Key takeaways
- Most residential landscape lighting is low-voltage: a transformer steps 120V down to 12V, which is what makes buried runs practical and safe.
- The transformer has to be sized for the load with headroom, or you have capped the system before the first expansion.
- Connections are where these systems die. Direct-burial rated connectors in a wet climate, not twist-on caps in a bag.
- Price turns on fixture count, run length, transformer size, and whether an exterior circuit and GFCI protection already exist.
Landscape lighting is one of the few electrical jobs people buy for pleasure rather than necessity, and it is also one of the most commonly redone. Not because the fixtures are bad, though cheap ones are, but because the parts nobody sees were built as though South Texas soil were dry and nothing would ever be added later. A system that is designed properly runs for years with a bulb change now and then. A system that is not starts dropping fixtures the first spring after it goes in.
Low voltage, and why nearly everything residential is
Almost all residential landscape lighting runs at twelve volts. A transformer near the house takes the 120-volt supply down, and everything past it is low-voltage cable run through the yard. That is what makes the whole thing practical: low-voltage cable can be buried at modest depth, the shock risk in a wet yard with a shovel in it is in a completely different category, and adding a fixture later does not mean a conduit run and an inspection.
Line-voltage exterior lighting still has its place, generally for larger fixtures, longer runs where low-voltage drop becomes a problem, and permanent architectural installations. It is a different job: conduit or direct-burial cable at code depth, weatherproof boxes and covers, GFCI protection, and inspection where required. The honest split is that most yards want low-voltage, and the ones that do not usually know why.
Sizing the transformer, and the mistake that caps the system
The transformer has to carry the total wattage of everything connected, and the common error is buying exactly enough. A transformer loaded to its rating has no room for the three fixtures you will want next year, runs hot, and gives you nothing to work with when a bulb gets swapped for something brighter. The convention worth following is sizing so the connected load sits comfortably under the rating, leaving genuine headroom rather than a couple of watts.
Voltage drop is the other half of that arithmetic. Twelve volts does not have much to give away, and a long run of undersized cable arrives at the far fixture dimmer than the near one. The fix is cable sized for the run rather than for the price list, and on larger yards, splitting the system into several runs from the transformer instead of one long daisy chain that fades toward the back fence.
Connections are where these systems actually die
This is the part that separates a system that lasts from one that does not, and it is entirely invisible on the day it is installed. Every splice out in the yard is sitting in soil that goes from bone dry to saturated and back, repeatedly. Standard twist-on wire connectors, even the ones sold with a dab of silicone in a bag, are not built for that and will corrode. What belongs out there are connectors rated for direct burial, properly gel-filled and sealed, on cable that is rated for wet locations.
The failure mode is slow and confusing, which is why so many systems get partially replaced instead of repaired. A corroding connection raises resistance, so the fixtures past it dim before they die. The owner replaces bulbs, then fixtures, and the actual fault is a splice four inches underground between two shrubs. When we get called to a system that is 'losing lights,' the connections are the first place we look, not the last.
- Fixture count and type, which sets the load and therefore the transformer.
- Total run length and layout, which sets cable size and how many runs leave the transformer.
- Whether an exterior circuit with GFCI protection already reaches a sensible transformer location, or one has to be run.
- Trenching conditions, which in a lot of this metro means caliche, and caliche is slower than soil.
- Controls: a photocell, an astronomic timer, or a smart controller that knows when sunset actually is.
For a landscape lighting installation, our flat rate in the book starts at the Landscape lighting task, from $1,179. Fixture count and run length move that number, so a technician walks the yard and confirms the price before anything is trenched, and you approve it before the work starts rather than finding out at the end. Starting price. Your tech confirms the final number on site before any work.
Doing it in stages, deliberately
There is nothing wrong with building a system in phases, and it is often the sensible way to spend the money. The one thing that has to be right on day one is the infrastructure: a transformer with headroom for the finished system, cable sized for the runs you intend to have rather than the ones you are installing this month, and connection points where the next phase will need them. Get that right and phase two is an afternoon. Get it wrong and phase two means pulling up phase one.