Recommendations for type of wire

[jamespwsullivan]

I have a 1987 MJ that is in many ways in very good condition, but it has sat for quite a while so I am starting to redo some (probably all) connections in the fuse box and I suspect that the PO has made some “changes” to some of the wiring as well.  I’ve been looking at wire that is appropriate for in-cab / under dash, engine bay and under the bed applications and I’m confused with the choices.

 

It seems that I should use something that will withstand higher temperatures in the engine bay and maybe even in the cab.  Automotive GPT is rated for 185 deg F and Cross-Link is rated for -40 to 257 deg F.

https://info.waytekwire.com/blog/automotive-cross-link-vs.-pvc-wire-what-are-the-differences

 

I’m looking for some recommendations for which type should be used and where?  One type for every thing?  I don’t plan to remake the entire wiring harness but some new runs will have to be made in the dash and in the engine bay for sure. 

 

Also, is most of the wire in the dash 16 gauge or 14 gauge?

 

Thanks

[AZJeff]

Most of the wires are 16-18 guage in typical auto applications such as ignition, gauges, instrument panel stuff, and the like.  Of course, charging/starting circuits will be larger, as will be some of the lighting.   All of it, of course, is dependent on how long the wire run is, becuase the longer the run, the more voltage drop there will be.

 

Your best bet is to look at what size the fuses are for each given circuit.  You want your wires to be able to carry MORE current than the fuse will allow.  The last thing you want to have happen is for the wire to overheat/melt before the fuse blows (unless you are trying to duplicate wiring from a typical Britsh automobile from the 1960's)

 

The attached chart should give you some good recommendations as to what wire guage you need for a given current draw.

 

Using the above chart, and picking a hypothetical example:  

-- Let's say a given circuit is fused for 10amps, and lets say the the wires run from the headlamp switch to the tail-lights, which is a run of about 15 feet.  

-- The chart says the MINIMUM wire size to use would be 16 guage wire.  

-- To be safe, I would use NO SMALLER than 16, and maybe even 14 guage to be safe.

 

By the way, if you want REALLY good connections, any time you splice wires together, rather than using regular butt splices, try to solder your connections and use heat-shrink tubing to seal and insulate them.  Those connections will be as good or better than OEM.

[Big Dan]

I may be in the minority, but, I will disagree with soldering on vibration heavy applications. A solid crimp, and heat shrink, is a more stout connection.
There are applications for soldering. But, I find myself using it less and less.

Sent from my Pixel 4 XL using Tapatalk

[AZJeff]

10 minutes ago, Big Dan said:

I may be in the minority, but, I will disagree with soldering on vibration heavy applications. A solid crimp, and heat shrink, is a more stout connection.
There are applications for soldering. But, I find myself using it less and less.

Sent from my Pixel 4 XL using Tapatalk
 

I guess the secret to my suggesting solder is that I am a BIG fan of wiring looming (the corrugated type stuff) and Tie-Wraps (nylon wire ties).   My wiring tends to be pretty secure, and because of that, I have never had a solder joing crack due to vibration.

[Minuit]

There is a time for solder and a time for crimping.

 

If you solder a connection and that connection is going to move whatsoever, it must have adequate strain relief. In other words, the soldered area must be supported by something.

 

I am not a fan of the red/blue/yellow crimp butt splices, and I especially hate the ones with hard insulation. They're too bulky. A properly soldered inline splice should be approximately the size of the un-stripped wire and will be strong, as long as you've soldered it properly and didn't use crap solder.

 

Most crimp terminals (other than the non-insulated ones that are designed to be used with heat shrink tubing) contain some measure of a strain relief section which is crimped around the wire's insulation. A proper crimper will crimp the main wire section and the strain relief section simultaneously. Just like on a soldered connection, you don't want any bending to happen right where the copper is crimped.

 

Proper crimp tooling creates a compression weld between the terminal and wire - that means if you were to cut the crimp, you would see one mass of copper with no air gaps whatsoever. If you don't have proper crimp tooling, don't bother. A pair of pliers is never the right answer. A ratchet crimper with interchangeable dies is the bare minimum I would consider acceptable. Those will get you to about 12 AWG. Any bigger than that and it's time for a hydraulic crimper, which are awesome by the way.

 

Finally, if you're going to use crimp terminals, USE GOOD ONES. The crap you find at the auto parts store isn't good enough. I order mine through the electronics distributors Digikey or Mouser, whichever I happen to have a cart going with at the time. Molex and AMP both have quality products.

 

I'll never advocate soldering a terminal that has already been crimped.

 

Here is one of my favorite places to get wire, especially as someone who often needs to build harnesses with small runs of specific color/stripe wire. The site is antiquated, but the product is quality. https://4rcustomswire.com/ All of their wire is cross-linked. I wouldn't personally want to use PVC insulated wire on a Jeep, especially considering how often our trucks tend to let the outside stuff in, but I do tend towards the "build it for a nuclear apocalypse" school of wire harness design.

 

Maybe that

[jamespwsullivan]

Thanks everyone!  I really appreciate all of the replies.  Maybe I should have looked harder for a “Basic Wiring Tips” topic?  Maybe a sticky?  There’s a lot of information here and all of it either something I knew already (but might have forgotten) or something I need to know moving forward.

 

For the record, I will solder where appropriate and I certainly agree with the idea of keeping soldered connections supported and weatherproofed.  I tend to stay away from butt connectors although I have used a few of the low-temperature solder type recently when I had a heat source but no soldering iron.  Maybe good for emergencies?

 

I’m also familiar with the ratcheting crimping tools.  Using them isn’t part of my backcourt but I have used a buddy’s and it did a great job.  One thing mentioned by @Minuit that I had not paid attention to is when the crimping tool manages both the electrical connection and the strain relief.

 

Regarding the fuse block and the connectors from Del City. https://www.delcity.net/store/4!way-Fuse-Block-Terminal-Strip/p_11129.h_26968

I’ve read that some have soldering wires to them, some have used the solder pellets instead of solder from a spool, and some have crimped.  Does anyone have any further input on what works best for the fuse block?