How to Size a Transformer for Landscape Lights

Low-voltage landscape lighting is flexible, allowing you to move the lights along the low-voltage cable to achieve your lighting designs. Size your transformer to accommodate all your landscape lights to make sure they all burn bright in your garden or walkway. Low-voltage transformers can vary anywhere from 45 watts to 1,500 watts depending upon the manufacturer. A low-voltage transformer converts 15- to 20-amp, 120-volt electrical current to a safe 12-volt electrical current. By transforming the electrical current down to 12 volts, you can run more lighting using less electricity.

Instructions

1. Open your low-voltage light fixtures to identify the bulb wattage. Low-voltage light bulbs can vary from 1 watt bulbs to 50 watt bulbs.

2. Add up the wattage from all your landscape light fixtures to determine your total wattage needs.

3. Multiply your wattage by 10 percent to allow for any additional light fixtures in the future. For example, if your total wattage equals 332 watts, add an additional 33 watts for a final total of 365 watts.

4. Purchase a low-voltage landscape lighting transformer that provides 400 watts or more of low-voltage electricity for your landscape lighting.

References

• NorthStar Lighting: Design Techniques