Materials - Components
Landscape Lighting System
Table of Contents
Low Voltage Transformer
Line voltage AC to low voltage DC power supply for the lights.
Choose the right kind and size transformer
Indoor and or outdoor mounting. Power output rating in watts.
- Choose Transformer Size
Transformer size rating is power output measured in watts.
Add together the wattage of your individual lights
Multiply that total by 1.5
The new total is a safe transformer size, in watts. Any upgrades aside. Add future lights! Plan Ahead? Yes. Keep in mind, much of the it is more convenient to add a second transformer. Wire runs to separate areas is planning that keeps a lighting job more simple and expandable
Considerations For Transformer Location
- The transformer can be mounted inside or out. It is easier to mount near a receptacle.
- The transformer needs an 120v AC outlet to plug into.
- The transformer needs to be mounted above ground at least 12". Higher if outdoors and where snow may pile up.
- If a photocell is mounted to the transformer, the photocell needs to see light level changes.
- Landscape light wire will run between the transformer and fixtures.
Choose a location which will be above and away from as much snow and rain as possible. The location will require access to AC line voltage as a power source. Transformers are available direct wire. Most common locations are in the garage, on a post, under the roof eve. Garage mounting requires a hole drilled for wire cable entry. An outdoor shed with power available can be an ideal location. Lights location is a consideration for transformer location.
Features to look for in transformer selection.The transformer below is typical of modern low voltage power supply's (transformer with features). A useful feature is the remote photo cell. The photo cell is attached to a 60 inch wire which makes it easier to place for better sensing light/dark.
Malibu 200 Watt Power Pack with Sensor and Weather Shield for Low Voltage Landscape Lighting Spotlight Outdoor Transformer 120V Input 12V Output.
Direct burial low voltage landscape wire.
Flat-Twin Bare COPPER Wire connects in transformer and supplies power to the lighting fixtures. The wire is rated according to the size of its conductors. Selecting the proper size wire is one of the most important aspects of the lighting plan.
The wire from the transformer needs to connect to the wires at the light fixtures. These connections can be made in several ways that involve any of various connector types. 14/2 Low Voltage Outdoor Landscape Lighting Wire, 100-Feet
100 ft. - 12/2 Low Voltage Landscape Lighting Wire - 150 Volt Max. - PLT CLV-1202-0-100FT
Voltage Drop and Wiring Methods
Every lighting job and every lighting system are the same, right? Well, not quite. The wiring method used can affect both system performance and, more importantly, the visual outcome (the lighting portrait). We will compare the most common wiring methods below, but before we do that, let’s consider the nemesis of wiring any landscape lighting system: voltage drop.
Power loss occurs from watts used by lights, some loss is from wire resistance. Power loss on the wire; Voltage drops as wattage increases.
Light Fixtures / LED Bulbs (lamps)
These are, of course, the producers of light. They get their power from the transformer. Each lighting fixture contains a light source - either an integrated (built-in) LED source or a replaceable lamp (bulb). The lamp could be the older incandescent (usually halogen) type or it could be an LED lamp. The voltage supplied to the fixtures is critical and we will discuss that later.
Light Fixture and Lamp Output Selection
Lots of lighting fixtures are available for outdoor low voltage installs. Most of the low cost fixtures work very well.
Typical install includes a combination of up lights, flood lights, path and area lights. We use LEDs for all our install and repair. 5 to 7 watt LED replaces a 50 watt MR16 halogen, and even brighter. The newer LED retrofit lamps are available in warm, cool, daylight etc. They are available in all the regular beam angles. Even the newer 5 watt LEDs seem brighter than a 50 watt halogen.
We typically spend between $15 and $25 per fixture which comes with a halogen lamp bulb. LED replacements are $5 to $10. Well worth tossing the halogens that come with the fixture.
LED vs Incandescent, Halogen?
Not all LED bulbs are equal. The reason I still buy the halogen fixtures; I'm buying a quality LED replacement that I know and have used, not one that comes with a fixture. LED replacements are available for the fixtures we are used to. This way we can put whatever watts LED bulb in a fixture depending on location requirement, controlling light affect. The idea here is fixtures that come with LED to begin with can be more costly and usually need bulb wattage swapped out anyway.
A typical 250 watt halogen install becomes 50 - 65 watts with LED.
How long do bulbs last? Quality and details of installation GREATLY extend average bulb life. This true of halogen, LED, incandescent, for all outdoor installs. Quality of wire connections if the big determining factor. We do not use the quick connectors that come with most fixtures. The quick connectors don't make a perfect connect, and allow moisture into the wire. Poor and decaying connection GREATLY decrease bulb life for any kind of bulb.
50 watt MR16 Low Voltage Cast Aluminum Floodlight, Rust
12V 4W Dimmable MR16 LED Bulb - Warm White 50Watt Equivalent MR16 LED Spotlight - Bi Pin GU5.3 Base - 330 Lumen 60 Degree Beam Angle for Landscape, Accent, Recessed, Track Lighting