Your outdoor lighting looked incredible when it was first installed. But now some fixtures are dark, others are flickering, and you are resetting the same GFCI outlet every other week, wondering what is actually going on.
Outdoor lighting failure is one of the most common service calls we receive from homeowners across Orange County, and the frustrating part is that most of the time, the root cause is something that could have been caught early or prevented altogether.
At All Thingz Electric, we have diagnosed and repaired outdoor lighting systems from Aliso Viejo to Newport Beach to Irvine. This guide breaks down the five most common reasons landscape lighting keeps failing, what each one looks like in the real world, and what it takes to fix it properly, not just patch it.
Reason #1: Low-Voltage Lighting Drop
This is the most misdiagnosed and misunderstood problem in low-voltage outdoor lighting, and it is behind a large percentage of the “my lights are dim” and “some of my lights stopped working” service calls we receive.
Here is how it works. Most residential outdoor lighting systems run on 12 volts of low-voltage current, which is stepped down from your home’s standard 120 volts by a transformer. That 12 volts needs to travel through your yard via buried wire, sometimes 50 feet, sometimes 200 feet or more, to reach each fixture. The longer the wire run, the more electrical resistance the current encounters along the way. That resistance causes a drop in voltage by the time power reaches the fixtures farthest from the transformer.
The result is straightforward. Lights at the beginning of a run look fine. Lights at the end are noticeably dim or completely nonfunctional.
What voltage drop looks like in your yard:
- Fixtures near the transformer are bright, while those farther out are dim or off
- Some zones of your lighting work fine while others seem underpowered
- Bulbs keep burning out faster than they should at the far end of a run
- After adding new fixtures to an existing system, everything got dimmer
The technical threshold that matters:
Low-voltage fixtures need between 10.8 and 12 volts to operate correctly. If voltage at a fixture drops below 10 volts, the light will either be noticeably dim or will not function at all. With halogen bulbs, undervoltage also shortens lamp life significantly. With LEDs, it typically causes the driver to shut off entirely.
What causes voltage drop to get worse over time:
- Underground wire connections that have corroded, increasing resistance at each splice
- New fixtures added to a system that was already running near its voltage limit
- Longer wire runs that were undersized from the start (too thin a gauge for the distance)
- Seasonal changes in utility power delivery, which can affect the transformer’s input
How it’s fixed:
The correct solution depends on the root cause. Options include switching to a multi-tap transformer with 12V, 13V, 14V, and 15V output settings to compensate for longer runs, rerouting wire using a home run or hub wiring method to distribute consistent voltage, increasing the wire gauge for long runs, or adding a second transformer to reduce the load on a single circuit.
If you have never had a proper voltage test performed on your lighting system, this is the place to start. A licensed electrician can measure voltage at multiple points along your wire runs using a multimeter and quickly identify where losses are occurring and what is required to correct them.
Reason #2: An Overloaded or Undersized Transformer
Your low-voltage transformer is the heart of your landscape lighting. It converts 120-volt household current into the 12-volt output your fixtures need. Like any component with a rated capacity, it can be overloaded, which causes repeated failures, shortened lifespan, and a system that keeps shutting off no matter how many times you reset it.
Transformers are rated by maximum wattage. Common ratings include 150 watts, 300 watts, 600 watts, and higher. A critical rule of thumb is that your system’s total fixture wattage should never exceed 80 percent of the transformer’s capacity. A 300-watt transformer should carry no more than 240 watts of total load. Exceeding that threshold causes the transformer’s internal breaker to trip repeatedly, overheats the unit, and accelerates wear on internal components.
Signs your transformer is overloaded or failing:
- Lights work for a few minutes, then everything shuts off
- The transformer feels unusually hot to the touch
- You hear a loud, persistent humming from the transformer housing
- The transformer’s internal breaker keeps tripping
- Lights come on but are dim system-wide, even near the transformer
- You’ve added fixtures to the system over the years without upgrading the transformer
The common story we see in Orange County:
A homeowner who installs a lighting system with a 150-watt transformer and 10 fixtures. Over the following years, they add pathway lights, uplights for new trees, and additional fixtures for updated patio areas. Eventually, they reach 22 fixtures on a transformer that was never designed for that load. The system works for years, but the overload eventually catches up, and the homeowner assumes something is broken when the real issue is capacity.
The fix:
Calculate your total system wattage by checking the wattage of every bulb connected to the transformer and adding them together. If you are running LED fixtures, which we recommend, the wattages are very low and the total load is often well within range.
If the total load exceeds 80 percent of the transformer’s rated capacity, you need to either upgrade to a higher-capacity transformer or split the system across two transformers.
If the transformer is old, magnetic rather than digital, or shows visible damage such as burn marks or corroded terminals, replacement is almost always a better investment than repair.
