TreeSeeker wrote:
Here is how to find wire guage.
You do need a micrometer. I do have one but I would need to cut a wire to measure it.
That's why I keep mine on the spool and only use odds & ends for jumpers and testing.
Figuring out what size wire is in a circuit is trickier, as you indicated. I try to figure out what size it is and go one size larger. (Slightly larger never hurt ... much larger doesn't hurt either but wastes money.)
Having said that, the size of heat shrink tubing needs to be at least as large as the outside diameter of the wire insulation. Two or three sizes larger, depending upon the size of the terminal crimp barrel or your splice. The neater your splice, the smaller the tubing can be, as long as the tubing fits over the splice.
The tubing shrink a lot so somewhat larger tubing will work.
BTW - I normally used uninsulated wire crimp terminals. I also solder the wire inside the terminal barrel after I crimp it. Final step is slide the tubing over the barrel and heat shrink it.
If I don't have uninsulated terminals, I strip the plastic 'insulation' off readily available terminals.
Also, heat shrink tubing, if it's an inch or so longer, serves as stress relief. (A double layer of tubing, if I think the wire will experience a lot of stress at the terminal.)
