Do I really need 4 gauge wire to power a 400 watt amp?

ledvedder
10+ year member

Member
158
3
NJ
Going from a lot of suggestions, I ordered a 4 gauge wiring kit to wire my amp. Man, that wire is thick! I couldn't find a spot in the firewall to run it from the battery to the amp. Couldn't I use 8 gauge to make it a bit easier to run?

 

voltagexdt
10+ year member

Member
u can run 8 ga yes.

but heres what i tell my customers..

try to **** a milkshake through a coffee straw..

now try to **** it through a garden hose..

if you can get the 4 ga to work, when you decide to upgrade, your ready..

 

mat3833
10+ year member

CarAudio.com Elite
1,889
372
florida
run the 4 ga, technicly good 12 ga wire is rated between 35 and 50 amps constant current AC voltage(typicly ~40 amps is average). but bigger is almost always better. just go the 4ga run once and you will be set for ~130 amps constant(that works out to 1690W @ 13V) i went the "smaller wire first" route when i wired my first car. i ran 8ga and then 2 months later when i wanted to upgrade my sub amp and add a 4 channel amp for my comps i had to rip out the 8 ga and run some real wire. i wish i had just done it right the first time.

Matt

 

quackhead
10+ year member

HUH?
Going from a lot of suggestions, I ordered a 4 gauge wiring kit to wire my amp. Man, that wire is thick! I couldn't find a spot in the firewall to run it from the battery to the amp. Couldn't I use 8 gauge to make it a bit easier to run?
this is why they make drill bits and rubber wire grommets....run the big wire.

 

cdc351jeferson
10+ year member

CarAudio.com Elite
1,679
1
austin tx
run the 4 ga, technicly good 12 ga wire is rated between 35 and 50 amps constant current AC voltage(typicly ~40 amps is average). but bigger is almost always better. just go the 4ga run once and you will be set for ~130 amps constant(that works out to 1690W @ 13V) i went the "smaller wire first" route when i wired my first car. i ran 8ga and then 2 months later when i wanted to upgrade my sub amp and add a 4 channel amp for my comps i had to rip out the 8 ga and run some real wire. i wish i had just done it right the first time.
Matt
Errrrrrrrrrrr wrong 12g is good for 20 amps 8 for 50 don't tell him this or you'll have his burned down car on you

 

mat3833
10+ year member

CarAudio.com Elite
1,889
372
florida
Errrrrrrrrrrr wrong 12g is good for 20 amps 8 for 50 don't tell him this or you'll have his burned down car on you
American Wire Gauge table and AWG Electrical Current Load Limits with skin depth frequencies and wire strength -_- actually you are wrong. the ONLY reason his car could burn down is if he was pulling more current than its rated for. and most wire is rated for AC current, not DC. and since AC current runs a bit hotter and causes more wear and tear(generalized term) a 20amp AC wire can safely flow ~30% more DC current. and i told him to just run the 4ga, so its not on me.

but since im not spechial, you can win this race bro. im not an olympian.

Matt

 

sjv13
10+ year member

StayStrange
Thanks guys! I guess I'm gonna just try running the 4 gauge.
Yeah, this is really the way do it. You will probably upgrade and/or get another amp at some point, and you will already have half the job done. That's exactly what happened for me. Was really happy I only had to do it once. Just put a nice grommet in the firewall and you'll be all set.

 

cdc351jeferson
10+ year member

CarAudio.com Elite
1,679
1
austin tx
American Wire Gauge table and AWG Electrical Current Load Limits with skin depth frequencies and wire strength -_- actually you are wrong. the ONLY reason his car could burn down is if he was pulling more current than its rated for. and most wire is rated for AC current, not DC. and since AC current runs a bit hotter and causes more wear and tear(generalized term) a 20amp AC wire can safely flow ~30% more DC current. and i told him to just run the 4ga, so its not on me.
but since im not spechial, you can win this race bro. im not an olympian.

Matt
Well you run 50 amps on a 12g tell me how it works for you

 

mat3833
10+ year member

CarAudio.com Elite
1,889
372
florida
if i had 12 ga that can take it, i would. the only thing that uses 12 ga that i own(asside from speaker wire for my tower speakers) is my poor mans lathe in my garage. the motor is powered by 6 volts@40 amps under high load. granted the length of wire is only about a foot. but i have yet to have a problem even after working with steel rods on the lathe. everything else electrical that i own runs the biggest wire it can fit. hell even my subs run 10ga or higher, and they only have 35W each right now.

Matt

 

dragon.breath
10+ year member

Senior VIP Member
1,210
447
Al
Bigger wire than necessary will not hurt anything except your wallet. You will be fine.

I probably would have started a new thread instead reopening one from 14 years ago.
 
Activity
No one is currently typing a reply...

Similar threads

Thanks a lot. iPhone charging. Wow. No cigarette lighters now.
35
5K
If you have that much then yeah go for it. It's incredibly nice to just have the option. I remember the first time driving after I put it on...
16
3K
Error was fixed by soldering their connector on mine, mine wasn't color coded (e.g. red - switching power, yellow - constant power etc.) It was...
6
1K

About this thread

ledvedder

10+ year member
Member
Thread starter
ledvedder
Joined
Location
NJ
Start date
Participants
Who Replied
Replies
12
Views
15,817
Last reply date
Last reply from
dragon.breath
IMG_0381.png

DEW123

    Mar 3, 2024
  • 0
  • 0
1709406705908.png

Doxquzme

    Mar 2, 2024
  • 0
  • 0

Latest topics

Top