Landscape lighting is one of those upgrades that feels small until you live with it. A well-lit walkway makes coming home calmer, a softly lit patio makes weeknights feel like weekends, and a few strategically aimed spotlights can make your yard look bigger and more polished. So when your landscape lights keep shutting off—randomly, nightly, or right after you turn them on—it’s frustrating in a very specific way: you can’t relax because you’re waiting for the lights to fail again.
The good news is that most “shutting off” problems come from a handful of common causes: power supply issues, overloaded transformers, moisture in connections, voltage drop, timer/photocell confusion, or a fixture that’s failing and taking the system down with it. The trick is troubleshooting in a smart order so you don’t waste time replacing parts that aren’t broken.
This guide walks you through the most likely reasons your landscape lights shut off, how to test each one, and what fixes actually stick. Along the way, you’ll also pick up a few design and maintenance tips so your system stays reliable—whether you’re running a basic pathway setup or a larger multi-zone yard.
First, notice the pattern: when do they shut off?
Before you touch anything, pay attention to the “when.” Do the lights shut off immediately after turning on? After 5–20 minutes? Only on rainy nights? Only when it’s very hot or very cold? The timing tells you where to look first—especially with transformers that have built-in protection modes.
If the lights go out quickly and then come back later (or come back after you reset power), that often points to an overloaded transformer, a short circuit, or overheating. If they fail only sometimes, moisture in a connection or a finicky photocell is a common culprit.
Also note whether all fixtures shut off or only a section. If every light dies at once, start at the transformer, the power source, and the primary cable. If only part of the yard goes dark, you’re likely dealing with a single bad splice, a damaged cable run, or voltage drop on a long line.
Transformer overload: the most common “it works, then it quits” issue
How overload protection behaves
Most low-voltage landscape lighting systems use a transformer (often 12V) that steps down household voltage. Many modern transformers include overload protection. When the connected load (total wattage) exceeds the transformer’s capacity, the unit may shut down to protect itself. Some will stay off until you reset them; others will cycle on and off.
Overload doesn’t always mean you added too many fixtures. It can also happen when bulbs are swapped for higher wattage ones, when fixtures are upgraded without recalculating load, or when a short starts pulling extra current.
In practical terms, overload often looks like this: lights turn on normally, then shut off after a few minutes, especially around dusk when everything kicks on at once.
How to calculate your load (and why you need headroom)
Add up the wattage of every fixture on that transformer. If you have incandescent or halogen bulbs, the wattage is usually printed on the bulb. For integrated LED fixtures, check the fixture label or spec sheet. Then compare the total to the transformer’s rated capacity.
A good rule is to keep your steady load at about 80% of the transformer rating. That headroom helps with heat, prevents nuisance shutoffs, and gives you room to add a fixture later. So if you have a 300W transformer, aim for 240W or less.
If you’re close to the limit, splitting the system into multiple runs (or using a larger or multi-tap transformer) is usually a better fix than “hoping it holds.”
What to do if you’re overloaded
Start simple: temporarily disconnect a few fixtures (or one entire run) and see if the system stays on. If it does, you’ve likely confirmed overload. Then you can decide whether to reduce wattage (switch to LEDs, lower-watt lamps) or upgrade the transformer.
When you’re thinking about upgrades, it’s worth remembering that reliability and aesthetics go together. People often add more fixtures over time because they’re chasing a more finished look—like better curb appeal along the walkway. If you’re planning that kind of improvement, build the electrical capacity to match the vision, especially for stylish pathway lighting for homes where you might use more fixtures at lower brightness to get an even, welcoming glow.
If you’re not comfortable sizing transformers or splitting runs, this is one of those moments where a quick pro evaluation can save you from repeated failures and fried components.
Short circuits and damaged cable: when one problem knocks everything out
Common ways cables get damaged
Low-voltage cable is tougher than it looks, but it’s not invincible. The usual suspects are shovels and edging tools, aerators, pets chewing, rodents, and landscaping changes where someone “just moved a plant” and nicked the wire. Over time, even a staple that was too tight can cut into insulation and create a short.
Damage can also happen at the fixture itself. A stake-mounted light can shift, stressing the cable connection. Or a fixture can fill with water, corrode internally, and start shorting intermittently.
When the transformer senses a short, many units shut down immediately. That’s why a single bad spot can take out the entire system.
