How to Wire Deck Lighting

Updated July 20, 2017

Decks are useful, practical, and even architecturally beautiful. However, what can really set your deck apart from every other one on the block is deck lighting. The most common style -- and easiest to install -- are round in-deck low-voltage lights. The lights are flush-mounted and can be installed in the horizontal deck boards as well as the vertical step risers. This is not only aesthetically pleasing, but also satisfies many cities' building codes requiring stairway illumination.

Plan and sketch out your lighting layout. Determine how many lights you would like to have and where they should go.

Purchase the deck lighting kit. Kits include the lights, bulbs, covers, low-voltage wiring and the transformer. Be sure that the kit contains the correct number of lights based on your design. You can buy individual lights to add one or two lights.

Mark the holes in your deck according to your layout. Make sure you will not be drilling through screws or nails.

Drill a 3-inch hole for each light using the Forstner bit. The Forstner bit will cut a hole with a flat bottom if you do not want to drill all the way through the wood. If this is not a concern, use the hole saw and drill all the way through.

Drill a 3/8-inch hole through the centre of the larger hole. This step only applies if you used a Forstner bit in the previous step. If you drilled a 3-inch hole completely through, go to Step 6.

Feed the wires of the light through the hole, then mount the light base with the supplied screws according to the manufacturer's instructions. Install the bulbs and the trim plates.

Add the total number of lights, then multiply that by the wattage of each light. The total wattage should be less than what the transformer is rated for. Mount the transformer in a sturdy location. If the total wattage of the lights exceeds the maximum wattage of the transformer, mount another transformer.

Wire the transformer to the lights with the supplied low-voltage wire according to the manufacturer's instructions. Wrap electrical tape around all wire-nut connections for a more secure connection.

Plug in the transformer and test the lighting system. Set the timer or photo sensor according to the manufacturer's instructions. Staple all loose wires along joists and beams with the supplied wire staples for a finished look.


If your transformer is equipped with a photo sensor to automatically turn the lights on and off, do not mount the transformer in a very shady or dark place. The sensor is triggered by ambient light and the on/off times will be affected by its mounting location.


Always use the supplied wire staples or staples rated for the gauge of low voltage wire supplied with your kit. Improperly-sized staples may not secure the wires enough or pinch the wires too much, causing an electrical short.

Things You'll Need

  • Drill
  • 3 inch Forstner bit or hole saw
  • 3/8 inch drill bit
  • Deck lighting kit
  • Measuring tape
  • 120 Volt electrical socket
  • Electrical tape
  • Low voltage wire staples
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About the Author

Emrah Oruc is a general contractor, freelance writer and former race-car mechanic who has written professionally since 2000. He has been published in "The Family Handyman" magazine and has experience as a consultant developing and delivering end-user training. Oruc holds a Bachelor of Arts in political science and a minor in economics from the University of Delaware.