Wiring Components

How To Wire Garden Lights

Wiring can be intimidating to some people however in this project we will be working with low voltage components completely detached from any power supply by an unplugged transformer.


Remember, this entire process as well as the others can be used on any concrete sculpting, or garden light project. Be sure and visit the “ CUSTOMIZE “ page for more ideas!

A transformer converts your homes standard 120V (120 volt) power supply to the much safer and “do it yourself” friendly 12V (12 volt) low voltage power.

A 12V power supply in my area and to my knowledge any other area (check with your local building dept.) does not require a contractor or a permit to install. The wires can simply be hidden in the landscape without the hassle or expense of deep ditches and conduit. Simply hide them under the landscape mulch or edging, under the sod or under a house or porch. The power can be unplugged from the wall outlet for a definite and visual disconnection before any work is done on or around the wires such as adding more lights or digging a hole for a new shrub or tree.

It's really quite simple, just be sure and follow all warnings and directions on the transformer you purchase.


In order to power your lights, you need to hang the transformer in it’s place. So you need to decide which transformer you will use. Which transformer you will use depends on which bulbs you will use.


LED (Light Emitting Diode)  VS. Incandescent (standard bulb)

You’ve probably heard a great deal about LED lights either good or bad. The good is probably right on while the bad is likely stemming from crummy products full of cheap LED’s that put out very little light. Here's some information to help you make your own decision.

A bulb has hidden costs associated with it that need to be considered.

An LED  bulb will cost you many times more dollars on the initial purchase of the bulb, however the savings begin to multiply and add up before you ever even turn them on and the savings continue for the many years life of the bulb. The first place you will begin to see the savings is with the purchase of the transformer.

Transformers are an expensive part of the operation and all are not created equal. They are rated according to how much of a load they can handle. The “load” is how many watts they will run. The more of a load they can handle the more costly they become. To determine the size of a transformer to purchase, just add the total number of light bulbs it will be operating, - say three - and multiply how may watts each bulb will be - say 11 watts each - 3 X 11 = 33 watts. Your load will be 33 watts.



So if you just want a few lights, a bottom dollar low wattage (35-45 watts or so) transformer will be ample whether you burn incandescent bulbs or LED's. If you want more than a few lights though, or if you want to add even one light to your existing landscape lighting transformer that doesn‘t have a whole lot of unused watt capacity left, LED,s quickly become more affordable because of the cost of the transformer.

Light output or brightness of a bulb is measured in “lumens”. A light output of 150 lumens in a standard incandescent bulb will be about 11 watts. An LED bulb with the same 150 lumen light output will be as low as 1 watt.

So if you wanted three landscape lights with a light output of 150 lumens each, and you decided to go with standard incandescent bulbs, You will need a transformer rated at over 33 watts. Three - 11 watt bulbs = (33 watts). The same transformer would operate 33 - 1 watt LED bulbs with the same 150 lumens per bulb light output.

To make matters a bit more complicated, “line loss” can become another factor. As you run wire further and further away from the power source, the load capacity slowly drops. So if you have a 45 watt transformer and intend to run four - 11 watt bulbs (a load of 44 watts) at some distance, the bulbs may be noticeably dimmer or even not work at all. So always purchase a larger capacity transformer than the exact watts you intend to operate unless they are vary near the supply.

You can run more watts at a greater distance by using larger gauge wire.

 Just remember that the cost of the wire goes up with the size of the wire you use.  Wire gauges are rated in a seemingly backwards system, the larger the wire the smaller the number. 12 gauge wire is larger than 16 gauge wire, 10 gauge wire is larger than 12 gauge Etc.

Quick guide for a transformer, wire gauge and run distance.

A 50 watt transformer with:

14 gauge wire will run 50 watts up to 81’

12 gauge wire will run 50 watts up to 129’

10 gauge wire will run 50 watts up to 204’

8 gauge wire will run 50 watts up to 317’

A 100 watt transformer with:

14 gauge wire will run 100 watts up to 40’

12 gauge wire will run 100 watts up to 65’

10 gauge wire will run 100 watts up to 102’

8 gauge wire will run 100 watts up to 158’

A 150 watt transformer with:

14 gauge wire will run 150 watts up to 27’

12 gauge wire will run 150 watts up to 43’

10 gauge wire will run 150 watts up to 68’

8 gauge wire will run 150 watts up to 105’

Also you will need to use wire nuts in the right size. use sizes on the large side to allow for waterproofing of the wire connections.


The next cost to consider is the operating cost. 5-11 watt bulbs compared to 5-1 watt bulbs can be a substantial difference on your power bill over time. Most transformers however come with easy to set timers and a photo eye that senses when it’s dark out. This allows the lights to only come on when it’s dark and automatically shut off after your selected run time.

And finally, the longevity of the bulb . A quality LED can last 100,000 hours as opposed to an incandescent bulb, many are around 10,000 hours. Not only are you going to have to purchase 10 bulbs to last as long as 1 LED, you also have the hassle of driving to the store, standing in line, finding the right bulbs in the isle, not to mention the physical act of actually changing out the bulb 10 times.

In the end, all things considered, LED bulbs are a good choice for many reasons if you can afford the initial purchase.