Practical & Philosophic questions: Landscape Lighting

[Tinkerer]

Recently, I have been installing a lot of landscape lighting for folks who have bought their lights (typically Malibu) from the nearby discount hardware chain. I am OK with this, since I don't mark up my own supplies very much, I don't need to get involved with the artistic side of the selection process, and I don't need to warantee the fixtures.

I don't think much of the method Malibu recommends in their instructions, with screw together connector boxs, landscape wire that costs as much as UF, and an expensive outside transformer that has a lot of unnecessary complicated features the customer doesn't need. Malibu says burial of the cable is optional, but should be LESS than 6 inches deep.

My experience with my own outside lighting, is that every time I plant something near it, it gets cut, so this is my ideal installation: Run the lights in PVC pipe, buried MORE than 6" deep. with something like THHW inside, no ground, and run the pipe right into the lights. The transformer would be a simple indoor type, mounted indoors. This would be a Chapter 3 wiring method which would be acceptable to the NEC for outside, inside, and concealed applications (see I read the other posts about this subject). I have used "T" type conduit bodies to "T" up to each light, but I believe this is unacceptable because of article 314.29, requiring conduit bodies to be accessible. My questions are these:

1) Is there a PVC conduit body that allows two pipes to be stubbed up, and connected to the fixture? This would be something like a tiny box that wouldn't look bad with some mulch pushed up against it.

2) Does anyone have another clever, attractive way to run pipe directly to the fixtures.

3) Here is the philosophical question: Why exactly did the industry settle on 12V for low voltage lighting? Indeed, what is the advantage of Low voltage over 120 V wiring. It isn't cheaper. The risk of fire isn't reduced. Even 24 V or 30 V would be superior from a power-wire size point of view.

Doug

 

[brantmacga]

I don't know of any such fittings you describe.

All of those cheap fixtures i've installed were attached to a spike, and only had a two-wire zip cord lead hanging out the back; not really a fitting to a attach it to a box anyway.

I install them per the directions; I think they're trying to make them easy to remove when they stop working in 6/mo.


As for the 12v; I have no idea why they settled on 12v versus 24v.

But the reason the make the fixtures LV is because they are designed and marketed to homeowners and under the assumption they will be installed by homeowners. Most HO's specifically look for LV fixtures because they are not interested in working w/ 120v+. Think how many customers you have that tell you they are scared of electricity.

 

[tom baker]

Landscape lighting (per article 411) is designed as a system. What you describe in using pipe/wire per Article 300 I belive would be allowed, but I am not sure, it may depend on how the lights are listed to be installed.

 

[wireguru]

I just redid the lighting in my back yard. I tore out all the malibu crap and went with line voltage fixtures. I wanted something that would last 20 years, and I am sick of the replacement lamp costs, failing sockets, fixtures that decide to fall apart, etc for the malibu lights.

I used red dot fixtures (3 tier, and spotlight). These fixtures sit on a post that looks like 2in ABS. You stub the pvc conduit right up into this post, make the connections up and the fixture site right on top of it. I needed fewer of them, ex one 3 tier with a 15w lamp in it is lighting the same area that previously had 3 malibu lights. 6 malibu spotlights was replaced by two. I used 15w 130v lamps in the 3 tier, and 35w 130v R20 in the spotlights. Another nice thing about these fixtures is they are sealed and dont get all full of dirt, spiderwebs, and bugs like the malibu lights do.

I figured the cost and after considering 1/2in pvc, #14thhn and the fixtures, it was actually cheaper than the malibu lights, wire, and transformer it replaced.

 

[Pierre C Belarge]

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I used red dot fixtures (3 tier, and spotlight). These fixtures sit on a post that looks like 2in ABS. You stub the pvc conduit right up into this post, make the connections up and the fixture site right on top of it.
I figured the cost and after considering 1/2in pvc, #14thhn and the fixtures, it was actually cheaper than the malibu lights, wire, and transformer it replaced.

Around here, we call them "Rocket posts". This is exactly what I was going to mention.

 

[zbang]

Just guessing.... 12v system because 12v lamps (automotive) are common as dirt and the lamp manufacturers make -lots- of them, and even if the emvelope is different, the filiment is the same.

 

[wireguru]

Around here, we call them "Rocket posts". This is exactly what I was going to mention.

ive seen some with 'fins' on them. These that came with the reddot fixtures are just a straight tube.

Arlington makes a square version with a singlegang device mount on each side, but with bubble covers on them theyre too commercial looking for most residential.

 

[wireguru]

Just guessing.... 12v system because 12v lamps (automotive) are common as dirt and the lamp manufacturers make -lots- of them, and even if the emvelope is different, the filiment is the same.

I actually think there are some automotive lamps that cross to malibu lamps.

 

[sparrott4]

Recently, I have been installing a lot of landscape lighting for folks who have bought their lights (typically Malibu) from the nearby discount hardware chain. I am OK with this, since I don't mark up my own supplies very much, I don't need to get involved with the artistic side of the selection process, and I don't need to warantee the fixtures.

It's hard to understand why, since you are a professional, that you would knowingly install such poor-quality products. You're really not providing a valuable service to the homeowner. Why not purchase and install high quality lighting fixtures - they can last the lifetime of the home instead of failing after one or two years (like Malibu).

Run the lights in PVC pipe, buried MORE than 6" deep. with something like THHW inside, no ground, and run the pipe right into the lights.

If you use quality and rated outdoor lighting cable (#10/2 or #12/2), you're fine burying the cable 6" (per NEC) throughout the property, the only places you need conduit are in areas likely to be disturbed by landscape work. It's often required to move lighting fixtures as plant material grows so you don't want to get tied into a location with a fixed conduit. Leave a coil of wire buried near the fixture so it can be moved later.

3) Here is the philosophical question: Why exactly did the industry settle on 12V for low voltage lighting?

The LVL industry did grow out of the automotive industry. In fact, the very first experimental systems used car batteries to power the lights. The ready availabilty of a wide range of bright 12V automotive lamps, and the extensive and ongoing R&D on the lamps have given LVL mfgs. a great deal of flexibility and control in the design of the fixtures.

Indeed, what is the advantage of Low voltage over 120 V wiring. It isn't cheaper.

True, the wire's not cheaper, but 12V systems are cheaper to install (less conduit, less labor) and cheaper to operate (more energy efficient and lower wattage lamps can be used).

The risk of fire isn't reduced.

Not true, higher wattage lamps pose greater risk of fire. Typical 12V lamps are 10W to 50W. Typical 120V lamps are 50W and above.

And, of course, the risk of dangerous electric shock is high with 120V and non-existant with 12V.

Even 24 V or 30 V would be superior from a power-wire size point of view.

True, there is less voltage loss and you can use thinner wire with 24V or 30V vs. 12V, but the industry has been built around 12V; there are many problems associated with trying to build and maintain professional lighting systems at these odd ball voltages.