Spring is here and it’s time to start thinking about ways to improve the appearance of our yards and the exteriors of our homes. Over the last few weeks I have received numerous calls from customers and potential customers requesting information on landscape accent lighting. I really love landscape lighting because it not only beautifies ones yards by accenting shrubbery, hedges, flower bed, walkways, etc it adds to the security of your home and your person by eliminating the shadows where muggers, rapist and burglars can lurk.
Landscape lighting comes in two style-high voltage and low voltage. Both systems have their strong points and their weak points but for the do-it-yourselfer, the low-voltage route is the best way to go. Working with 24-volts or less is easier and safer for most DIYers, especially if the DIYer is new to working with electricity.
Tools and supplies that you will need
· Shovel
· Tamper
· Silicon sealer
· Caulking gun for use with silicon sealer
· Ratcheting PVC pipe cutter
· PVC pipe-1/2”
· ½” PVC pipe tees
· PVC pipe primer
· PVC pipe cement
· Direct burial wire
· Low-voltage light fixtures
· Low-voltage light fixture supports
· Low-voltage transformer(s) with timer(s)
· Graph paper
Planning is the key to designing and installing landscape accent lighting.
Before you even start thinking about light fixtures, timers, transformers and underground wiring method prepare a detailed drawing of your home and yard on graph paper. A ¼”X1/4” grid where each block represents a specific area, say a 2’X4’ area. The scale you choose depends on the size of your property but this plot drawing should represent a bird’s eye view of your property. Using this plot plan, plan out the positioning of all the light fixtures. Once you know where the lights will go you are in a position to decide what type of fixtures you need and you are in a position to calculate how many of each type you will need. Low-voltage landscape light fixture come in many styles and wattage ratings-spot lights, wall-bracket lights, path accent lights, recessed porch and deck step lights, etc. Low-voltage lights and lighting systems are available at any home center. A good way to determine the number of fixture that you need is to employ these photometric charts and lamp guide pdf. There are four photometric charts and the proper chart to use depends on the last two digits of your lighting devices product code.
For product codes ending in 1 through 31 use http://lib.store.yahoo.net/lib/elights/KichlerPhoto1.pdf
For product codes ending in 38 through 62 use http://lib.store.yahoo.net/lib/elights/KichlerPhoto2.pdf
For product codes 65 and up you should use either of the following charts http://lib.store.yahoo.net/lib/elights/KichlerPhoto3.pdf
http://lib.store.yahoo.net/lib/elights/KichlerPhoto4.pdf
The lamp guide pdf is basically your tool for finding the correct style of bulb to use in a fixture
Fixture and wire layouts.
There are basically four types of installations
The first type is the straight run installation, where all the fixtures are wired sequentially from the transformer.
The second type of installation is the completed loop installation the light fixtures are fed from both ends by the same transformer. This configuration reduces the voltage drop on the circuit. When employing this circuit configuration make sure that you maintain the same polarity when connecting both ends of the loop to the transformer. Most low voltage lighting cable has a raised ridge on one side and this ridged side must be connected to the same transformer screw otherwise you will create a direct short across the transformer’s secondary which will destroy the transformer.
The third type of installation is the split-load installation where there are two or more straight run installations fed by the same transformer. In the split load circuit each straight run circuit is operating at its maximum load which is 250W (Watts) for an AWG (American Wire Gauge) 12 cable.
The fourth type of installation is the “T”-installation which allows for a more even distribution of power to fixtures located at a distance from the transformer. When using a “T” configuration you need to run a heavier gauge cable to the center of the, an AWG 8 or AWG 10 cable is a good choice. Keep in mind that when working with the American Wire Gauge the smaller the number the bigger the wire is. Click here to see illustrations of these four circuit configuration http://www.elights.com/howtodesoutl.html
Selecting the proper transformer(s)
Transformers are rated in VA (Volt-Amperes) which is the maximum load that any transformer can supply safely, exceed this rating and the transformer will be overloaded and burn out. For our purpose here you can think of 1VA as being equal to 1W. Typical low-voltage outdoor lighting transformers have ratings of 60W to over 900W. To calculate the size transformer that you will need for a given installation simply add up the individual wattage ratings of all the lights to be fed by the transformer and multiply by 1.20. Outdoor accent lighting can be expected to be on for more than 4 hours at a time and is therefore considered a continuous duty load and no transformer feeding a continuous duty load should operate at more than 80 percent of it rated capacity. For example if your total calculated load is 400W you need a transformer with a rating of 480W (1.2 X 400W = 480W) or higher. When I design a system I like to allow room for future growth so I would increase this rating by another 25% bringing the minimum rating of the transformer that I would install to a minimum of 600W. When installing any kind of electrical circuits it’s always a good idea to design in capacity for future expansion.
Installing the low-voltage cable
Low-voltage cable is designed for direct burial in shallow trenches but I prefer running it in PVC pipe to protect against accidental damage by lawn and garden equipment like lawnmowers and power edgers. The additional cost of the pipe will be well worth it if you factor in the trouble it would be to dig up a whole run of cable to find out where it was cut. Actually you would probably cut it trying to dig it up so you would end up replacing the whole run of cable, so invest in the PVC pipe. Seal the ends of each section of pipe with silicon to keep water from entering the pipe.
Making the connections
Detailed instructions come with the fixtures and transformers so I won’t go into those detail here.
Conclusion
This is a relative easy project even for a complete beginner. Depending on the size of your layout this project could take anywhere from several hours to several days but the added beauty and security that this project will bring to your home will make the time, money and effort you invest in well worthwhile.
Resources
