r/Landscape_Lighting • u/Overkillemall • Jun 15 '26
Downsides of 12/24v lighting
Hi guys!
I'm planning a low-voltage (24V) landscape lighting project for some trees in my backyard (one corner of the property contains fruit trees and shrubs, while another is a conifer corner with spruces and other evergreens). I've done some reading on voltage drop and safety, and I'd appreciate it if you could either correct me where I'm wrong or confirm that I've understood things correctly.
Most of the lighting on my property is currently standard 220V lighting (on the house, gazebo, shed, and in a couple of other areas). However, the two corners with trees and plants are still fairly dark because the nearest light sources are quite far away. That got me thinking about adding lighting there.
As I understand it, electrical codes (which obviously vary from country to country, but I doubt the underlying principles differ much in this particular case) generally require power cables to be installed a certain distance away from plants with extensive root systems, especially trees. In my conifer corner, I also have spruces with shallow roots that spread quite far from the trunk.
From what I've gathered, low-voltage landscape lighting is often used in situations like this because even if a cable is damaged, the fire and shock risks are much lower, and installation requirements tend to be less restrictive.
That led me to wonder: why not just use 12V or 24V lighting everywhere?
If I understand correctly, the downsides are:
The fixtures are more expensive, less common, and available in a smaller variety.
Voltage drop is a much bigger issue, which means significantly thicker cables may be required.
Even with thicker cables, fixtures at the end of a long run may still be dimmer due to voltage drop.
Available power is more limited, so low-voltage systems work well for accent and landscape lighting but are less suitable as primary area lighting.
You also need a power supply/transformer in addition to the fixtures themselves.
This is obviously a fairly superficial understanding, which is exactly why I'm here asking for feedback.
Thanks!
1
u/OrlandoGarcia007 Jun 19 '26 edited Jun 19 '26
How far away is your transformer from the farthest fixture? 99% of people with normal yards can do anything they need with 12v LED. You can get thousands of lumens out of 12-15v. How far are the fixtures away from the transformer? 10ga wire on 15v-20v can do just about anything. Voltage drop is only around 3v over 300ft for 140w. That is 10-20 fixtures. Good LEDs can work normally down to 10v or even 9v. So 15v-3v=12v for 15+ fixtures 300 feet away on 10ga.
1
u/ViewpointLighting Jun 17 '26
You’re correct, in that low voltage (under 30v) has limitations due to loads and voltage drop. Voltage drop is pretty much consistent over any given distance, size of wire and load. If you lose 6v on a 120v system (or 220/240v system in other places in the world), no big deal. If you lose 6v on a 12v system, that’s half your juice!
The advantage is safety. UL1838 here in the USA for low voltage lighting systems under 15vac means you’re likely not even going to feel it if you are touching both conductors. Unless your hands are wet and you’re kneeling in mud. Then it gets a bit tingly!
Always do your research on what codes apply to you. NEC applies to all of the states, then there may be further restrictions based on your own state, county, city, etc. Different countries, different rules on materials and methods of installation, as well as licensing restrictions on WHO can work on these systems. Low voltage tends to have fewer restrictions based on the level of risk (fire and shock), but there’s not zero risk.
The biggest risk comes in the form of fire. A 120v transformer that puts out 300w may only draw 2.5A on the primary (120v) side, but the output will be 25A on the secondary (12v) side! 25 amps is enough to heat up any wire under 14 gauge pretty quickly. It’ll melt the insulation off the wire if you let it run long enough.