I will admit that I haven't done it, but I have a basic understanding of AC-electricity, watched a youtube video that went over that, and I stayed at a Holiday Inn Express last night...lol You can get on youtube and watch videos also....just search: "install heat tape"
Basically, each piece of heattape has 2 "terminals". Lets call it A-side and B-side.
For 1 strip of heat tape, you hook 1 wire to A, and 1 wire to B. Now, using appropiate lengths of 2-wire electric cord.......connect 1 of the wires to shelf1 on the A-side and run it straight up (or down) to the next shelf.....connect this wire to the A-connector on that shelf. Then connect wire2 to the B-side of shelf1.....connect this wire to the B-side on the next shelf.
It will be wired like this:
A-A-A-A-a----\
B-B-B-B-B----/ 2-wire wall plug.
(Each "dash" is wiring)
confirm this by watching youtube videos, and only attempt if you feel comfortable and understand what you are doing. This is what I remembered from the videos and it makes sense when it comes to AC-electricity. The current will always reach one side of the heat tape, travel through (and heat) the tape, and return on the other-side.
I havent had a need to splice individual pieces together. Ive always routed out the slats in a way to make it one continual piece that snakes up and through to the subsequent levels. Always seemed easier than cutting, and wiring, and drilling etc.