A few weeks ago, I read an article in an influential national newspaper about the value of adding lighting to residential outdoor spaces. In the story, a designer talked of the ease of installation and reiterated a common misconception about covering low-voltage wire under only mulch. That flaw in information made me rethink the belief that low-voltage landscape lighting was a viable DIY project. Despite its perceived simplicity, there are many things that make it more complex and a professional might be a better option.
Wire Burial
In a low voltage system, more heat is created when compared with traditional 120V wiring. Because of that, the wire is a larger gauge with thicker insulation. Mulch is simply dried wood. If the wire were covered by mulch, the heat would build and eventually, the heat would ignite the mulch, first smoldering, then turning to flame. Soil serves as an insulator. Burying this wire in 6” of earth provides the additional heat protection needed for safe operation.
Wire and Amps
A transformer in a low-voltage lighting systems contains a breaker that provides electrical protection from overheating. Its protection is based on an amperage maximum. When the breaker experiences “activity” in the system in excess of that amount, it trips, thereby protecting the system from damage. Wire also contains an amp rating. The wire selected must be of an equal or greater amp rating as the breaker in the transformer. Failure to do so, could result in wire overheating before the transformer senses a problem. A professional landscape lighting designer/installer will understand the importance of balancing the protections provided by both the wire and the transformer’s breaker.
Wire Connectors
Like the transformer and the wire, wire connectors are UL listed/CSA certified and serve as a key link in the electric chain created in a low-voltage lighting system. Using an inappropriate connector in the wrong way can also result in electric failure.
Wire connectors are rated and tested for a very specific collection of wire combinations. People might select a connector based on color or what appears to be “big enough”, but proper choice is much more involved. A typical trunk line, the wire that travels from the transformer to the lighting fixture is 12 gauge wire. Most luminaires employ 18 gauge wire. That means the wire connector must be rated to connect one 18 gauge and one or two 12 gauge wires. On the back of the carton, in very small type, all of the various connections are listed. It is important to insure that the connection intended is included in the list. If not, the liability falls to the installer, not the connector manufacturer.
Wire used in low-voltage landscape lighting must also be rated for “direct burial.” This usually means it is gel-filled. As the wire enters the connector and it is turned clockwise, the gel surrounds the copper strands and seeps out the bottom fully encapsulating the connection. Furthermore, the connector must also be properly turned and tightened onto the wires or another problem, electrical arcing, will occur.
Watts vs. Volt-Amps
In an incandescent world, understanding the capacity of a transformer was easy. Add up the wattage consumption and don’t exceed the output. LEDs are different. A factor must be included to compensate for the different way in which the LED uses electricity. For LED systems, the installer must use the volt-amp (VA) number provided. For example, a lamp might use only 4.5 watts of energy to provide light, but the VA is 6.1. 6.1 must be used to properly calculate the load capacity for the transformer.
Design Expertise
Perhaps the most important reason to contact a professional landscape lighting designer is the expertise they hold. Many do-it-yourselfers are talented folks, but residential landscape lighting is an unusual skill. Heightening the look of a residence, the outdoor living area and/or the gardens takes an artistic understanding that is grown year over year. Through experience, they know what works on certain trees and what doesn’t on other plants. They have learned how to properly illuminate a walkway, eating area and a deck. While the safety aspect is very important, it can be learned. The design skills polished over a career are less transferable.
Low Tech vs. LED
In the days of incandescent low-voltage landscape lighting, the entire process of balancing the electric load to deliver a consistent output was VERY complicated. Even some of the younger professionals had a difficult time learning this technique. Since low-voltage landscape lighting has become an LED business, that skill is thankfully, no longer required. The systems however remain an electric connection and all of the other safety precautions must still be maintained. Couple this with the needed design skills and the answer to my question is probably, “No.” To get a great outdoor lighting look, installed properly, you should call a professional. You’ll be happy you did…and you won’t have a fire in your flower bed, either!
Lighting by Jeffrey 