something i have just always wondered about car audio. wire size limiter?

[eb2phkingood 10+ year member]

before i ever owned an amplifier i ran 12 gauge wires to all my speakers, but the wire coming out of the back of my kenwood hu was probably 18-22 gauge or somewhere in there. so what was the point of the 12 gauge wire if the 18-22 coming out of the hu is limiting the current anyways?

second, right now i have my hu ground in the same location of my amps. to do this i ran a 12ga wire back to the ground location. once again, whats the point of 12ga when my ground coming out of my hu is probably a 22ga wire??

please enlighten me and thx in advance!

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[Bfat567 10+ year member]

Your wire is only as strong as its weakest point so i dont think there is a point.

 

[Vossy 10+ year member]

for how much the power the HU has, stock wires work

 

[bubbagumper6 5,000+ posts]

for how much the power the HU has, stock wires work

That's debatable...stock wires are meant to handle the power of a stock headunit...some headunits are powerful enough to need larger wires. If you actually read your manual most of them tell you to run dedicated power and ground wires and NOT to just tap into the stock wiring.

 

[Vossy 10+ year member]

That's debatable...stock wires are meant to handle the power of a stock headunit...some headunits are powerful enough to need larger wires. If you actually read your manual most of them tell you to run dedicated power and ground wires and NOT to just tap into the stock wiring.

they also recommend 4 gauge for 40 amps.

 

[bubbagumper6 5,000+ posts]

they also recommend 4 gauge for 40 amps.

So?

 

[VWBobby 10+ year member]

Also, the longer the wire run, the heavier the gauge needs to be. For runs over 10-15 feet, I would always use 12-16 gauge speaker wire. For runs over 20-30 feet, it would be best to drop down to 12-gauge.

The average headunit only puts out about 22-watts RMS per channel, if that, not really much need to go above 16-gauge speaker wire, same for power and ground.

 

[helotaxi 5,000+ posts]

That 22W is also at around 10% distortion and heavily clipped. Most struggle to do 15w cleanly.