head unit, and route signal cleanly away from power.
- 01Pick wire gauge from current draw
Total fuse rating ÷ 12V × 1.25 safety margin = required ampacity. A 100A fuse needs ~4 AWG OFC. Round up, never down.
- 02Fuse the power lead within 18 inches of the battery
ANL or MIDI fuse holder, sized to the wire's safe ampacity — not the amp's draw. This protects the wire, not the amp.
- 03Run the power lead through a grommet
Never share holes with brake lines or fuel lines. Use a rubber grommet at every metal pass-through to prevent chafing.
- 04Ground to bare chassis within 18 inches of the amp
Sand to bare metal, use a star washer, and keep the ground wire the same gauge as the power wire.
- 05Trigger remote-on from a switched 12V source
The blue/white wire on most head units, or an accessory-position fuse tap if you don't have a head unit remote output.
- 06Route RCAs opposite-side from power
Power down one side of the car, signal down the other. Crossing them at 90° is fine; running them parallel induces noise.