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New_Toyz 04-18-2002 04:40 PM

Whats a good donor fuse block for my 3a
Some of you pic-n-pull experts can help me out here. I'm looking for a good modern fuse block to put in my 3a. Something that is plentiful and easy to remove since the pickings will be slim.

Jim_Lou 04-18-2002 05:23 PM

Re: Whats a good donor fuse block for my 3a
Before you get a junkyard box, check Painless Wiring at They have fuse blocks that have screw terminals, which will be a lot easier to deal with than the weird connectors on OEM fuse blocks.

**DONOTDELETE** 04-18-2002 05:24 PM

Re: Whats a good donor fuse block for my 3a
I have a 70' CJ5. I re-wired mine with aftermarket fuse blocks from a speed-shop. They are very simple and easy to install and after 5 years I have had no problems. They are also a lot cheaper than going with a painless wiring kit.

bluseman2a 04-18-2002 09:40 PM

Re: Whats a good donor fuse block for my 3a
How about a 10 gang power and ground distribution block that uses standard ATO fuses and spade connectors? How about if 10 isn't enough you hook another onto it for 14 or 20 gang? How about 150 amp rated? How about $20 for it?

Oh, you wanted surface mount?
<a target="_blank" href=></a>

For those prices I find it real hard to crawl around junkyards when I can have something new that I know will work at a fraction of what Painless and the likes charge...

Caver Dave 04-18-2002 10:12 PM

Re: Whats a good donor fuse block for my 3a
Dang Herb. I've been waiting for you to post your sources of all those slick wiring parts you've got since Dec!
My question is: does anyone have a list of the recommended fuses for all the individual circuits and the "feeder" for the fuse block? The 'mando is in dire need of some wiring upgrades. The original wires are mega brittle and the thermal circuit breaker (1-30A has everything but the headlights [img]images/icons/shocked.gif[/img]) is beginning to trip when it's raining or humid.

bluseman2a 04-19-2002 07:12 AM

Re: Whats a good donor fuse block for my 3a
Hey Dave, I wasn't keeping it a secret, I PROMISE. I think I've posted that a couple of times between here, JU and POR. Heck I figured people would be getting sick of it by now.

Figuring the load is pretty easy. Start with P=IE.
Where P= Power (in watts)
Where I= Current (in amps)
Where E= Electromitive force (in Volts)

Figure that your "average" running voltage is 12-14 volts, then use 12 for safety's sake. Most of the stuff you'll probably be using is light-related, so just add the wattages for all the bulbs on a run together and solve for I.

Example: headlights at 100W each: 200W=I*12. Switch it around and you have I=200/12 which is 17amps. I generally add a safety margin of 10-20% and you come up with about a 20-25 amp fuse. The more delicate the electronics you are running, the less you want that safety margin to be.

If that doesn't work, you can V=IR
Volts=Current (in amps)*Resistance(in ohms)

Again, we know voltage to be 12-14
Hook a multimeter to the power lead for the run and measure resistance to a GOOD ground (note if you are hooking things in PARALLEL, this will make the resistance go DOWN, so measure it the way you are going to run it).

Example: Tail lights, the circuit has a total resistance of 10 ohms. Plug that in and we have 12=I*10. Solve for "I" and you get I=12/10 or 1.2 Amps.

Factory supplies for the fuse panel are 8-10 ga. wire, but I'm a belt and suspenders man, so I say use 4 Ga welding cable for power and ground supplies.

For the "total" for the box, figure your entire load, add some extra overhead for future expansion, then buy the closest master switch listed above.

Dave, if you need anything else, lemme know, either AIM me or email.

New_Toyz 04-19-2002 10:30 AM

Re: Whats a good donor fuse block for my 3a
Thanks for those links. Looks a lot better than what I was thinking.


bluseman2a 04-19-2002 10:38 AM

Re: Whats a good donor fuse block for my 3a
NP, I'm anal about clean, simple, functional, affordable electrical, glad I could help.

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