How to Plan for a Landscape Lighting Installation
To be fully prepared for installing low-voltage landscape lighting systems, you must know how to plan for it. Proper planning will help you understand which landscape lights you need, design your layout, and get the right supplies or accessories. Careful preparation will also help you avoid potential installation problems and figure out which wiring method works best. For the best results, follow our step-by-step guide for an outdoor lighting installation.
1. Choose Your Lights
Before beginning your landscape lighting installation, make sure you understand the different uses of popular landscape lights. Each type of light has its own qualities that make them good for certain applications. Additionally, consider the brightness, color, and color temperature of your outdoor lights. These characteristics can have a significant impact on your landscape design. Decide whether you want a plug-and-play install or if you’re comfortable working with lights that have pigtail wire leads. Pigtail wires will require the use of wire cutters, wire strippers, and silicone-filled twist-on wire connectors or splice connectors to tie into your main landscape line. If you prefer not to use wires in your installation, you might opt for solar-powered lights that do not require a transformer or additional accessories.
After you choose your lights, add up the total wattage they consume. You’ll need this number for choosing other parts of your landscape lighting system.
2. Sketch Out Where Your Lights Will Be
Once you see how you can utilize certain fixtures, create an outdoor lighting design that highlights important parts of your landscape or add practical lighting in popular outdoor spaces. It’s best to make a sketch of the lighting installation area to make sure all areas will receive light coverage. Walk the install location and take measurements. Transfer those measurements to your sketch. Think about light placement and whether the fixture or any accessories will come into contact with mowers or trimmers. This will help you get a clear picture of the best wiring method and how much wire you’ll need. There are several ways you can wire your lights to reduce the amount of wire needed or avoid a power issue known as voltage drop.
3. Calculate Voltage Drop for Wire Gauge or Transformer Voltage Tap
What is voltage drop?
Voltage decreases as it moves through a run of wire and a series of lights. Since each light receives less voltage than the one before, lights can appear dimmer toward the end of a series. A slight loss is acceptable, but correct anything more than a 1.5-volt drop.
To figure out how much voltage drop your system will experience, use this formula: wire length x total light wattage / wire constant x 2. You’ll need to choose a wire gauge for the purpose of this formula. Start with 12 AWG. If the voltage drop is higher than 1.5, try the formula with a larger wire gauge (smaller number). For example, a 10-gauge wire is larger and can handle a higher wattage than a 12-gauge wire. You’ll also need to add up the combined wattage of all your lights. See the table below for wire constants and an example formula where the wire length is 100 feet and the total light wattage is 30.
From our example formula, you can see that voltage drop is 0.8 V, which is acceptable. This means that 12-gauge wire will work for your landscape lighting system.
If you’d rather choose one wire gauge without doing any upfront calculations before purchasing it, consider a multi-tap transformer. This type of transformer has multiple terminals that supply different voltages. To determine which tap you should use on your transformer, use the formula above to figure out voltage drop, and add that number to 12, which is the voltage you want your lights to have. For example, if you have a voltage drop of 3, use your transformer’s 15-volt tap (12+3). You can also use a voltmeter to test what each light receives after you wire them to the transformer.
4. Decide How to Wire Your Low-Voltage Landscape Light:
The daisy-chain method involves end-to-end connection within a series of fixtures where only one end fixture is connected to the transformer. You can save wire by using this method, but it is not ideal for groups of scattered lights. It can also lead to an excessive voltage drop where lights dim toward the end of the series.
In this easy-to-install method, a main line connects to a light in the middle of a series. This way, voltage drop is reduced for uniform brightness across all lights in the series. Not only does the T method help with voltage drop, but it also helps save wire.
In the hub method, the main line connects to a central hub where each light connects separately. This ensures that each fixture receives the same voltage. You can also connect groups of lights to the hub. Each group will start off with the same supplied voltage, but you can still experience voltage drop within each group. It’s important to calculate voltage drop for each group to determine which wire gauge you need or which tap to use on your transformer. The hub method uses more wire than other methods, but it eliminates or reduces an excessive voltage drop and lowers the number of in-ground splices you’d otherwise have.
The loop method powers a series of lights from both ends. The last light in a series runs back to the first fixture or to the transformer. This can be a quick solution for a voltage drop issue with a series of lights, but it can make it difficult to diagnose problems in the future. If you use this method, keep in mind that wire polarity must be maintained from each light to the transformer. While it reduces voltage drop and allows for uniform brightness across your fixtures, it also increases the wiring you need.
In the split method, two or more wire runs are connected directly to the transformer. These runs can have one light or a group of lights connected to them. The split method can reduce voltage drop to each group but could still occur within a series in those groups. Calculate the voltage drop for each group to determine which wire gauge or voltage tap to use.
5. Choose A Power Supply
To determine which power supply is best, consider the total wattage of the lights you’re purchasing and if you anticipate adding lights in the future. When you add up the wattage of all lights, you’ll have a good idea of how powerful your transformer needs to be. The total wattage of your lights should be 20 percent less than the transformer’s rated wattage. Multiply the total light wattage by 1.2 to know which power supply you should buy. For example, if your lights consume 100 watts of power, you’ll need a power supply rated for at least 120 watts (100 x 1.2). If you plan on adding more lights in the future, buy a transformer rated for more wattage than you currently need.
When choosing a power supply, consider if you want one with multiple voltage taps to fix any voltage drop issues easily. Select low-voltage transformers also come with built-in timers or timer receptacles. Dusk-to-dawn photocells can be used to power lights on automatically at dawn and off at dusk. You can also use a voltmeter to check if you need to switch to a higher tap on your transformer.
6. Make Sure You Have The Tools and Materials Needed
Before you get ready to install your lights, make sure you have all the tools and accessories required. Below is a basic list of what you might need. Keep in mind your specific installation could require items that are not on this list.
- Landscape lights
- Silicone-filled wire nuts or splice connectors
- Silicone or burial boxes to protect connections
- Flat-blade shovel or edger
- Wire cutters
- Wire strippers
- Voltage tester
- Tape measure
- Transformer mounting hardware
- Optional 4x4 post for post mounting the transformer
7. Install Your Landscape Lighting System!
Once you have all the necessary supplies, you’re ready to install your lights! To connect the individual wires to the main line, begin by cutting one of the main wires. Then, strip the ends of each wire with your wire strippers and connect those two ends to the two wires coming out of your landscape fixture using a silicon twist-on wire connector. We recommend laying out your entire connected system and testing the lights before burying any wires. After you confirm your system works, bury your lines at least 6 inches deep.
Tips for Your Outdoor Light Installation
- Try a pre-built LED landscape lighting kit. You can save time by trying one of our LED landscape lighting kits. They eliminate the math involved with figuring out voltage drop or choosing wire and a transformer. These kits come with everything you need: multiple low-voltage lighting fixtures, direct burial wire, transformer, and connectors.
- If you plan to use a voltage greater than 120V, you must adhere to the rules and guidelines set by the NEC. It is also recommended to hire a licensed electrician when installing systems using 120V or greater.
- When determining where to install outdoor fixtures, consider using landscape lighting techniques to add dimension to your yard.
If you have any questions, don’t hesitate to call us toll-free at 866-590-3533. Our customer service and technical support teams are available from 8:30 a.m. to 6 p.m. CT Monday-Thursday and 8:30 a.m. to 4 p.m. CT on Friday.