Deck Lights Installation: A Guide to Transformer Sizes

Large outdoor kitchen lit up at night
  • 1-8 hours
  • Intermediate
  • 0-200

Installing deck lights can be an optional and attractive way of lighting up your deck. Deck lights should provide adequate lighting in the sitting area while highlighting features of the deck and illuminating steps and walkways. In installing deck lights, low-voltage systems are the best since they are safe and convenient. This requires a transformer, which brings down the voltage for distribution to the lights; the transformer usually has a wire that can be plugged into an exterior outlet near the deck.

Step 1 - Plan the Deck Lighting

Before determining the right transformer for the deck light installation, you first need to come up with a deck lighting plan. On your deck plan, note where the lights will be fixed and where the transformer will be placed in consideration of the adjacent electrical receptacle. Draw up the lines that will route to the wiring circuits. You should also note the stairs, sitting areas, railings, and plantings on your deck plan.

Go to a lighting showroom and present your deck plan to help you buy the specific fixtures you need. As much as possible, there should be a minimal number of wires; connect numerous fixtures to one circuit wire.

You should then compute the total wattage of all the lighting fixtures you will use. This will help you in deciding the size of the transformer you need for your deck lighting. The rule of thumb is that the transformer should be able to provide a minimum of 25% excess capacity of the total wattage for your deck lights.

Step 2 - Select a Transformer

As indicated earlier, a transformer can reduce 120 volts to a more secure 12 volts required for use in low voltage deck lights. In determining the size of the transformer needed for deck lighting, simply add up the power requirements of the lamps to be used and then put an additional 25% for more security.

For example, you may need four step lights of 12 watts, three post lights having 20 watts, and a couple of floodlights of 20 watts. Adding up the total wattage, you get 148 watts; by adding an extra 25 percent excess, you get 37 extra watts for a total of 185 watts.

Good transformers should have numerous options. For one, good transformers must have both high and low switches that act similar to a dimmer. Good transformers too have photocells that can detect light; they will also have lights that automatically turn on once dusk sets in. It should also have timers that work with photocells, and it could be either shut-off or clock-based types. Good transformers too, have thermal protection that prevents overloading.

Since transformers provide a multitude of features, it is important you pick the transformer that will suit the way you plan to tap your deck lighting system. Be sure to get the right transformer for your deck lights by going to a reputable hardware store or home improvement shop. You can also ask the help of a professional to ensure the safety and efficiency of the deck lighting.