On Jul 25, 4:59*pm, David Nebenzahl wrote:
Got a client with an outdoor low-voltage lighting system in need of
repair. Basically just 7 surface-mount lights on a stairway outside.
It's currently wired with some kind of zip cord, which may or may not be
the right stuff. (Looks like 12-14 ga.) Here's what I'm proposing to do:
Tear out most or all of the existing wiring, which is partially buried,
partially above ground. Using the existing fixtures where possible (see
below), rewire using new wire of the correct type, burying cable as needed.
What I'm not sure about is the following:
1. Correct type of cable to use:
Checked at Home Despot, which sells something identified as "landscape
lighting cable" in the form of 2-conductor zip cord, black, in several
gauges. I'll probably use 12, as the run is less than 200' total, and
voltage drop isn't currently an issue (when the system was working, all
lights were equally bright).
Is this stuff OK to use outside? Two issues I can think of: buriabilty
and resistance to sunlight. Parts of the existing wiring have
deteriorated to the point of shorting out.
I understand from some online sources (like this one:http://www.iaei.org/magazine/?p=2290) that what I should be looking for
is type SPT-3 cable. Is that right? According to this article, it needs
to be buried 6" (except under driveways and such, which isn't an issue
here).
I realize I could use UF for this project, but that would be more
difficult for several reasons, and much more expensive (UF is about
twice the cost of the zip cord for the same gauge). So I think I want to
stick with the zip-cord stuff. With UF, I'd either have to use junction
boxes at each light, or figure out some Rube Goldberg way of connecting
the lamps to the UF.
2. Connections:
The replacement lights I've looked at all have what I consider to be
cheesy connectors on them, the type that stab into the cable and pierce
the insulation. Not much better than those quick plugs that squeeze down
* on the cord and pierce it.
So I'm planning on going either with wire-nut connections or soldered
connections. I'm thinking that soldering, which probably the best
solution, is probably overkill, and makes later maintenance more
difficult. So it seems to me that a good wire-nutted connection, wrapped
in lots of electrical tape to keep out moisture, would be acceptable.
3. Light fixtures:
Currently the fixtures are those little round surface-mount ones that
take a 7-watt halogen bulb, made of plastic. These appear to be all
that's available today, at least easily: on a recent grueling research
trip I visited both Orchard and Home Despot, which both have those
Malibu units. Home Despot wins here because they also have these in
metal instead of plastic. However, the metal ones aren't really much
better, because in all of these fixtures, the weak point is the lamp
socket, which appears to be identical in all types, just a simple
push-in type of socket.
If anyone knows of better fixtures (that don't cost an arm and a leg),
I'd appreciate knowing of them. These ones can be had for about $12 for
the metal ones.
And no, the homeowners don't want different lights, like those
upward-pointing ones or ones on stakes on the ground.
--
The fashion in killing has an insouciant, flirty style this spring,
with the flaunting of well-defined muscle, wrapped in flags.
- Comment from an article on Antiwar.com (http://antiwar.com)
The black 12ga cord is what they all use. It's fine. The stab
connectors are ok for a while but do eventually corrode. Moving them
to another spot on the wire fixes that. A better connection would
last longer but is more work. Don't bury the connections if at all
possible. Most of the light fixtures have a way to loop the cord
inside the fixture so you do no thave to bury the connection.