Why do we prefer to use low voltage lighting in our projects instead of high (line) voltage lighting? There are a lot of reasons, but let’s cover the big ones here.
Safety! 12 volt lighting is completely safe for man or beast (pet). No one can be electrocuted, pets can’t be shocked, and children can’t be harmed by low voltage lighting that is below 15 volts. There are companies out there that may use transformers that put out as much as 24 volts, but a low voltage lighting company working within the National Electrical Code will NOT use those transformers for landscape lighting because they are not listed for that use. UL 1838 (landscape lighting rated) transformers do not go above 15 volts and are perfectly safe.
With 120 or even 240 volt lighting, there is indeed a safety issue. We often find large high voltage fixtures very high in trees for a moon lighting effect. Although this may look pretty good, strong winds break limbs and those high voltage wires can cause some serious problems. High voltage fixtures require junction boxes (not needed for low voltage lighting) that get water in them from condensation or rain. It’s safe to say that high voltage and water do not play well with each other; whereas low voltage will not even short circuit in water. Here in central Texas, we have also found that, although the code requires all high voltage wires to be at least 18” deep, they rarely are more than 5-6” deep. This makes them easy to hit with your normal garden shovel, or your dog can easily dig them up and chew them causing a potential tragedy. Once again, this is not a problem with low voltage wiring.
Installation expense. Line voltage work must be done by a licensed electrician in all states. The wire must be at least 18” deep, which requires the use of a trenching machine. In some places, a permit may be required and inspections made. All of this adds up to higher expense. In Texas, there is no license needed to install low voltage lighting. Some states do require such licenses, however, but not many. The low voltage wire only needs to be placed 6” deep, which can be easily done by hand using a flat edged spade to avoid tearing up the lawn. No permits (in most parts of the country). These things mean less expense to pass onto the clients. In a future post I will go into the licensing issue because there are several good things about licensing that protect the consumer.
Fixture size. OK, everyone has seen those HUGE fixtures that have those great big high voltage light bulbs in them. The reason the fixture has to be so big is to hold that big light bulb! There is one place where I do think it’s ok to use these products and that is in a commercial setting where there is a lot of ambient lighting around. In these cases you need a LOT of light from some big ol’ fixtures! In a residential setting, or even a commercial setting where the surrounding light levels are low, there is no need for that much lumen output. Low voltage fixtures are much smaller and can be hidden in most cases. They produce plenty of light to handle any residential need.
Design Flexibility. Along with those great big line voltage fixtures, there is little flexibility for lumen output or beam spread in the light bulbs used in them. The primary choices for high voltage lamps are usually bright, brighter and brightest and then wide beam or very wide beam. Although a few new options have been developed, in 90% of the line voltage designs, the standard, less expensive choices are made. With low voltage there is a vast variety of lumen output and beam spreads available. There are also a larger selection of filters and lenses to create effects that are pleasing with the low voltage products. Additionally, many lighting fixtures are available to enhance the décor of the home in a very wide variety of styles.
Maintenance. Maintenance is much easier on a low voltage system than on a high voltage system. First of all, if something goes wrong with a line voltage system, you may have to call in an electrician to find the problem, although a well-trained lighting technician can usually troubleshoot basic problems and solve them. Occasionally, the problem may still require an electrician for the repair. In most states, anyone can work on a low voltage system and any issue with the system can be taken care of right away with no need to schedule another person to come in and make the repairs.
All-in-all the well designed and installed low voltage system has too many advantages to overlook and with some of today’s newest and most efficient LED products, there are considerably more advantages.
| ISSUE | LOW VOLTAGE | HIGH (LINE) VOLTAGE |
| Safety | · No personal harm under 15v· Won’t short circuit in water
· Wiring safe even if uncovered |
· Electrocution hazard· Dangerous near water or rain
· Must trench to 18” to be safe |
| Installation and Maintenance Expense | · No license required in TX; well-trained technician can install, troubleshoot and repair· Wire laid by hand; no lawn damage
· No expensive permit needed in most places |
· May need licensed electrician $· Requires trenching machine to dig 18” deep ditches in yard $
· Permit may be required $ |
| Design Flexibility | · Many options for lumen output and beam spread· Decorative options for added beauty | · Limited options |
| Fixture Size | · Small, easily hidden· Plenty of light output for residential and most commercial applications | · Large, bulky fixtures· May be appropriate for some commercial applications |
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Good article – thanks for posting. I live in a complex where the builder buried some wire for the purposes of potential future landscape lighting. The wire isn’t hooked up to a source yet but unfortunately he buried high voltage wire.
Question: Would it work to connect this wire to a low voltage transformer? Or do we need to use specific low voltage cable?
Hello Damian. If you are using low voltage LED lighting, then feel free to use the existing wire. You shouldn’t have any problems at all. Good luck.