Tonight I finished prepping cables for all the light circuits and branch circuits. I used Ancor Marine Grade 16 AWG duplex wire (red & black), which is a bit overkill but it will minimize voltage loss. I measured each circuit and rounded up to the next whole foot. There are a total of twelve LED lights in two banks of six. Each bank gets a dimmer switch. Each switch feeds into a six-way bus bar. And from the bus bar, each light gets a dedicated 12-volt circuit.

This is called parallel wiring. If they were daisy-chained in series, then each light would only get a fraction of the voltage it needs. I’ve read some bad reviews about these lights, but it’s because they weren’t wired correctly. And it doesn’t help that the instructions say to wire them in series — which is easier but wrong!

These cables, lights and switches are terminated with spade connectors, and this is what takes a lot of time. The male side (the spade) plugs into the female side (the slot), and this makes it possible to unplug parts of the system when maintaining the roof panels or adding new features to the cavities.

The Wirefy terminators I’m using come in various sizes and shapes, and of course I keep running out of the ones I need. For some reason it’s cheaper to buy an inefficient assortment than it is to order just the ones I need. And I just had to order my fourth set.

The termination process goes something like this:

1. Measure each cable from its spool, along a yardstick and cut it to length with heavy wire cutters.
2. Remove the vinyl sheathing from each end. This is something I had to learn and perfect. Basically I use a utility knife to score the sheathing all around, without hitting the insulated conductors inside. Then I use the blade to split the sheathing down the middle, toward the end. This makes a “tee” in the vinyl. And then it’s easy to peel the sheathing off the wires. Any other method will take much longer.
3. Strip each conductor to the proper length — with the proper tool. Mine is a Klein Tools Katapult, and it wasn’t cheap. For my terminators, that length is about 3/16″. Then make sure all the strands are together. If not, give them a gentle twist.
4. Place the terminator into the color-coded crimper divot. Not just any crimper, but a good one! Mine is made by Ancor, and again, it’s worth every penny. It has red, blue and yellow divots to help you pick the right size crimp. The color should match the color of the terminator’s vinyl jacket. Then gently ratchet the crimper down so it holds the empty terminator like a medical clamp. Make sure it doesn’t deform the collar yet, or you’ll ruin it.
5. Carefully insert the bare copper into the terminator and visually inspect it. Most of the time it’ll twist right in, but sometimes you have to fiddle with it. Be patient, and gentle.
6. While making sure nothing slips, squeeze the hell out of the crimper handles. I can’t seem to do this without clenching my teeth too. My jaw muscles must be wired to my Kung Fu Grip muscles.
7. The crimper ratchet is designed to release once you’ve exerted the proper pressure, at which point the jaws will release the terminator.
8. Now inspect the terminator with a gentle tug. You don’t want to pull the copper out of the collar, you only want to confirm that it doesn’t slip.
9. Repeat for the other conductor (or two more if you’re using triplex cable).
10. And finally, break out your heat gun and carefully melt each terminator’s vinyl jacket so that you can’t see any air bubbles.  You’ll have to watch closely and roll the cable between your fingers to apply even heat. This step serves two purposes: The inside of the vinyl jacket acts like an adhesive, which keeps everything stuck together. Enough, in fact, to compensate for a marginal crimp. And of course it also adds some protection against moisture, considering how you’ve removed the cable’s sheathing to make this termination possible.