Wiring splices

When I was in high school, everyone had to take electrical shop. The first project was wiring splices. there were about 6 including the standard pig tail. You made the splice, then you had to solder the splice. You couldn’t just clump the solder on it was almost like a plating. you needed to be able to see each individual turn of the wire–so it almost looked like paint on the splice.

I’ve never seen this in real life. Maybe the advent of wire nuts made this method obsolete, but wire nuts were invented in 1946 and I was in high school in 1977. I’ve lived in some pretty old houses and don’t remember ever seeing soldered wire splices. Were they ever a real thing and if so, when did they go out of fashion?

wire nuts are the go-to for residential wiring, but for things like chassis wiring inside an appliance, or repairing automotive wiring, you’d definitely want to splice, solder, and shrink tube.

There are several reasons.

It’s very easy to make a bad solder joint, as noted in the OP. A cold solder joint (just blobbing the solder on) will eventually fail and is a very bad thing.

Wire nuts are faster and easier to install.

Wire nuts make things easier from a maintenance point of view. If you need to remove the splice, just undo the wire nut, replace the part that needs replacing, and use the wire nut to splice things back together again. Easy peasy.

I personally have never seen soldered connections in residential wiring. Wire nuts are definitely the way to go.

Solder splices are common elsewhere, as jz78817 mentioned. But you don’t want to use them in residential wiring.

I have seen solder splices in industrial wiring, but they were in I/O communication cables and were specifically there because they didn’t want anyone to break the main trunk line connection if they were taking a node on the line out of service, so it was easy to disconnect the device from its drop cable but was difficult to disconnect the splice where the drop cable joined to the main trunk line.

especially with solid core wire.

It seems weird for a high school shop teacher to require that every student learn how to do that. I think most will just need to know how to use wire nuts for minor electrical work at home. Soldering skills might be helpful for minor household plumbing repairs, though.

Depends how old you are. If they had a specific ‘Electrical Shop’ class they’d probably put this in. It wouldn’t come up in household wiring often but if you were trying to repair an appliance (something we actually did back before color was invented and the world was still in B&W) this would come up because stuff was made out of wires and big pieces of metal and not just circuit boards.

If the kids ever go back to school the only ‘Shop’ class might be something to do with shopping online or something like that.

That could be the reason. It’s also the case that every teacher (and really every person) has their own idea of what students need to learn in school. For some reason, that shop teacher felt that wire soldering was important for his/her students.

Yes, and the shop teacher might have made that decision 20 or more years before the OP took the class.

I’m 39 and never took any kind of shop classes. I learned a little bit about residential wiring from my dad, who always used wire nuts that were then wrapped in electrical tape for splicing Romex.

My uncle, a lifelong farmer, taught me a little bit about car electrical wiring, and he swore by these type of connectors:


(As an aside, does anyone have any opinion on these? I haven’t had to re-wire anything automotive in years, but I still have a box of those connectors buried in the garage somewhere.)

6 months or so ago I taught myself how to solder. I spent an afternoon watching youtube videos, made a list, hied myself down to the hardware store, and picked up all the shiny toys and accessories. A friend had given me an old tacky tension pole lamp from the 60’s that I wanted to actually use, so I had to rewire it. It was easy and surprisingly kind of fun. Some flux, hot solder, and each connection covered in shrink tubing and I was in business.

Anyway, I guess the point I’m trying to make is that learning about basic electrical connections, including soldering as well as using wire nuts, is important for a kid to know – and its just as important for a kid to know what application is best used where.

The set you linked to has a bunch of different types of connectors in there. Since we’re talking about splices though I’ll assume you are referring to the crimp-style butt connectors in there.

Butt splices are good in that they install quickly and easily. Everything in that set is a crimp connector so the crimping applies to all of them. The advantage over solder is that the crimp connection won’t weaken or break due to vibration or thermal expansion and contraction, assuming of course that you have a proper crimp on it. The disadvantage of crimps in butt connectors is that it’s difficult to see if you have a good crimp or not. With some of the other connector types you can look in the other end and see if you have a good crimp or not so it’s not as much of an issue. The butt connector also isn’t the strongest type of splice if something pulls on the wires. The wire can pull out of a crimp a lot more easily than it can pull out of a wire nut or a wire that has been twisted together and soldered.

Yeah, the little tubes that you slip each wire into and then crimp with a pair of pliers or the special teeth of a wire stripper. I tried to embed a picture of the butt connectors, but I guess we can’t do that. My uncle also like to use the little male / female spade connectors in auto wiring.

Personally, now that I know a bit about soldering, I’ll likely use that method instead of butt connectors from now on. In the past I have had butt connectors and spade connectors fail – like you say, they pull apart easily if not done right.

Hey - did we go to the same school? :smiley:

I only remember 3 - but the only other one I remember was the Western Union. I thought it had a diff name.

I’ve used both the pigtail and Western Union as a homeowner. Even if you don’t solder and tape, don’t you pigtail before using the nut?

That sort of splice is definitely not something that you would do with house or premises wiring. I suspect that the shop classes you guys are describing (at least the soldering parts) were teaching electronics technician skills, not electrician skills. As implied in other posts, the techniques in the two fields are different.

No, man, this was HS shop class.

I took electric shop, woodworking 1 and 2, foundry, and auto repair.

I haven’t used that W-U in some time - ISTR splicing a cord such as on a lamp or an extension cord. It is a very sturdy splice. Why would you NOT use it? We also made a small working electric motor, windings, brushes, etc.

Here’s another link - calling it a lineman’s splice. Works fine if you don’t want the pigtail and nut.

Of course, back in the 70s we didn’t have to waste time on computer skills! :smiley:

Perhaps the point was just learning to solder, and the choice of doing it on wire to wire joints was cheaper than soldering to components? A couple inches of wire is cheaper than just about anything else you could try to solder to.

I think that learning to solder two copper pipes would be almost as cheap and probably more useful than soldering two wires.

given you took foundry, probably. Lane Tech in Chicago. all 1500 classmates had to take Electrical and wood shop freshman year and everyone had to do the splices. There were six. My electrical shop teacher was a young guy so this wasn’t someone stuck in his ways. Sophomore year you had more leeway–you could take machine shop, foundry, auto shop and there was one more, but I can’t remember what it was. Machine shop was cool. Auto shop depended on the teacher. everyone else learned how to do brakes, a tune-up, break down an engine. I had a miserable POS who taught nothing useful (and he used to sleep in the shop). I’m have a masters of engineering and to this day I’m afraid to touch my brakes.

I have run into soldered pigtails in house wiring - the house was first wired in the 40s, so it was from the very early days of what we’d think of as normal wiring, vs knob and tube. Wires twisted together, soldered, then wrapped with a blob of friction tape. Each splice was about as big as the end of my thumb.

AFAIK, wire nuts (marrettes to our Canadian friends) didn’t see common use until the 50s, and the early ones were ceramic.

As for twisting before screwing on a wire nut - absolutely! You want to be sure of a secure mechanical connection before hiding it under a wire nut. I’ve seen far too many failed splices where one of the wires was only making contact through spring tension of the wire holding it against its mates.

why would pipe soldering be useful for an electrical shop class?

Ha! Class of 78! (My dad was '38.)

Not sure if it is what you were thinking of, but I took a 2d yr of woodshop. And they used to have an aviation shop - we ran across an old airplane exploring the basements. And I forgot the 2 yrs of drafting. Now THERE’S a good liberal arts education for ya! :smiley: