Stereo & Electronics - What size power wire?

Hello All-

Didn't find anything too helpful. I'm about to start my stereo install and want to make sure I do the wiring right.

I only have 2 amps:

1) 2x150w RMS going to the front components (2x300max)
2) 2x100w RMS going to my DVC sub (400 w max)

I anticipate running the rear seat speakers off the headunit just for midbass fill. I MAY power them down the road with an amp, but not anytime soon.

What size power cable should I run? Should I run a common ground as well, or ground the amps individually in the rear? Thanks for your help :chug:

8 guage should be fine but i would use 4 guage because you never know when you want to up grade or add stuff etc.

4 gauge definitely, I ran 500watts off of 8 ga. once and it was hurting me.

Go 4 ga. You'll have room to grow in the future.

4 gauge for sure, room for growth...also use seperate grounds both 4 guage as well.

Thanks for your help, fellas.


What would you consider the limit for 4 gauge power in our car? It seems like you'd need a ton a power to require 0 gauge

Thanks for your help, fellas.


What would you consider the limit for 4 gauge power in our car? It seems like you'd need a ton a power to require 0 gauge

I ran 1/0 in my last system. Was running a 250w RMS amp off of it though.

Limit for 4 AWG really depends on the length. The shorter the length, the more it can handle. The chart is pretty helpful when it comes to determining when you should move to a bigger size.

http://img242.imageshack.us/img242/6880/wirecharttr5.jpg (http://www.imageshack.us)

I ran 4Ga off battery to inline fuse, then back to rear of car, into a fused distribution block, then 8Ga power wire to each amp.

Used 8Ga for Ground on each amp.

Just make sure you run the power wires for the amps up one side of the car, and the signal RCA Cables from HU to amps up the other side of the car, so you do not impart any 'noise' into your signal cables from power wires.

-Jay-

what kind of amps are you using?

Ive got a few "50" watt amps that are 1/4 ohm stable :devil:

what kind of amps are you using?

Ive got a few "50" watt amps that are 1/4 ohm stable :devil:

What the original poster should be looking at is the total possible current draw of his system measured in amps. Total up the numbers on the fuses on all the amplifiers (ex. amp1 is 20A, amp 2 is 40A = 60A total) to figure out your total possible current draw. Then use the chart Element posted. That will tell you how long of a run of cable you can do before you see .5v of voltage drop at the amplifiers. Also, as 2MuchRiceMakesMeSick pointed out, sometimes certain "50 watt" amplifiers can draw 100A such as Orion HCCA or some US amps "cheater" amplifiers.

Thanks for your help, fellas.

What would you consider the limit for 4 gauge power in our car? It seems like you'd need a ton a power to require 0 gauge

I am running about 1000 watts RMS in my car, and I am using a 150A fuse at the battery. I use 1/0 gauge all the way to the back where it is split into 4 two foot pieces of 8 gauge, each to an amplifier. I usually see less than a .2v difference between the voltage at the battery and the voltage at the distrbution block.

Thanks to all who have replied-


So what I'm taking away from this is that I should try to not have more than 0.5V drop going back to my system? I will look into the amps of the system and use that great spreadsheet.

Follow on question- is there a similar chart for speaker wire? I'm looking to purchase a spool of wire for this install, but I want to make sure I get the right size (16, 14, 12, etc). Thanks again, you guys have been very helpful!

Just say to hell with it and do 0ga front to rear. It opens up possibilities such as adding more amps or you could relocate your battery to the rear without re-doing the wiring. Either way, voltage loss will be minimal. I don't even mess with anything smaller anymore. It's not that expensive either. Just do it once and your set.

If you care about looks, then it's bitch'n in that regard as well.

Thanks to all who have replied-


So what I'm taking away from this is that I should try to not have more than 0.5V drop going back to my system? I will look into the amps of the system and use that great spreadsheet.

Follow on question- is there a similar chart for speaker wire? I'm looking to purchase a spool of wire for this install, but I want to make sure I get the right size (16, 14, 12, etc). Thanks again, you guys have been very helpful!

Your amps will be able to put out more power with more voltage. You ideally want 14vdc into your amps. If you had a 1vdc drop because of using 8 gauge, your amps would see 13vdc instead of the 14vdc at the battery. Then you would not be seeing the full potential of your system.
There is not a similar chart for speaker wire because there is not as much current draw through the speaker outputs from the amp. Just use 16ga for all your mids/highs, and 14 or 12ga for your subs if you are running lots of power to them. Just don't use tiny wire for long runs (ex. 18-20ga runs from the amps in the back to speakers in the front.)

A 1 volt drop can be huge to the amp. Possibly reducing power by 30% or more. There's a lot of factors, but generally the less resistance the less voltage drop and more power to the speakers.

I used 4 ga and I'm powering 2 JL 250/1's and a 300/4.