There are many different kinds of tape. Because people use tape for many many different things.
Knowing what you want to do with tape is the key to using the right tape. Are you trying to hold something together? Or mask something off? Hang something up? Or stick something down? All different kinds of tape. So here’s a post about one kind of tape, and there will be more posts about other kinds of tape.
You need this if you are doing any sort of electrical work. It’s vinyl, usually 3/4″ wide, and usually black. You use it to cover any sort of electrical joint to keep it insulated. Many electricians will wrap a layer of tape around the outlet or switch after the wires are connected to keep the screws from shorting to anything else in the box. And usually around the base of all the wire nuts to keep them twisted on and extra safe.
When you go to the Big Box Home Center, you will find that there are a few different brands of cheap black electrical tape, including 3m’s budget line.
I hate them all.
The adhesive on black electrical tape is black. And it doesn’t stay on the tape. So if you have to go back in for anything there’s black goo everywhere, even after just a few days.
The adhesive on 3m’s more expensive colored electrical tape is not black. And it stays on the tape mostly. This is the stuff I generally buy. It comes in 9 colors. If you buy more than one color you can also use it to help remember which wire is which.
(There are historical reason why it comes in 10 colors (including black), having to do with the history of telephones:
Every phone line needs a pair of wires. And a phone cable might have many many pairs of wires inside. So how do you tell them apart? Color coding! Ma Bell came up with a system of color coding in the 40s that lets 10 colors sort out a virtually infinite number of wires. The ten colors are divided into 5 “tip” colors (White, Red, Black, Yellow, and Violet), and 5 “ring” colors (Blue, Orange, Green, Brown, and Gray (Called “Slate” so that each color in the group of 5 has a unique one-or-two-letter abbreviation: W,R,BK,Y,V, BL,O,G,BR,S). So a pair of wires will consist of a wire that is mostly a tip color, with stripes of a ring color, and its other half which is mostly the ring color with a stripe of the tip color. For instance Yellow with Slate and Slate with Yellow. And the pairs are thus in numerical order from White/Blue all the way to Violet/Slate. And once you know the code, you can figure out that the Yellow/Slate pair is pair number 20.
So that gets us up to 25 pairs (5×5). After that, you wrap that 25 pairs in…a White and Blue string! The next 25 pairs are wrapped in a White and Orange string. Etc. So that gets us up to 25×25, which is 625 pairs, or 1250 individual wires. But to make the math easier, they stop at 25×24: 600 pairs. You can go on from there, wrapping that whole bundle in a white and blue string. And so on. But it’s already ridiculous…In any case, that’s why the electrical tape comes in those particular 10 colors: so that phone people can use it to mark things in a standardized way.) (incidentally, that’s also why phone company boxes and stuff are that special greenish gray: that color is not Slate. So things like zip ties and the like that are that color are not mistaken for color-coding markers…)
Electricians use a different color coding scheme; theirs is all about what’s on the wire rather than which particular wire it is. But that’s not relevant; electricians mostly don’t pay attention to the color of the tape. They mostly use black. But as I said I don’t like the black because it tends to leave its goo everywhere. I buy a different color roll every time I buy some.
Electrical tape tends to get stiff after a few years (especially the cheap stuff), and it doesn’t stick very well to things that are not metal or plastic. So it’s not good for doing things like taping up packages. But you need some around if you are ever going to do electrical work.
When taping over a splice, use enough. You should start a little ways back from the joint, and wrap it around and around, layering about half the width of the tape each time so at every spot on the repair there is at least two layers of tape. On the other hand, it’s certainly possible to use a stupid amount of tape and make a repair that is no safer than the right amount of tape, and may be less safe just by being a bigger lump to snag on things. Use prudence.