Wire terminals

[enjenjo]

I am ordering some terminals and wire, and it occurred to me that most people aren't aware of what terminals we should be using.

There are several grades of terminals, the cheap ones just have a rolled barrel for the wire, and a piece of vinyl stuck over it for insulation. theses are in most cases junk, when you try to crimp them the barrel distorts, and the wire isn't secured properly. Futhermore, when there is vibration, the wire can fail next to the crimp.

The next grade up has a rolled body, with a thin tubular metal sleeve over it, and then the vinyl tube insulation. this is better than the lower grade terminals, the tube keeps the barrel from distorting as much, and acts as a strain relief for the wire, to help keep it from breaking next to the crimp.



The best grade terminals have a rolled and brazed body, with a molded nylon insulator. The brazed body makes an excellent crimp with little or no distortion of the body. The molded insulator has a molded in strain relief, that supports the wire next to the crimp.

Most of the mass market Bag-o-terminals are of the first type, most of the pasts store turntables have the second type. The best terminals are harder to find, although most manufacturers make them. NAPA stores stock the second type, but can order the best ones, it's a sperate section in the catalog. the only ones of the best type I see in the stores around here are Noble brand. I usually order them in bulk from Del City Wire, or Waytec Wire.

Insulated terminals should be crimped with a crimper with jaws like this (), not with the ones with a peg in one jaw. The peg type cuts the insulator, and may damage the wire if crimped too hard.

As far as soldering terminals, insulated terminals should not be soldered, if you are going to solder them, get uninsulated terminals, and insulate with shrink tube after soldering. I use only brazed barrel uninsulated terminals. Crimp lightly to hold them in place, heat the terminal, and apply just enough solder the fill the barrel. If the solder wicks into the wire beyond the barrel, the wire will likely break where the solder stops. Then shrink the insulation on. I will not use PVC heat shrink, it doesn't hold up well in areas with constant heat such as engine compartments. I use only Polyolefin shrink tube, where weather is a factor, I use dual wall polyolefin, which has an adhesive sealant on the inside. You can buy terminals with heat shrink already on them, over a nylon insulator, they work ok, but are kind of ugly when done.

You can also use uninsulated terminals, without soldering them, crimp in place, the peg type crimpers are made for this, and install shrink tube over the crimp.

Butt connectors should be avoided if possible, but if you must use them, use uninsulated, brazed barrel butt connectors with shrink tube over it. make sure the shrink tube is at least 1/2" past either end of the butt connector barrel for strain relief.  not only will this be a neater looking job, but you can inspect the crimps before installing the insulation.

[purplepickup]

....and if you're going to solder them, don't use acid flux...use rosin flux or rosin core solder.

[phat46]

There are several grades of terminals, the cheap ones just have a rolled barrel for the wire, and a piece of vinyl stuck over it for insulation. theses are in most cases junk, when you try to crimp them the barrel distorts, and the wire isn't secured properly. Futhermore, when there is vibration, the wire can fail next to the crimp.



  Well no wonder mine always fall apart. I really didn't know that there was different types. Thanks Frank, I'm about to start the final wiring on my truck project, i gonna go looking for the "good ones" today  

[Mac]

Really great info, especially considering the difference between an excellent and a poor job is only a couple `o bucks.

I nominate this post for TechOMatic...err I mean the Tech section.

[Crosley.In.AZ]

I guess I use the mid quality units the most.

I solder and use shrink tube on them.

[Dirk35]

I do the same a Crosley, soldier and shrink tube every connector. I have found its difficult (well I havent found it for sale in town yet at all) to find the shrink tubing with the glue inside. Luckily, my brother's shop uses it so I get it from him, but Id really like to find my own supply. None of the auto stores to Wal-Mart or Lowes sell the good shrink tubing.

Any suggestions? I honestly havent tried the electrical stores yet, and I really dont trust our Radio Shack.

[enjenjo]

Waytec Wire has it, and at a good price too. Also Del City Wire in OKC has it. We have a shop here in Toledo that specialises in wire, terminals, and connectors that carry it too.

[Skip]

There are several grades of terminals, the cheap ones just have a rolled barrel for the wire, and a piece of vinyl stuck over it for insulation. theses are in most cases junk, when you try to crimp them the barrel distorts, and the wire isn't secured properly. Futhermore, when there is vibration, the wire can fail next to the crimp.

That's because they're not properly crimped.

A proper crimp should create a mechanical connection on BOTH the wire and the insulation.

The insulation should be butted up against the wire barrel.

The wire barrel should be then crimped in a set of dies that TOTALLY surrounds the connector and, once the crimp is completed, an homogeneous mass of metal results.  Crimpers that dimple the connector will result in premature fractures at the point of contact due to the localized strain placed on the wire strands.

At the same time, a similar crimp needs to be completed around the insulation.  This insulation crimp creates a strain relief AWAY from the stripped end of the insulation where the connection is the weakest.

Soldering should not, for the most part, be used on automotive terminals except to seal the ends of the strands to the crimp connector.  When solder is allowed to wick down the strands, the connection becomes brittle and will soon fracture.

Solder terminals can and should be crimped prior to soldering the ends.  This provides a strong mechanical connection prior to the addition of the solder.  A heavy (dual wall) shrink tubing should be installed after the ends are soldered to provide the same strain relief action as the (far superior) plastic crimp connectors provide.

[Skip]

Then cover it with dual wall shrink tubing

[Mikej]

I have use the cheap connector for years and not had problems. When I use a butt connector, I use one big enough so I can bypass the stripped wires before I crimp them. The only time I have the wires break is if I crimp on the edge of the crimp sleeve. Granted, there are better ways and connectors but the cheaper ones will do for light loads.

[58Apache]

The way I look at it, I am putting in way too much time, effort, and money to not do the job the best I can. Especially when doing it right doesn't cost much more. I don't need problems at bad times at some point "down the road".

They do make special anti-wicking tools that grabs the wire after the terminal and sinks the heat out so that solder doesn't run up the wire. However, if you have enough hands, a pair of needle nose pliers will usually work. Small medical "hemostats" that lock in place also work well.

As for fluxes, even RMA flux has some amount of "activator" in it that's an acid base. I like to clean all connections with alcohol and a small brush.

There are professional crimping tools right? I wonder if one of you guys might show a pair and tell us where to buy them?

I was taught in my Nasa Spec soldering classes that  the proper way to make a connection is to first make a sound mechanical connection, and then solder with minimal solder, and then clean and inspect.

                                                   Steve

[Fat Cat]

There are professional crimping tools right? I wonder if one of you guys might show a pair and tell us where to buy them?

                                                   Steve

I have these



these



and these



All from snap on

[Skip]

For the money, you can't beat this crimper kit.  It comes with 5 sets of dies and will, also, accept the MSD spark plug wire dies.

It's made by Tool Aid and sells for around $64.

It crimps BOTH the wire barrel and insulation barrels in one operation.

[Skip]

I'll try and shoot a pic of my crimper collection and post it along with some terminal criomp shots

[MikeC]

Skip,
Who sells Tool Aid?  I have never heard of this brand.
MikeC