Thoughts on low-voltage, garden electrical connections

When you buy a kit or a single lamp for an existing system, you get this tiny plastic thing that’s gray and black, which is supposed to punch through your 12-gauge distribution line and hook up a lamp. I have had really poor success with this system and if you were to peer at the connections of the garden lighting in my front yard, you’d find black electricians’ tape and, underneath, solder.

(The general idea of tapping into the distribution line wherever you want with some sort of clamp-on device is good; the company actually sells a Bakelite version with a screw and nut that works well. It’s just expensive as hell; $3 each.)

So when it came time to distribute 12-volt electricity along my elevated backyard railroad, I had to come up with my own methods.

Initially, I decided to use telephone wiring blocks. These are now fairly difficult to find; most electronics and hardware stores (Radio Shack included) only sell the wiring block along with a modular jack mounted on the cover. In my application, the modular jack is superfluous, and the $5 for the combo is way too expensive. But when I started the 12-volt installation in 2003, they were still relatively easy to come by, so telephone wiring blocks were my first method.

In the 60-foot run around the layout, I installed four telephone wiring blocks — roughly every 15 feet — shorting out two of the four connectors. This gave me eight screw-down terminals.

As my passion to add structures and lamp-posts increased in 2007, it became clear that eight terminals per 15 feet wouldn’t be enough. At this writing, I have almost 30 devices that need connections to the 12-volt distribution line.

What I needed was a terminal strip that shorted out all the terminals. I haven’t been able to find such an animal, so I decided to make one myself.

Rather than buying terminal bridges (little pieces of metal that short out adjacent terminals on barrier strips), I take a four-, six-, eight- or 10-terminal barrier strip (see Radio Shack or Parts Express) and, using a Dremel, cut away the barriers. I then take a piece of 12-gauge stranded copper wire, tin it with solder and the butane torch, and cut it into pieces, each the width of the strip.

Placing the pieces of tinned wire between each of the terminals, I use the butane torch again to melt the solder and fuse the terminals together.

If I use a four-terminal strip, I make two of these, one for the positive lead and one for the negative; for the six-, eight- or 10-terminal strip, I leave the middle barrier in place and divide the polarity left and right (or up and down, depending up on the way it’s mounted).

Economically, it makes more sense to do one eight-terminal device rather than two four-terminal devices; at Radio Shack, the four-terminal costs about $2.40 and the eight-terminal costs about $2.70, which provides the greatest value (of course, I just checked eBay and there’s a guy selling six, six-terminal strips for $2 plus shipping, which of course is even better).

Each structure or lamp-post gets a spade terminal on each lead; I use 22-18 gauge wire studs, size 4-6. I have never acquired a spade-stud crimping tool; my Vice-Grip locking pliers, with the correct adjustment, seem to work fine.

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