Best wire for under a vehicle?

[rodm1]

I have a few wiring projects (gate lock, bed lights, power) for my truck and am looking for the very best wire for this project. Looking for something with an outer jacket like extension cord but that can stand up to years of salt and wet conditions. Any ideas where I can find this?

 

[mike93lx]

I have a few wiring projects (gate lock, bed lights, power) for my truck and am looking for the very best wire for this project. Looking for something with an outer jacket like extension cord but that can stand up to years of salt and wet conditions. Any ideas where I can find this?

For heavy gauge, welding wire is about the best. Everything should be put in loom and mounted in a way that protects it from damage.

Connection quality is way more important.

 

[joe_padavano]

I think you're way overthinking this. Millions of vehicles on the road work just fine with regular automotive wire running along the frame. Salt and water isn't going to affect plastic insulation. The problem is the connectors. Use properly crimped Weatherpack connectors. DO NOT use the red/yellow/blue crimp connectors, and definitely do not use Scotchlock connectors.

 

[tarmy]

In certain situations I use boat wire from West Marine...it is tinned and is expensive...but for areas that get rubbed and wet I have found it good to use. Either way, as others mentioned, protected with wrap and good connectors are just as important...

 

[shaggyant]

I try to use XLPE insulated wire instead of the old school PVC wire. It’s better in high heat and chemicals.

https://www.waytekwire.com/products/1454/Automotive-Cross-Link-Wire/

 

[bwringer]

"Marine Cable" or "Brake Cable" comes with a jacket around two, three, or four wires.
https://www.waytekwire.com/products/1461/Marine-Wire-Cable/
https://www.waytekwire.com/products/1458/Brake-Cable/

For your application, that's what I'd use.

 

[matt_i]

Imo if you want to build vehicle-quality wiring you need weather-packed connectors. The GM-Delcotronics versions are out there. Everything should be gasketed OR heat-shrinked, but the heat-shrink tube MUST CONTAIN GLUE inside of it. It can't just be the black tube because that just leaks. Panduit makes some **** splices with a BSH- part number that aren't cheap but fit the bill.

I use THHN wire as its more expensive than any "automotive" PVC jacketed wiring. THHN is water, oil, and fuel resistant. Very tough jacket. I used this on my pickup truck's underbody trailer harness in 2004 and while I try to avoid all salt it has seen plenty of rain and I have not ever touched it since.

Last is to give the wire harness additional chafe resistance, I like the split black conduit, I typically buy the higher-temp version at McMaster Carr but there might be a better source.

Any ground wire I use a thru bolt, stainless steel star-washers and slather with Jet Lube SS-30 pure copper anti-seize. I think a good coating of pure silicone caulk or dielectric grease would also be good. That one is typically exposed and all of the others rely on it in a negative-chassis ground system.

I have also rewired my 3 tractors with same ideas, there are a few exposed ring terminals and I'm only 2 years into it but all is working much better than before.

 

[rodm1]

Thanks guy's that is what I'm looking for.

 

[theoldwizard1]

First, the wire itself. I highly recommend using "marine" grade wire. It is copper, but it is stranded pre-tinned (dipped in molten solder before the insulation is applied) so it has excellent corrosion resistant properties. (It also is easy to solder it that is your plan.) The multi-conductor versions are sheathed similar to NM-B.

Another source for marine wire http://www.genuinedealz.com/marine-wire.

I also recommend using convolute protective tubing. Finish the good quality PVC electrical tape (3M Scoth 88).