How to isolate a short without guesswork
The fastest method is isolation. Disconnect all the lighting runs from the transformer (label them if you have multiple). Then reconnect one run at a time and test. If one run causes the transformer to shut off, you’ve found the “problem branch.”
Next, narrow it down further by separating that run into sections. If you have accessible junction points or splices, disconnect halfway and test again. You’re basically doing a divide-and-conquer search to find the segment with the fault.
If you have a multimeter and are comfortable using it, you can check continuity and resistance on the disconnected cable. A very low resistance reading can indicate a short. But even without tools, systematic isolation usually gets you there.
Repairing cable the right way (so it doesn’t come back)
Once you find the damaged spot, cut out the compromised section and splice in a new piece of cable using waterproof, direct-burial rated connectors. Twist-and-tape repairs almost always fail outdoors, especially after a freeze-thaw cycle.
After repairing, bury the cable a bit deeper or route it away from areas that get edged or aerated. If the damage came from garden work, consider adding a simple map of cable paths for future you (or future landscapers).
If you’re dealing with repeated cable failures, it may be worth upgrading to heavier-gauge wire and rethinking the routing to reduce stress points.
Moisture in connectors: the sneaky cause of intermittent shutoffs
Why water causes “random” behavior
Outdoor connections live in a harsh world: rain, sprinklers, soil moisture, fertilizer, and temperature swings. If a splice isn’t truly waterproof, water can seep in and cause corrosion. Corrosion increases resistance, creates heat, and can eventually lead to flickering, dimming, or full shutoff.
Moisture problems often show up as intermittent failures: the lights work on dry nights but shut off after heavy rain, or they flicker when the ground is saturated. Sometimes the system behaves until the connection warms up, then the resistance increases and the transformer trips.
If your issue seems weather-related, connectors are one of the first places to look.
Where to check first
Start with the most exposed junctions: the first splice coming off the transformer, connections near downspouts, and areas with heavy irrigation. Also check any fixtures installed in low spots where water pools.
Gently tug each wire at the connector. If it slips out, you’ve found a problem. Open any accessible junction boxes and look for green or white crusty buildup—classic corrosion.
Don’t forget the fixture sockets if you’re using replaceable lamps. A corroded socket can cause heat and intermittent contact.
How to redo splices so they stay dry
Use gel-filled or heat-shrink waterproof connectors rated for direct burial. Make sure the wire is clean and the connector is the right size for the gauge. If you’re using heat-shrink, shrink it evenly and fully so it seals.
Whenever possible, keep splices slightly above the soil line or in a proper in-ground rated box. Burying splices directly in wet soil is asking for trouble, even if the connector claims it’s waterproof.
After redoing splices, test the system over a few nights—especially after watering or rain—to confirm the fix is real.
Timer, photocell, and smart controls: when the “brain” is confused
Photocell placement and false readings
Photocells (dusk-to-dawn sensors) are great when they’re placed well. But if the sensor is pointed toward a porch light, streetlight, or even your own landscape lights, it can get confused. The system may turn on, then shut off a few minutes later because the photocell thinks it’s daytime again.
Shadows can also mess with it. A tree branch moving in the wind can cause rapid changes in light hitting the sensor, leading to cycling.
If your lights shut off shortly after dusk—or flicker on and off around twilight—look at the photocell first.
Timer settings that look right but aren’t
Mechanical timers can drift, and digital timers can reset after power interruptions. Some have multiple modes (photocell + timer, timer only, always on) and it’s easy to end up in the wrong one after a reset.
Also, some transformers have separate “on” times for different terminals or zones. If one zone is shutting off while another stays on, check whether you accidentally programmed different schedules.
A quick test is to bypass the timer/photocell temporarily (many transformers have a manual on setting). If the system stays on in manual mode, the issue is likely in the control settings or sensor placement—not the wiring.
Smart transformers and app quirks
Wi‑Fi or Bluetooth-enabled transformers add convenience, but they also add another layer that can fail: firmware updates, time zone settings, daylight saving changes, and connectivity drops. If your schedule seems to “randomly” change, check the app’s time settings and whether it’s syncing correctly.
For troubleshooting, simplify: set a basic schedule, disable fancy scenes, and test stability for a few nights. Once it’s stable, add features back one at a time.
If you’re in an area with frequent power blips, consider a transformer with non-volatile memory that retains schedules without needing a resync.
