The crimp splices are used in a lot of places, including inside appliances. Usually with female spade connections to components such as switches and assorted modules. The wiring harnesses are made in advance and at assembly that’s the fastest way to make connections. Though I have seen some staked or punch down connections on occasion.
For automotive repairs if I’m using crimp butt splices I like the ones with clear heat shrink adhesive tubing built in. I can see I’ve got a good crimp and the heat shrink adhesive keeps out moisture. Be sure to use a good crimper with the correct dies
Class of 81. Yeah, you could take more shop, but when I went they had educational tracks and I was pre engineering so I didn’t have any electives to take shop past the first two years. I now have a woodshop in my garage. The drafting courses were pretty cool as well.
It was interesting. when I went to college and had to do my senior project, I’ll be honest, I wasn’t the best student. we needed a shaft designed and the really smart guy figured it would take a 3 inch shaft to turn this relatively light load. Having taken machine shop and knowing what a 3 inch hunk of steel looked like and felt like, I told him he was wrong. he looked at me with pity because obviously he was smarter than I. I told him to humor me and go over his calculations. He forgot a factor of pi. I think every engineer should have to manufacture something real before getting a degree.
For what it’s worth, schools still have drafting classes, except that it’s all CAD now. And shop classes have mostly moved into their own program, rather than general education: Around here, a student can go into the career tech track, and spend about half of their day on classes like automotive repair or construction (which may involve busing to a different school; not every school has the facilities).
In about 1997, I enrolled in a drafting (called mechanical drawing, I think?) class at community college. We were told that it would be the last time a pencil & straight edge class would be offered. I think the last few weeks were spent in the computer lab for an introduction to CAD.
I graduated in 1988 from RPI in mechanical engineering. We were never taught manual drafting but we did some CAD, using CATIA, I think. The workstation had a big CRT monitor and we used a lightpen. There may have been a graphics tablet, but I can’t remember. I do remember being told that we weren’t expected to actually draft in the real world, but instead be able to hand off a back-of-the-envelope sketch to a professional draftsman.
Was print shop a class at Lane, or just an activity?
My son studied Aero Eng. When he got his first job at ULA, doing quality control in a rocket plant, he said they appreciated that he had done a part-time job as a gopher for some friends who rebuilt old planes. Even tho a good part of it was cleaning up and handing tools, they said something about engineers who had no problem drawing things up w/ no thought as to how they would be built/serviced.
Back in the 70s at Lane, each student had to take (IIRC) 2 semesters of pencil drafting. had to buy a drafting board, pencils, T-square, triangles, etc. Lots of kids learned good printing - if nothing else!
I’m pretty sure I was on the science/math - pre college track, and I had to take 4 shop classes and 2 drafting.
Soldered wires (and other stuff) using a heavy iron heated in a gas stove in the 9th grade, this would be about 1966. We built a working electric motor (wish I still had it). And I own a house now where I have found soldered electrical wires in an outlet.
We had 4 semesters of drafting. Freshman year was basics, then sophomore year the drawings got more complex and the second semester was architectural drafting–culminating in “designing” your dream house (plans, elevation drawings, etc.–nothing structural)
I took a CAD course in college in 81. The “CAD” was actually programming a plotter to draw shapes, i.e. it wasn’t Ï need a circle here of X diameter" It was, “from center point x and y, go R distance and draw a line sin (360/n)” That was UIC’s version of a CAD course.
[quote=“jz78817, post:2, topic:917248, full:true”]
but for things like chassis wiring inside an appliance, or repairing automotive wiring, you’d definitely want to splice, solder, and shrink tube.
[/quote]Haven’t seen that for years, inside either an appliance or an automobile. All crimped connectors, or splices via crimped-on junctions, etc. I don’t think soldering is very much used at all any more – not very useful for automated wire assembly at all, and most such products are at least partly automated assembly now.
I’ve used both wire nuts and solder splices in residential wiring.
An example of the latter is when I installed ten, 4 foot light fixtures in the attic of my barn. The fixtures are butted against each other. (The barn is 40 feet long.)
I didn’t like the idea of daisy chaining so many fixtures with wire nuts. The current for the light fixture at the end, for example, would be going through 20 wire nuts. I didn’t like that.
So here’s what I did: I strung three, solid, 12 AWG wires from the first fixture to the last fixture (hot, neutral, and ground). At each fixture I scraped off about 1 inch of insulation from each wire and then soldered a splice to it and shrank HST around the joint. (While I was running the wires, I installed a piece of HST on each wire at each fixture.) The solder joints are much more reliable and have much less resistance than wire nuts. Has worked flawlessly over the past 10 years.
Would I recommend this to others? I dunno. I’ve been soldering for 45 years and (dare I say) have gotten pretty good at it. If you don’t have much experience in soldering I wouldn’t recommend it.
And while I’m at it, here is my procedure for using wiring nuts:
Make sure the wire nut is approved for the wire AWG and the quantity of wires.
Strip about 1 inch of insulation from each wire. Be careful not to nick the copper conductors when you do this.
Using a pair of duckbill pliers, tightly twist the copper conductors together.
Using a cable cutter, shorten the length of the twisted conductors to about 5/8 inch.
Twist on wire nut. Make sure it’s tight - keep twisting until it will no longer twist.
Wrap a cable tie around the bundle of wires adjacent to the wire nut. The cable tie should be in contact with the insulation of the wires. Don’t over-tighten the cable tie; just make it snug.
Wrap another cable tie around the bundle of wires about 0.5 inches away from the first cable tie. Again, don’t over-tighten; just slightly snug.
Here’s what I like about pre-twisting them: if the pre-twist is good and tight, then I would assume the primary current path is from strand-to-strand, not strand-to-nut-to-strand. With this approach, the nut is primarily a mechanical apparatus (not an electrical apparatus) that keeps the strands from untwisting, with the added bonus that some current can still flow through the metallic region of the nut. It also allows me to inspect the twisting of the strands (before the nut is twisted on) to ensure all strands are “equal.” I like that.
I twist, it’s easier to get the wires into the nut, I bet everyone does. But the manufacturers say don’t twist, and some electricians claim that they shouldn’t be twisted for some reason. I’ve never seen any official word but the general opinion is that the nut doesn’t make as much contact with each wire if they are twisted. If that is the case then I think it must be about the strength of the mechanical connection because there should still be plenty of contact between the wires.
I’m not completing twisting them like I’m making my own splice, I’m just twisting enough to make sure all the wires are staying together and won’t stick into the side when inserted, so I may be somewhere in the middle of the twisting spectrum.
The official word is that the NEC requires that manufacturer’s instructions be followed. If the manufacturer says don’t twist, then twisting is a code violation (not one that any inspector would ever catch).
I also put a slight (less than one turn) twist so that the wires stay together (more important with 4 or more wires nutted together). If I take the nut off later for rework, I notice that the physical act of tightening the wire nut has added additional twist.
I suspect it’s easier for the manufacturer to design a nut for “no twist” than to specify a minimum and maximum amount of twist allowed. Too much twist and the spring inside the nut might engage the wire are too shallow an angle to get a reliable connection.
I’m a twister. And… wire nuts have instructions???
Huh…a little web poking and some makers do have instructions. Whoodathunk?
Ideal, holder of the “Wire-Nut” trademark says “Pre-twisting acceptable, but not required.” 3M says “Firmly grasp wires, making sure insulation ends are even and tightly bundled. (Wires may be twisted or untwisted.)”
I have never seen electrical tape wrapped on a pigtail with a wire nut. I suppose it wouldn’t be harmful but if the splice is good and the nut is applied correctly it should be completely unnecessary.
