#925 Landscape Lighting

Choosing and using the right equipment

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What is the purpose of landscape lighting? What kind of lighting is best for you? How do you choose fixtures, bulbs, wiring and transformers? The following paragraphs will answer these questions and more. Handy installation and maintenance tips are also listed to help with your project.


There are 4 primary reasons for using landscape lighting:

  • • Security
  • • Safety
  • • Direction
  • • Accent

Common Uses:

Landscape lighting is most often used for:

  • •  Path Lighting: Use random and alternate spacing. Don’t outline your walks and driveways like airport landing strips (the runway effect).
  • •  Back Lighting: Use against walls, trellises, or for shadowing trees.
  • •  Highlighting: Use to illuminate trees, plants, or statues.
  • •  Well Lighting: Use in lawns or rock areas. Conceals your light source.
  • •  Flood Lighting: Use to highlight trees, rocks, or buildings.


There are two basic landscape lighting systems for residential use:

The 12 volt lighting system is better known as low-voltage lighting. Because this outdoor system is only 12 volts, home owners can install it themselves. It is safer! Low voltage presents no severe shock risk—and requires smaller trenches and less power. Though you might pay a little more for the system, since it needs special transformers, low-voltage lights and a few more wire leads, you can save on expenses by “doing it yourself”.

The 110-volt lighting system

requires a city or county permit. The finished product is checked by an inspector for code compliance. This system also uses more power. It is cheaper to install and will handle more fixtures without significant voltage drop. (top)

Consider these things when choosing lighting:

  • • Price: How much do you want to spend?
  • • Durability: How long do you want it to last?
  • • Practicality: Which lights are best for you given the budget and durability required?

The next step is to determine how many lights you want and whether or not to start with a set or buy all the components individually. Sets can be less expensive, but have limited expandability. The type of lights desired can also play a role in this question, because not all light styles are available in sets.

Do you buy pre-packaged kits or build the system from individual components? While choosing the correct wiring is relatively simple, the wide range of fixtures and transformers available can cause some anxiety. You must also make a choice between incandescent and halogen bulbs. Let’s explore the possibilities…

Wiring should be multi-strand which is cooler and safer to use. It comes in gauges (sizes) 16, 14, 12 and 10. Remember, the larger the number, the smaller the cable. Use 16 or 14 gauge wire for short runs and light loads only. The 12 gauge wire is best for most residential low-voltage runs. The 10 gauge wire is the more expensive, but is the most effective for extremely long runs.


Fixtures come in a wide variety of styles. There are three basic types:

  • •  Plastic is the cheapest fixture, but biodegrades rather quickly in the sun and must be assembled.
  • •  Metal is the most expensive fixture. It ‘s long-lasting and has a finish that effectively hides spots.
  • •  Half metal/half plastic is a good compromise. It keeps your costs down and lasts considerably longer than plastic, as the metal parts protect most of the plastic parts from the sun.


Transformers vary widely, depending on size. There are three basic types:

  • •  Photocell: Automatically turns lights on at dusk; turns them off at daybreak.
  • •  Timer: Must be manually set. The cheaper transformers have integrated timers that cannot be replaced. Better models have replaceable timers that are not expensive.
  • •  Photocell with Timer: The most versatile type. Allows you to “automatically fix” your system. It must be located outside.

You need to select your transformer with light additions in mind. If you don’t buy enough wattage now, you can’t add to the system later, or you’ll have to buy another transformer. Smart planning saves money. When selecting a transformer, allocate 20% of the stated wattage output for future additions.


Bulbs are available in three basic classes.

    • •  Incandescent. These bulbs come in three types: Bayonet base, Wedge base, and Par-36 (an extra large bulb). They are not as hot as halogen bulbs, cool down quickly, and are cheaper to replace. They also have a shorter life span (600 to 1000 hours) than a halogen bulb.
    • •  Halogen. These bulbs are much hotter and brighter than incandescent bulbs, and are slower to cool. They last longer and are well worth any difference in price. They operate best at 10.8 to 12 volts.

When handling halogen bulbs, don’t touch them with your bare fingers. Oil from the skin causes overheating and rapid blowout. If bulbs are handled accidentally, use a cotton swab dipped in rubbing alcohol to remove oil. Halogens are available in several types:

      • •  JC Type: Bi-Pin (2 prong, no shroud).
      • •  MR-11: Used for fixtures with built-in reflectors.
      • •  MR-16: Bigger bulb with larger shroud; different beam width—narrow for greater illumination at distance—wide for short, broad illumination close-up. Less costly than MR-11 because it is the “industry standard” bulb.
      • •  Par 36: Larger bulb with sealed beam allows handling without worrying about touching bulb with your fingers.
  • •  LED: LED bulbs cost a little more but have an average life of 20,000 to 40,000 hours. They will save much on replacement costs and also have a wider operating range (9 to 15 volts). You can use an integrated LED fixture or retrofit LED bulbs. These retrofits are available in most every style to replace incandescent and halogen bulbs.


Use waterproof connectors instead of the wire clips that come on the fixture. These protect against shorting out fixtures and overloading the transformer.

Always replace burned out bulbs quickly. If not replaced they cause an extra load to be placed on other bulbs, which results in bulb failure throughout the entire run.

Wattage and cable length recommendation:

Wattage of
Control Box
16 Gauge Cable
Maximum Cable
Length (FT)
14 Gauge Cable
Maximum Cable
Length (FT)
12 Gauge Cable
Maximum Cable
Length (FT)
88 watts 100 125 150
120 watts 100 125 150
200 watts 100 125 150
300 watts not recommended not recommended 200
600 watts not recommended not recommended 200(x2)
900 watts not recommended not recommended 200(x3)

Voltage drop should not exceed 1 volt on a 12 v system. If voltage drops below 10.8v at any fixture, a larger cable should be used.

*See Gardening Tip #1021 for addittional information and examples

Multi-volt units must be used with caution. They will solve most voltage problems when used correctly. Consult our lighting experts before using these transformers.

Ask a friendly STAR Irrigation & Lighting Associate at any store for additional help in selecting and installing your landscape lighting system.

©2013, Star Nursery, Inc.