 

[sberry]

I do it a lot of ways. Use cord and use thwn too. My favorite is rolled poly pipe. You can puncture it with an awl and insert a wire, even small cord and it closes around it. Wire nuts dilled with silicone work in exposed conditions but I like running the pipe into boxes and thru common cable connectors which allows wire ri be pushed.
Over the years have come up with variations but usually put a box over the studs on the fixtures, which keeps grime off.
The trick to this is spray. I use wire nuts, after they are on stick the little straw from the spray can in and give them a shot, it capillaries in to the wire, I orient the nuts up, spray the inside of the box and threads on screws on connectors and covers. Then silicone any holes in top of boxes and bead on the cover 3 sides.
I have these decades old, next to **** with fancy splice **** and it outlasts them all. Took one apart was on for 25 years and wires like new, springs in wire nuts were good. These are on trucks and trailers in road salt, constant pressure washing, used on ruffuff brutal roads.

 

[sberry]

And,, no, the wire nuts do not fall off or come loose, quite the contrary.
There is one inside box after 25 years, even the screws came loose. Note how clean wires are.

 

[s14kev]

I try to use XLPE insulated wire instead of the old school PVC wire. It’s better in high heat and chemicals.

https://www.waytekwire.com/products/1454/Automotive-Cross-Link-Wire/

This is the correct answer. The primary wire sold at auto parts stores, lowes/HD etc is generally garbage PVC insulated. None of this will withstand long term abuse. Modern automotive harnesses designed to live in the harsh environment of engine bays all use cross link polyethylene insulated wire. GXL and TXL is now my go to for any automotive wire. I've pretty much stopped stocking cheap PVC wire in my home shop and only keep TXL/GXL of various gauges and colors.

 

[Bretny]

Step away from the wire nuts my friend. They have no business being any where on a vehicle. You need to seal the wireing.

Also dont use THHN its house wite for houses. Use marine or stranded primary wireing with heat sealable connectors.

I use to be a diesel mechanic that worked on state plow trucks. Anything not sealed wouldnt last more than two winters. If you cant do a good job of sealing it use dielectric grease. For instance starter terminals or battery lugs.

 

[fasteddie]

I ran a length of 1/2" blue PVC flex conduit from the engine bay back to the rear wheel area on my pickup. It's strapped to the outboard side of the frame rail. I originally installed it when I converted to an electric fuel pump located back near the tank but it came in handy for some other wiring I needed back there subsequently. Sure beats crawling under the truck to run wires and they are very well protected.

 

[ransil]

Gxl, txl or sxl auto wire should work.
Like others said proper termination is gonna provide longest life.

Sent from my SM-G920V using Tapatalk

 

[sberry]

I have had these in service for 30 years, 20 before you started in this business, hundreds of them. If one reads carefully they are deliverately installed, not flung on, not dry and hanging under the bumper. In this time I have seen dozens of connectors installed by every scheme imaginable and expense, nothing is as secure and reliable.
Have seen 100s of failed connections, shrinked, factory, butts, crimps, even those juice filled ones that are better but ehen they breach they trap water. Look at the condition of the wire in the pics, that particular one 30 years.
Have never used a scotch lock. Do have the big box with most they ever invent.

 

[sberry]

I am curious, how would the electric know if the wire was for a house?
As a matter of fact have seen orange extension cord outlast the truck its installed on if its hung up and doesnt get damaged. Even a simple **** splice will last a long time if its shot full of spray when its installed.

 

[American Locomotive]

Get proper marine or automotive wire. Tape the strands together every foot or so and encase it in that plastic wire loom sheathing. That's what most chassis wiring uses these days.

THHN house wire is coarsely stranded and does not deal well with heavy flexing and vibration. Additionally the PVC jacket THHN has will become extremely brittle at cold temperatures and be more prone to cracking.

Wirenuts do not belong on a car, especially underneath them. I've seen tons of hacked wire nutted connections fail on cars.

 

[sberry]

There is a difference with a hacked job, this is carefully installed and outlast every piece of equipment its installed on. Seen plenty of **** connections not with wire nuts. The only problem I have seen with the wire is exposed to sunlight, outdoors. Like any wire if you want it to last shirls, pipe it. There is lots of cracked factory and trailer wire.

 

[sberry]

I have been at this a while, hard to fathom 40 years now. I havnt seen tons but probably north of hundred pounds of it and probably see more than hobby types. I have a chance to see it on a lot of the same equipment long term.

