Dirk- Did you run one 12ga line and then use some type of connection you get on a Home Depot light? The kind that taps in to the power line? Or did you run power to a light, make up a pigtail for the fixture and then splice in power to the next fixture? So- at each splice - power in, power power out and power to fixture?
I don't know what you get with a HD light, but if it's something you just clamp onto a wire, and it stabs thought the wire's jacket, then no, those are junk and will quickly fail.
The Volt lights can be ordered with 4' or 25' pigtails, 14G I think. They are sealed into the brass fixture. Stripped wire on the other end.
Then you get a 12G main line, which wires to the transformer. I put my transformer, which is in a watertight box, inside a second, bigger watertight box, along with some Home Automation switches. I ran the wires out of the box, through PVC legs that sink into the dirt, hoping that extra step would help keep bugs and spiders from finding their way into the box.
The mainline snakes around the yard, to pass within range of each fixture. I passed the line pretty close to the fixture, so once spliced in, the fixture could be moved around in that 4' radius circle to adjust its coverage and/or affect on the plants or deck.
At each splice, I cut and stripped the main line, and soldered two sets of three copper, stranded wires together. This requires a medium-to-heavy duty soldering iron, because soldering three big stranded wires together needs a good bit of heat.
Then I screwed the waterproof "goo-wire-nuts" onto/over the solder joint. The nuts do help make a secondary, backup electrical connection, but primarily the solder is doing that, permanently and waterproof. The nuts keep the bare wires from coming into contact with water or moist soil.
A also strategically placed several big loops of the mainline around the yard, so I'd have some slack to adjust its path. And then I zip-tied the mainline and pigtails nice and neat, usually attaching them to the existing irrigation drip line. The logic there was, now that the connections are bulletproof, the next failure point is me driving a shovel through the line! I figured if it was strapped to the drip tubing, I'd be less likely to forget where it was, and less likely to accidentally slice it in half.
Some of the lights screw into the plastic stakes that Volt sells. They also sell brass risers of various lengths, but I made my own out of electrical PVC. I spray painted them to match the brass, but could have left them grey. Both the fixtures and risers tend to visually fade into the landscaping pretty well. The brass develops a patina that disguises it further, they don't stay their original color for long. That didn't bother me. I suppose you could coat them with something if you wanted to preserve the color. While technically tha patina is a type of corrosion, the lights are not made out of sheet metal. They are cast brass, and quite heavy. I can't even guess how many years it would take for them to break down. I have many that are in the path of sprinklers, which I'm not concerned about at all.
