G'day
This forum is a great source of infomation.

What is the best way to run 4GA cable from the battery to the boot? Depending on the earth/grounding i might also run a negative from boot to battery to get a clean earth. So if there is room next to the positive i'll run a second cable.

Thanks

LN

hey

if your car is a AUTO then put it thoght the cluch cable hole in the firewall,if not then take the drivers side wheel off and remove the plastic s**t and there 's a hole in there that will come out near the kick panel ,you will be only able to fit one run of 4G thought the firewall as the hole is to small
for your earth find a part of the car chassie sand ther paint back so you can see metal and ground the cable there with a ring terminal or a big bolt or screw

cheers jarrod

Beautiful, thx.

LN

Problem i think...

I will have a 4GA cable running to boot with a 4GA cable running to the car ground near boot. But on my Negative terminal on my battery i only have a 8GA by the looks of it. Should that be upgraded? Else i can see it being a problem...maybe.

LN

if you got spare cable upgrade it, otherwise don't bother unless you're noticing a problem (noise).

one question, how much stuff are you running? as 4GA seems very very large for a "normal" install. I mean i run a 300WRMS sub PLUS i also run a set of Boston rally splits off an 8GA power and i am pretty sure that for a system like pyroay's then u would need 4GA otherwise for a normal setup, 8GA will be fine

I have a 2 channel amp that is rated at 50A current and I am going to be adding a 4 channel amp that is rated at 60Amp. 8GA cable is 50A rated and 4GA is rated at 120A. Sure the values are aimed at amps running at 100% volume (before cliping). but it'll be nice if i know that cable won't hold the power back. Or heating up losing power to amps.

Thou i will insert an amp meter and see what i am pullling, if i am below 50% power i won't bother.

LN

My general rule is for 5m cable runs (i.e. front of car to the boot)
- 8gauge for 1 amp
- 4gauge for 2 amp's
- 2gauge for 3 amp's
- 0gauge for 4 amp's or more...

Of course if you are running a boot mounted battery with short cable runs it is not necessary to run these cable sizes.

The longer the cable run and smaller the cable the more voltage drop you have accross it. The lower the voltage the more current that is drawn and that in turn leads to more voltage drop.

ANSWER
Specifically in response to your question, you should run 4 gauge. It is not much more expensive and is worth the little extra.

If your earth from the battery is lookinf a little tired then upgrade it too. 4gauge will be fine, because it is a short cable run...

Don't run the earth back to the battery run it to somewhere in the boot. Make sure you sand back the surface and expose the bare metal.