Wiring Question

[Mikes91]

As you know, I'm working on adding a distribution box with independent fuses for the aftermarket accessories on my truck. I've already run some wire from gauges, and intend to run other wire soon.

I don't like the thought of individual wires running free along/under my truck, so intend to put the wires into split flex tubing to protect them.

Was wondering if it is standard practice to run the positive wires and ground wires through the same piece of flex tubing. I ask this with the thought that several years of rubbing might cause the insulation on the wires to wear through leading to a short circuit.

Am I overly concerned about this? Perhaps in practice the wires won't rub through, particularly since they're surrounded by flex tubing (after all, the factory wiring isn't shorted after 15+ years of use). Since the circuits will be fused a short shouldn't be too big a deal... Just want to know what is accepted practice so I can do the job right.


Thank you,
Mike

 

[jlayne]

most cars and trucks with a 12v system don't have ground wires that run all the way back to the source... all you need to do it make a short wire to the nearest metal object and it will them be grounded... the chassis/body is the ground

i run all of my wiring through the plastic sleeves... but not the neg.. i ground those to something metal near by

 

[Mikes91]

most cars and trucks with a 12v system don't have ground wires that run all the way back to the source... all you need to do it make a short wire to the nearest metal object and it will them be grounded... the chassis/body is the ground

i run all of my wiring through the plastic sleeves... but not the neg.. i ground those to something metal near by

There's a handy bolt under the dash I could use for that purpose. Already used by 2 other old aftermarket add-ons.

I like your idea better than running pos and neg wires long distances... more robust.

How are fuse connections typically made? I like the idea of running positive connections to a common box under the hood. I assume one side of the fuse is connected to the positive wire to my accessory, the other of the fuse is connected to the positive voltage source? Been studying too late tonight, my mind is on the fritz and I may be entirely off the mark here.

Thank you,

Mike

 

[wwwabbit]

I can't see any problem with the wires being together... I mean how many miles of wire is loomed together in the truck from the factory? It's always looked good when I have taken apart old wireing harnes's.

As for fuses, fuse right away after the battery! Don't wait (I speak from experance on this one) Since I just about burnt down my Mazda that I had, I fuse everything, and make sure the fuse is the right value for the wire, eg. putting a 30 amp fuse on a 22gauge wire is not going to help. My self, I have a larger then I need 0 gauge wire from the battery to my fuse block, fused at the battery with 60 amp fuse. From the fuse block I split off to my relays for lights, radios(CB and HAM), stereo, etc. I find I have clean power to everything, and everything has protection. If your wireing is good, you should not need any extra fusing at the device, as it should blow the fuse that is powering it from your fuse block should something in the device fail. That means though, that you can't "double up" on stuff (eg. run a set of high powered lights and a small gauge light) off one fuse because if the small gauge light shorts out, it would not be able to draw enough current to blow the fuse.

As for the grounds... I don't trust the rusty old grounds that are on any vehical... Clean your grounds, cab to frame, cab to motor, motor to batteries, batteries to frame, etc. Check and clean them all. For anything that is extra sensive to that sort of thing, I normaly run a ground right back to the battery. For gauge lights and little things like that, your dash/cab/frame grounds are going to be good enough.

 

[flatlander]

Definitely ground everything in the shortest distance possible. DC power is notorious for voltage drop (resistance in the wiring "eats" available voltage resulting in lower voltage to the electrical component). If your voltage is lower, then your current is higher. Plus electric motors work harder, live shorter, etc. . .

So, fuse everything on the positive side. Run a little bigger wire than necessary. Ground quickly and securely.

 

[jlayne]

flatlander has the ticket, a frame/body has much more metal to carry electicity that any wire... so it will have much less voltage drop

if you wanted to make a power distribution box i would use a large wire such as those used for audio amps with a large inline fuse near the battery (both available at walmart, radioshack, or audio installer as a kit).. then connect that to the distibution block with smaller fuses the correct size for each wire/gizmo

i have even seen the old style ford starter solenoids used on the main wire before the distribution box with a toggle switch to create a super heavy duty relay for a auxillary power on/off.. you might do some research on this to get the correct part numbers

just some thoughts