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Low Voltage Layout Guide
Laying out an installation plan for a low voltage landscape lighting system is fairly straightforward but does require knowing a few things. This article covers the main steps and gives guidance and tips to ensure a successful installation.
The Basic Layout
There are four main components to a landscape lighting system.
1. Start a Sketch. Most lighting designers begin their layout by creating a rough sketch of the property - or several sketches, one for each area. Try to be as accurate as possible with your sketch because you will be using it to help estimate distances for wire runs. You can use a blank piece of paper or graph paper. Attach this to a clipboard so you can walk the property and sketch as you go along.
2. Set Transformer Location. The best placement for the transformer is usually next to the house in a hidden location (behind a garden bed, near air conditioning equipment, etc.) It should be as close as possible to the fixture locations. Sometimes it makes sense to use more than one transformer - especially when fixtures are situated throughout a large property. If multiple transformers are used then create a separate plan for each one. Mark transformer locations on your sketch.
3. Set Fixture Locations. Before you install any fixtures in the property, mark their approximate positions in the landscape using small flags or pencils. Indicate the positions on your sketch and mark what fixture types will go at each location. As you walk the property, make rough measurements to indicate the distances between fixtures and the transformer, and between the fixtures themselves.
4. Determine Wire Runs. Now, the task is to plan how to provide power to the fixtures. There are many wiring methods available. You don't want to run a single wire from each fixture to the transformer - 20 fixtures, 20 wires all ending at the transformer - that would waste a lot of wire. Instead, we minimize the total amount of wire by using one of the following wiring methods.
Tips on Selecting the best method:
Layout TIPS for Optimal Installation and Results:
Lower loads per run means lower voltage drop. This is not much of a concern for LED systems since voltage drop for most systems is minimal. But if your system is large (more than 15 fixtures or about 100W) break your layout up into multiple cable runs of ~ 100-150 watts per run. If you have more than 150 watts in an area -- break it up into 2 runs. For LEDs, lower wattages mean you can group more fixtures onto single runs, but keep in mind that it still makes sense to use one home run wire for each zone; this is more energy efficient and makes for easier troubleshooting.
Break your layout into Distance Zones. For example, put fixtures 15-30 ft away from the transformer on one run; fixtures 25-40 ft on another run; fixtures 30-50 ft on another run; and so on. The goal is to have all the fixtures on a run be roughly the same distance from the transformer so they have similar amounts of voltage drop. That way when you adjust for voltage drop by increasing the voltage for that one run, the lights are not over-volted or under-volted.