Car Audio
Car Audio Wiring Gauge Guide | Power, Speaker & RCA Cables
Blackout Team· Window Tinting Experts
·6 min read
Complete guide to car audio wiring. Learn the right wire gauges for power, ground, speaker, and RCA cables for your system.
Car Audio Wiring Guide
Wrong wire = problems. Undersized power wire causes amp shutdowns. Thin speaker wire loses power. Bad grounds create noise.
This guide covers every wire in your system.
Power Wire (Battery to Amplifier)
Why It Matters Most
Power wire carries ALL the current your amp needs. Too thin = voltage drop = amp shuts down or clips.
Power Wire Gauge Chart
| Amp Power (Total RMS) | Wire Length 0-4ft | 4-7ft | 7-10ft | 10-13ft | 13-16ft |
|---|---|---|---|---|---|
| 0-200W | 10 AWG | 10 AWG | 8 AWG | 8 AWG | 4 AWG |
| 200-400W | 8 AWG | 8 AWG | 4 AWG | 4 AWG | 4 AWG |
| 400-800W | 4 AWG | 4 AWG | 4 AWG | 2 AWG | 2 AWG |
| 800-1500W | 4 AWG | 2 AWG | 2 AWG | 1/0 AWG | 1/0 AWG |
| 1500W+ | 2 AWG | 1/0 AWG | 1/0 AWG | 1/0 AWG | 1/0 AWG |
Key Points
- Measure actual run — Door sills, under carpet, through firewall
- Round up if between — 4 AWG borderline? Use 4 AWG or 2 AWG
- OFC vs CCA — Oxygen-free copper (OFC) is better; CCA needs one size thicker
Ground Wire
The Rule
Ground wire = same gauge as power wire
Your ground completes the circuit. Weak ground = noise, amp problems, poor performance.
Grounding Requirements
- Clean bare metal — Sand paint off, use star washer
- Short as possible — Under 18" ideal
- Solid connection — No rust, no paint, tight bolt
- Multiple grounds — Large systems benefit from dual grounds
Fusing
Main Power Fuse
Required within 18" of battery. Protects your car if wire shorts.
| Power Wire | Fuse Size |
|---|---|
| 8 AWG | 60A |
| 4 AWG | 100A |
| 2 AWG | 150A |
| 1/0 AWG | 200-250A |
Amp Fuses
Most amps have internal fuses. External fuse protects wire, not amp.
Speaker Wire
Speaker Wire Gauge Chart
| Run Length | Standard Power | High Power (100W+) |
|---|---|---|
| 0-10ft | 16 AWG | 14 AWG |
| 10-20ft | 14 AWG | 12 AWG |
| 20-30ft | 12 AWG | 12 AWG |
| 30ft+ | 12 AWG | 10 AWG |
Speaker Wire Notes
- Most installations: 16 AWG or 14 AWG works fine
- High power: 14 AWG or 12 AWG for runs over 15ft
- Subwoofers: 12 AWG recommended (high current)
RCA (Signal) Cables
Quality Matters More Than Gauge
RCA cables carry voltage, not current. Quality over size.
What to look for:
- Shielding — Prevents noise pickup
- Good connectors — Tight fit, quality metals
- Twisted pairs — Rejects interference
- Reasonable price — $20-50 is fine, $10 cables work too
RCA Cable Lengths
| Amp Location | Cable Length |
|---|---|
| Under seat | 6-9 ft |
| Rear seat | 12-15 ft |
| Trunk | 15-20 ft |
Remote Turn-On Wire
The Basics
Small wire (18 AWG is fine) that tells amp to turn on when head unit powers up.
Sources:
- Blue/white wire from aftermarket head unit
- Switched 12V source (ignition)
- Add-a-fuse with ignition-switched fuse
Wire Routing Best Practices
Power Wire
- Run on OPPOSITE side from RCA cables
- Through firewall grommet (don't drill bare metal)
- Away from factory wiring when possible
- Under carpet, along door sills
RCA Cables
- Run on OPPOSITE side from power wire
- Avoid crossing power wire (if must cross, 90° angle)
- Bundle with speaker wire if helpful
Speaker Wire
- Factory wiring paths work well
- Use split loom for protection
- Don't pinch in door jambs
Complete Wiring Kit Guide
What's in a Kit
- Power wire (main run)
- Ground wire (short piece)
- Fuse holder + fuse
- RCA cables
- Remote wire
- Ring terminals, connectors
Kit Recommendations by System
| System | Kit Size |
|---|---|
| Small amp (under 500W) | 8 AWG kit |
| Medium amp (500-1000W) | 4 AWG kit |
| Large system (1000W+) | 1/0 AWG kit |
Quality Matters
Avoid: Super-cheap Amazon kits with CCA wire Better: Brand kits (Kicker, Rockford) or bulk OFC wire
Common Wiring Mistakes
Mistake 1: Power Wire Too Small
Amp works at low volume, cuts out at high volume. Upgrade wire.
Mistake 2: Bad Ground
Causes: noise, amp shutdown, no power. Check and redo.
Mistake 3: No Main Fuse
Fire hazard. Always fuse within 18" of battery.
Mistake 4: Power and RCA Running Together
Causes: alternator whine, engine noise. Separate them.
Mistake 5: Pinched Wire
Exposed copper = short = fire or damage. Use grommets.
Ready for Professional Wiring?
Proper wiring is invisible but critical:
📞 Call 408-848-8468 — discuss your setup
📍 Visit our Gilroy shop — see our work
📝 Get a free quote — we wire it right
Related Content
- Amp Power: Do I Need an Amplifier?
- Amp Tuning: How to Set Gain Correctly
- Full Service: Car Audio Services
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