SJTO or similar for underhood wiring?

you only need something that is 85°C or better for lighting. unless it's wired through a really hot part of the engine compartment.

strand count and strand gauge determine your flexibility, not so much insulation. you'd be surprised how inflexible insulation can become after a couple of decades of heat, yet the harnesses continue to do their job perfectly well.

but all this begs the question - why on earth are you skimping buying cheapo for something like this? what is your total saving? $2? just give yourself some reliability, buy some appropriately stranded 105°C online, all the color options you can imagine, and do it right. sheesh.

It's a lot more than that, unless I'm not looking in the right places. I just came back from the Hardware Sellin' Emporium (for other stuff, but I took a stroll through the electrical section since this idea was in my head) and I can get a quite long extension cord for $40-50; I dunno where to get automotive wire locally other than in those little blister packs which are silly expensive. If you know a good cheap source for wiring and supplies please do share!

The other funny thing is that a premade extension cord is apparently cheaper than the same amount of bulk wire... go figure?

nate

fry's? mouser? digikey? local radio ham store? ebay-milspec-by-the-foot? mcmaster? mscdirect? summit? jcwhitney?

my personal experience is that #4 will blow your socks off.

don't forget the heat shrink and a decent ratcheting crimp tool.

[decent crimp tools are crucial to reliable work. cheapo plier type are dismal. harbor freight is the best i've seen for a standard ratcheting crimper that's not priced to gouge.]

Why not buy wire that has sufficent specification from the bulk spools? Even the big chains like Lowes and Home depot sell (or sold) wire that will do the job this way. I got the wire I made the headlight relay harness out of at home depot. Gasoline and oil resistant printed right on the insulation. It's worked fine for years.

When I don't have a proper crimper I'll crimp and then solder the connection. Sometimes I solder the connection even if I have a proper crimper handy. Usually overkill, but it doesn't take long to wick a little solder in.

I have all the tools, just no local stores that sell the stuff. No fry's, no ham stores, just electrical supply houses. What keywords should I be looking for online?

The last time I did this I bought a premade kit that included wire; sadly, the gentleman that put out that kit is now deceased so that's not an option :(

nate

I was just looking at Lowe's today and all they had were a couple blister packs of "automotive primary wire" like you'd see at your FLAPS. No spools :(

nate

The spools are on a rotating rack and the wire is sold by the foot.

car harnesses don't use solder for a reason - and it's not economics. it's because crimped connections have much better fatigue resistance. the wicking causes a stress concentration - very unreliable.

all except the ham store are online and sell automotive spec wire. just go there.

OK, so what keywords? When searching online, I see stuff like "SAE J1128" and "GXL" but those are apparently not sold by the big guys (or I'm finding OEM sites that don't sell to the general public) how does that relate to something that, say, Digi-Key sells? that's the piece that I'm missing.

nate

Unless you're just doing simple fast-ons a generic crimper is never the right one and it does matter. Soldering in addition to crimping is different than just soldering. When just soldering the connection is fatigue limited by solder. If it is crimped and soldered, the crimp is making the bulk of the connection and prevents the relative motion that would break the solder.

solder wicking into the wire stranding creates a stress concentration that causes the wire to break, not the solder.

Well, if you're using the european-style connectors with the associated crimp tool that have the little fingers that dig into the insulation behind the crimp to the wire for strain relief, then soldering wouldn't seem to matter in that regard unless you really overdo it, and I'd be tempted to do it just for the added insurance.

nate

"Men occasionally stumble over the truth, but most of them pick themselves up and hurry off as if nothing had happened." Winston Churchill

that's it nate, just pick yourself up, and hurry off to your soldering. meanwhile the automotive and aerospace industries will continue to use unsoldered crimp connectors and can thus proceed reliably. enjoy.

No. SJ class cable is not designed for those temperature extremes or for really very good ability to handle oil and gasoline.

There are premade cables that are intended for those jobs; Belden makes a bunch of them in their industrial automation line.

--scott

Blah blah blah... at this point it is your word against an educated guess.

I've never had a single soldered connection fail, including some that I've done the "wrong" way. I know better now, but still.

nate

it's not very educated if you're ignoring the facts you're being presented. and it's not just "word" - simply open your eyes and look at your freakin' car's harness protocol.

and if you don't want to learn, at least don't tell other people they don't know what they're talking about - especially if you can't be freakin' bothered to dags. thanks.

"harness protocol?" you mean "the way it's put together?"

And aren't backstabbed receptacles still legal and more common than any other kind? are you going to argue that that's the best way to terminate a receptacle?

I just posited that with a strain relief the downside to a soldered connection that you presented became a non-issue. You haven't presented anything to the contrary.

Oh, and for someone who knows so much, you seem to be quite unwilling to answer the main question - which is, if oil-resistant extension cord cable is unsuitable, where *do* I find proper underhood wiring at a reasonable price? Everything that I'm coming up with is either manufacturer's web sites, 40-50 cents a foot for single wires (100' spools, shorter lengths are even more) or eBay ads that look like the stuff I find in Harbor Freight.

nate