Overheating transformer: when heat shuts the system down
Why heat happens even with LEDs
Transformers generate heat as they operate, and heat increases when they’re overloaded, installed in direct sun, mounted too close to other heat sources, or enclosed in a way that blocks airflow. Even LED systems can overheat a transformer if the transformer is undersized or poorly ventilated.
Some transformers have thermal protection that shuts them down when internal temperatures get too high. Once they cool, they may turn back on—creating a confusing pattern of on/off behavior.
If your lights shut off more often on hot evenings or after several hours of operation, overheating is a prime suspect.
Quick checks you can do safely
Feel the transformer housing carefully. Warm is normal; too hot to touch is not. Make sure it’s mounted with space around it and not inside a tightly packed enclosure. Check that vents aren’t blocked by leaves, mulch, or debris.
Also confirm the transformer is rated for outdoor use and installed according to the manufacturer’s clearance requirements. A transformer mounted against a dark wall in full sun can run much hotter than the same unit in shade.
If you suspect overheating, try running the system with a reduced load and see if the shutdown stops. That test helps separate “bad transformer” from “transformer pushed too hard.”
Long-term fixes that improve reliability
Relocating the transformer to a shaded, ventilated spot can make a bigger difference than people expect. If relocation isn’t possible, consider a model with better thermal performance or a higher capacity rating.
Splitting the system into multiple runs or adding a second transformer can also reduce heat stress. This is especially helpful for larger yards where you’re powering multiple lighting types (path lights, spots, step lights, wall washes) at the same time.
If the transformer is older or has been repeatedly tripping, replacement may be the most cost-effective option—thermal cycling can wear components over time.
Voltage drop: the “it starts fine, then gets weird” problem on long runs
What voltage drop looks like in real life
Voltage drop happens when electricity travels a long distance through wire and loses voltage along the way. In landscape lighting, it often shows up as dim fixtures at the end of a run, uneven brightness, or lights that flicker or fail when the system is fully loaded.
In some cases, voltage drop can contribute to shutoffs if it causes certain LED drivers to behave unpredictably, or if it leads to higher current draw at the transformer as the system tries to compensate.
If your lights shut off when everything is on, but behave when only part of the system is connected, voltage drop may be part of the story alongside load issues.
Why LEDs can still be sensitive
LED fixtures often include drivers that expect a certain input range. When the voltage dips too low, some drivers will flicker, pulse, or shut down. Other fixtures may stay on but look noticeably dimmer. The mix can make the system feel “haunted” because not all fixtures respond the same way.
It’s also common to see issues when someone mixes fixture brands or mixes older halogen fixtures with newer LED ones on the same run. Different electronics respond differently to voltage changes.
So even if your total wattage is low, long cable runs and mixed loads can still cause annoying behavior.
Fixes: wire gauge, multi-tap, and smarter layout
Using a thicker cable (lower gauge number) reduces voltage drop. So does shortening runs, using a hub method (multiple shorter runs from a central point), or using a multi-tap transformer that lets you send higher voltage down longer runs and “land” closer to 12V at the fixtures.
If you’re redesigning, think in zones: walkway lights on one run, backyard accents on another, and so on. That makes troubleshooting easier and keeps voltage more consistent.
For existing systems, a practical first step is to measure voltage at the transformer and at the farthest fixture while the system is on. If the far end is significantly lower, you’ve got a clear direction for improvements.
Bad fixtures or bulbs: when one failing component causes a cascade
Bulbs that overdraw or fail under heat
With halogen systems, bulbs can fail in ways that create heat or inconsistent contact, especially if the socket is worn or corroded. A bulb that arcs can cause flicker and may contribute to transformer shutdown if it creates a momentary short.
With LED retrofits, the issue can be mismatched bulbs that don’t play nicely with the transformer type (magnetic vs electronic) or with the system’s voltage range. Some LED bulbs are finicky and will flicker or shut down when voltage is slightly off.
If your problem started right after replacing bulbs, that’s a big clue. Try swapping back to a known-good bulb in one fixture and see if the behavior changes.
Fixture water intrusion and internal corrosion
Fixtures that aren’t sealed well—or that were installed in a way that traps water—can fill up over time. Water plus electricity leads to corrosion, and corrosion leads to resistance, heat, and failure. Sometimes the fixture works until it warms up, then shuts off.
Look for fogging inside lenses, rust, or water sloshing when you tilt the fixture. Also check gaskets and cable entry points.
