Where will this panel be mounted?
Battery is by nature the "best" but it's often the least convenient too.
As long as your main grounding scheme is sound, you can ground the new panel just about anywhere because your whole rig will be well grounded.
But in lieu of perfection (hey, it's a Bronco, right?%)) find the next best things to the battery. That's usually near the main body and engine grounds if feasible.
The alternator is not a bad place, but maybe if you're that close, grounding to the main engine ground cable point is even better.
Just remember that the power feed
AND the ground need to have the same capacity.
Personally, even though I like 8g wire, I think it's a bit overkill unless you're going to keep the fuse panel far away from the battery and power heavier than normal loads through it. Especially over short distances, a 10g wire would be easier to run and have plenty of capacity.
The length and maximum load indicates what gauge wire is needed.
Even a 10g wire can handle 120amps over a short distance for awhile. The factory setup was 15 to 20 feet or so of measly little 10g wire. Nothing exotic and it could handle the stock optional 60, and upgraded 70 amps for reasonable periods with zero issue. Did it on mine with dual batteries running refrigerators, lights and all sorts of fun stuff like that for years.
Six inches of 8g could probably handle 250 amps. Can your fuse panel? Would it even need to?
Is the relay you'll be using capable of more? Most standard relays are either 30a or 40a rated. For this panel you'd want a heavier one for the main circuit. For example a 70a rated relay. If so, 10ga is likely more than enough still.
So using Charlie's 50a rated fuse scenario (down from 60a), you can easily protect a 10g wire with that. It's what some of the full harness manufacturers like Painless use in their systems as well. A single 10ga wire over several feet, feeding the entire 20+ fuse panel, protected by a single 60a Maxi-Fuse.
Painless has upgraded their main fuse for their 10g charge line from the old 60a version to a 70a version if I'm not mistaken.
I'd be interested to hear more of what Charlie's research has told him about the 50a fuse need. This is important stuff, so any new information is good.
Even though I'm big on overkilling battery and starter cables, I agree using closer to your need for other stuff, rather than just over-killing unnecessarily is a good thing. That includes the wire gauge as well as the fuse rating.
And that 50a is all the more reason that you don't need 8g wire.
Did you decide this is going to be your main panel, or a sub-panel? Is it going to be handling all duties, or just some?
Are you going with the single-stage, or dual-stage (keyed
AND constant) versions?
What is it's maximum rated current capability?
Maybe that's more info than we really need for this relatively simple-in-concept production. But Enquiring minds need to know...
%)
Thanks
Paul