 

[Git]

https://www.waytekwire.com/products/1453/Wire-Cable/

Go to Waytekwire - they are a large supply house that has catered to the automotive industry for years. They know what they are doing and you will find what you need

 

[gte718p]

Get proper marine or automotive wire. Tape the strands together every foot or so and encase it in that plastic wire loom sheathing. That's what most chassis wiring uses these days.

THHN house wire is coarsely stranded and does not deal well with heavy flexing and vibration. Additionally the PVC jacket THHN has will become extremely brittle at cold temperatures and be more prone to cracking.

Wirenuts do not belong on a car, especially underneath them. I've seen tons of hacked wire nutted connections fail on cars.

First, the wire itself. I highly recommend using "marine" grade wire. It is copper, but it is stranded pre-tinned (dipped in molten solder before the insulation is applied) so it has excellent corrosion resistant properties. (It also is easy to solder it that is your plan.) The multi-conductor versions are sheathed similar to NM-B.

Another source for marine wire http://www.genuinedealz.com/marine-wire.

I also recommend using convolute protective tubing. Finish the good quality PVC electrical tape (3M Scoth 88).

I agree with these two. I've been using GenuineDealz for years. They used to be dirt cheap. They have gotten closer to West Marine prices in the last few years, but their products and service are excellent.

I will disagree with American Locomotive on one point. Anyone who uses electrical tape on a wiring harness should have their hands removed. It invariable makes a sticky mess for the next person. Use wire ties, or better yet tie it like this. http://www.aeroelectric.com/articles/cable_lace/cable_lace.html
Lacing the harness is much cheaper and doesn't leave the razor sharp edges of cut cord ties.

 

[sberry]

Are we building a space shuttle?

 

[NUTTSGT]

Depending on what gauge of wire you're running and how many, there are many choices of trailer wire out there.

https://www.delcity.net/store/Trailer-Cable/p_820587

 

[gte718p]

Are we building a space shuttle?

Yes.

Why wouldn’t you build towards that level of quality. It costs nothing extra, adds five minutes to the project, and if you ever have to revisit it will save tons of frustration. In exchange for your five minutes, you have a quality product that will last.

I like to do a project once. Some people want to do things as fast and cheap as they can now, to help with the future. To each their own.

 

[Bert_]

I usually use MTW. I have lots of short pieces in different colors that are leftovers from 500' spools. It has fine stranding and the insulation is flexible.

The type of wire is far less important than the connections and how it is routed.

 

[Dumber than lumber]

I have used THHN in similar situations. Very tough outside coating. And then I use heatshrink tube where I have to to splices, or connectors.

 

[American Locomotive]

I agree with these two. I've been using GenuineDealz for years. They used to be dirt cheap. They have gotten closer to West Marine prices in the last few years, but their products and service are excellent.

I will disagree with American Locomotive on one point. Anyone who uses electrical tape on a wiring harness should have their hands removed. It invariable makes a sticky mess for the next person. Use wire ties, or better yet tie it like this. http://www.aeroelectric.com/articles/cable_lace/cable_lace.html
Lacing the harness is much cheaper and doesn't leave the razor sharp edges of cut cord ties.

You use a small bit of tape every foot or so to keep the bundle together, then you stuff it in plastic wire loom. That's what most factory harnesses do. It's cheap, quick and easy.

 

[gte718p]

You use a small bit of tape every foot or so to keep the bundle together, then you stuff it in plastic wire loom. That's what most factory harnesses do. It's cheap, quick and easy.

Most factory harness us harness tape. Slightly better then electrical tape, but not much. If you have to make a repair ten years down the road, it is a sticky mess.

I can actually tie a harness faster then I can tape one.

 

[toplessHO]

agree on the MTW
just say no to wire nuts
I fill all my heat shrink with hot glue BEFORE shrinking
altho Panduit and T&B both make excellent heat shrink with adhesive