If a fixture is repeatedly filling with water, replacing it with a better-rated model (and improving drainage at the install spot) is usually the real fix.
How to find the “one bad actor” fixture
If the transformer trips and you suspect a fixture, isolate again: disconnect fixtures one by one (or in small groups) from the problem run until the system stays on. The last disconnected fixture is a strong suspect.
Don’t forget to inspect the fixture lead wire. The damage may be on the short pigtail coming out of the fixture rather than the main cable.
Once you identify the culprit, replace or rebuild that fixture and redo its connections with waterproof connectors.
GFCI outlets and breakers: the upstream power issues people miss
How a GFCI can cause “mystery” shutoffs
Many transformers plug into an outdoor GFCI outlet. If moisture gets into the outlet, if the cover doesn’t seal well, or if the GFCI is aging, it can trip intermittently. That looks exactly like “the landscape lights shut off,” because the transformer simply loses power.
Sometimes a GFCI won’t fully trip; it can become sensitive and cut power under load or during humidity spikes. If your transformer display goes blank or resets, check the outlet.
Also verify that the outlet is not shared with other outdoor loads (holiday lights, pond pumps, tools) that might be causing nuisance trips.
What to check at the panel and outlet
Test the GFCI using its test/reset buttons. If it won’t reset reliably, replace it. Check for signs of water intrusion, corrosion, or a loose plug connection. Make sure the in-use cover closes properly with the transformer plugged in.
At the breaker panel, confirm the circuit isn’t overloaded by other devices. If the breaker is warm, frequently trips, or is old, it may need evaluation.
If you’re not comfortable working with line voltage, it’s absolutely okay to stop here and call an electrician or lighting pro—line-side issues are not the place to experiment.
Wiring layout and split zones: designing so troubleshooting is easier next time
Why “one long daisy chain” causes headaches
A common DIY approach is to run one long cable and tap fixtures along the way. It’s simple, but it can create uneven brightness and makes it harder to isolate problems. If something fails halfway, everything downstream may act up.
Long daisy chains also make voltage drop more likely, especially if the wire gauge is light and the fixtures are spaced far apart. The end of the line gets the worst voltage, and those fixtures become the first to flicker or shut down.
When you’re dealing with repeated shutoffs, sometimes the best fix isn’t replacing parts—it’s improving the layout.
Hub method and multiple home runs
The hub method uses a central junction point, then multiple shorter runs branch out to groups of fixtures. This reduces voltage drop and makes troubleshooting easier because each branch is smaller and more predictable.
Multiple “home runs” (separate cables directly from the transformer to each zone) can be even cleaner for large properties. You can dedicate one run to front path lights, one to driveway accents, one to the backyard, and so on.
When a problem happens, you can isolate a zone quickly without turning your whole yard into a test bench.
Labeling and documenting (a tiny habit that pays off)
If you have multiple runs, label them at the transformer. Even painter’s tape and a marker is fine. Keep a simple sketch of where cables run and where splices exist. It sounds extra—until the night something fails and you’re trying to remember what goes where.
Documentation also helps when you hire help later. A pro can move faster when they’re not guessing which cable feeds which area.
If you’re upgrading your yard lighting over time, this habit makes expansions smoother and reduces the chance of accidental cable damage during future landscaping work.
Maintenance habits that prevent shutoffs before they start
Seasonal checkups that take less than an hour
Twice a year (spring and fall), do a quick system walk-through. Look for fixtures that are tilted, buried by mulch, or knocked loose. Check for cracked lenses, exposed wire, and connectors that have popped open.
Clean lenses and remove debris around fixtures so heat can dissipate properly. For well lights and in-ground fixtures, make sure drainage is working and water isn’t pooling.
These small checks reduce heat stress, prevent corrosion, and keep your lighting looking intentional rather than “kind of there.”
Mulch and soil level: the quiet troublemakers
Mulch gets refreshed, soil settles, and suddenly a fixture that was designed to breathe is buried. Buried fixtures run hotter and are more likely to trap moisture. That can lead to shutoffs, flicker, and early fixture failure.
Keep fixtures clear of mulch volcanoes and avoid piling soil around cable connections. If you need to hide hardware, use proper in-ground boxes and rated connectors rather than burying splices loosely.
When you change grading or add garden beds, take five minutes to locate and protect existing cable runs first.
Upgrading components strategically
If your system is older, upgrading the transformer and connectors can dramatically improve reliability even if you keep the same fixtures. Newer transformers often have better diagnostics, and modern connectors are far more water-resistant than the older “pierce” style taps.
LED upgrades can also reduce load and heat, but do them thoughtfully. Mix-and-match bulbs can create compatibility issues. If you’re changing multiple fixtures, try to standardize brands and specs for consistent performance.
And if you’re chasing a certain look—like evenly spaced path lights with soft overlap—plan the electrical side (wire gauge, run lengths, transformer capacity) so the style doesn’t come with constant troubleshooting.
When it’s time to call a pro (and what to ask them)
Signs the problem is beyond quick DIY fixes
If you’ve isolated runs, redone splices, confirmed the load is within limits, and the system still shuts off, you may be dealing with a failing transformer, a hidden cable fault, or a design issue that needs reconfiguration. Another sign is repeated GFCI trips that you can’t explain—those can indicate a more serious electrical leak.
Also, if your property has multiple lighting zones, long runs, or a mix of fixture types, a professional can test voltage under load and spot issues faster than trial-and-error.
Finally, if you’re not comfortable working around line voltage (outlets, breakers), it’s safer to bring in help early.
Choosing the right local expertise
Look for someone who does landscape lighting specifically (not just general electrical) because they’ll understand voltage drop, beam spread, fixture placement, and waterproofing best practices. Ask if they’ll measure voltage at multiple points, check transformer taps, and inspect/replace connectors rather than only swapping fixtures.
If you’re located in South Jersey and want a team that handles layout, troubleshooting, and upgrades, working with Burlington County lighting installers can be a straightforward way to get a system that’s both reliable and good-looking without endless resets and guesswork.
If you’re closer to the shore or dealing with the extra challenges of coastal moisture and salt air, finding pros familiar with those conditions matters. For homeowners looking for help with landscape lights Monmouth County services can be especially useful because weather exposure can amplify connector corrosion and fixture wear.
Questions that lead to a better outcome
When you talk to a pro, ask: “Is my transformer properly sized with headroom?” “Are my cable runs laid out to minimize voltage drop?” “Do I have any splices that should be moved into boxes?” “Are my fixtures rated appropriately for where they’re installed (in-ground, near sprinklers, coastal exposure)?”
Also ask what they’ll do to prevent repeat issues: upgraded connectors, heavier-gauge cable on long runs, multi-tap transformer adjustments, and a quick maintenance plan. The goal isn’t just to get the lights back on tonight—it’s to keep them on all season.
If you like DIY but want a better baseline, you can also ask for a diagnostic visit and a written plan, then decide what you want to tackle yourself.
A simple troubleshooting order you can follow tonight
Step-by-step checklist (fastest path to answers)
1) Check if the transformer has power (is it on, display lit, outlet working, GFCI not tripped). 2) Switch to manual on to bypass timer/photocell. 3) If it still shuts off, disconnect all runs and reconnect one at a time to find the problem branch. 4) If a branch is bad, inspect splices and fixtures for moisture/corrosion and look for cable damage. 5) If all branches cause shutdown, calculate load and consider transformer overload/overheating or transformer failure.
This order avoids the most common trap: replacing fixtures when the real issue is upstream (controls, overload, or a short).
Take notes as you go. Even a quick list like “Run A stable, Run B trips” makes it easier to finish the job without repeating steps.
What to do if you need the lights on for an event
If you have guests coming and just need a temporary win, reduce load by disconnecting non-essential fixtures (often accent spots) and keep only the safety-critical lights (steps, path, entry). That can prevent overload trips and keep the system stable for the evening.
If moisture is the issue, you may be able to temporarily elevate connectors above wet soil and dry them out, but treat that as a short-term patch. Plan to redo splices properly afterward.
And if the transformer is overheating, running fewer fixtures or shortening the on-time can help you limp through the night without full shutdowns.
How to know the fix is truly fixed
Test over multiple nights and conditions. Run the system for at least an hour, then check again later in the evening. If your previous failures happened after rain, test after watering or after the next wet night.
Look for stability: no flicker, no cycling, consistent brightness. If you’ve made multiple changes, try to confirm which change solved it so you don’t undo it later.
Once things are stable, consider a small upgrade pass—better connectors, clearer zoning, and a little extra transformer headroom. Those changes don’t just prevent shutoffs; they make your outdoor lighting feel effortless, which is the whole point.