Reason #3: Underground Wiring Damage and Corroded Connections
This is where landscape lighting problems become genuinely difficult to diagnose because the evidence is buried. Underground wiring and buried connections are exposed to moisture, soil movement, root systems, insects, and anything a shovel or aerator passes through. Over time, these conditions cause two categories of problems: physical damage to the wire itself and corrosion at connection points.
Physical wire damage happens more often than most homeowners realize. Landscaping work, whether it involves planting, installing irrigation, edging, aerating, or even aggressive root growth from established trees, can nick, cut, or compress buried wires. A damaged wire that loses insulation does not fail immediately. It often continues functioning until rain or irrigation saturates the surrounding soil, at which point exposed copper shorts against the wet ground and creates a ground fault.
This is why many homeowners notice their landscape lights fail specifically after it rains or after the sprinklers run, rather than during dry weather. The wire was already compromised, and moisture simply completes the path to ground.
Corroded connections are even more common. Low-voltage systems use pierce point connectors or wire nuts to splice wires at each fixture and along wire runs. When these connections are not fully waterproofed, and many installed with standard wire nuts and electrical tape are not, water gradually infiltrates the splice. Over time, the copper oxidizes, resistance at the connection increases, and conductivity drops. The light at that fixture dims, flickers, or goes dark entirely.
This is also why “some of my lights stopped working” is such a frequent service call. One corroded splice does not take down the entire system, only the fixtures downstream of that connection.
What underground wiring damage looks like:
- Specific sections of fixtures go dark while others work fine
- Lights fail after rain or sprinkler cycles but come back during dry periods
- One zone of your system consistently underperforms
- You’ve had landscaping or irrigation work done in the last year or two
- Lights work fine in summer but start failing during Orange County’s winter rain season
The fix:
This is one area where a licensed electrician with a voltage tester or multimeter is far more efficient than digging up your entire yard. By testing voltage at various points along wire runs, we can identify exactly where conductivity is dropping and pinpoint the damaged section or corroded splice without unnecessary excavation.
Going forward, all underground connections should use gel filled, waterproof wire connectors rated for direct burial, not standard wire nuts covered in tape. Tape breaks down outdoors, water enters the splice, and corrosion begins. Treating every underground connection as if it will eventually be exposed to standing water is the correct approach, because in many Orange County yards, especially those with active irrigation systems, that condition eventually occurs.
Reason #4: Moisture Intrusion Triggering Your GFCI
If your lighting system keeps tripping the GFCI outlet that powers the transformer, especially after rain or irrigation, moisture intrusion is almost certainly the cause. There are several possible entry points.
First, a quick explanation of what is happening. Your outdoor GFCI outlet, the one with the “Test” and “Reset” buttons, is designed to cut power the instant it detects current leaking outside the intended path. That is the safety mechanism working correctly. When moisture enters any part of the system, whether the outlet cover, the transformer housing, an underground wire connection, or a fixture housing, it can create a path for current leakage that triggers the GFCI. The problem is not the GFCI doing its job. The problem is identifying where moisture is entering.
Common moisture intrusion points:
The outlet cover itself is often overlooked. Outdoor outlet covers need to be in-use bubble covers that seal around the transformer plug even when it is plugged in. A standard flat cover, or a bubble cover with a cracked seal, allows water to enter the receptacle during rain. This is one of the most common and most easily fixed causes of GFCI tripping in these systems.
Underground wire connections that were not properly waterproofed are another frequent culprit. When soil around a standard wire nut splice becomes saturated, water can wick into the connection and create a ground fault pathway.
Fixture housings that have cracked or lost their seals over time can allow water to reach the socket and bulb, especially with in-ground well lights and path lights that sit at grade level where water tends to collect.
The transformer housing itself can also develop seal failures around the door or cable entry points, allowing moisture to reach internal components.
Signs moisture is your problem:
- GFCI trips after it rains but resets and holds fine during dry periods
- GFCI trips after sprinkler cycles
- Lights work in summer but start failing when Orange County’s rainy season begins in winter
- You find water inside a fixture housing during inspection
- The GFCI outlet cover is old, flat, or visibly damaged
The fix:
Start at the outlet. Replace any flat cover with a properly rated in-use weatherproof bubble cover and inspect the receptacle for corrosion. If the outlet is old or shows signs of rust or burning, replace it with a weather resistant rated GFCI. Check the transformer door seal and ensure it closes tightly. Then inspect accessible fixtures for cracked housings or failed seals. For underground connections suspected of moisture intrusion, switch to gel filled, direct burial rated waterproof connectors.
If the GFCI continues to trip after these steps, especially if it will not reset even with the transformer unplugged, there is a problem within the wiring circuit itself that requires a licensed electrician to trace and repair.
Reason #5: Wrong Fixtures, Wrong Bulbs, Wrong Environment
Not all landscape lighting failures come from wiring or transformers. Sometimes the system keeps failing because the components themselves are not suited to the environment they are installed in, and Southern California’s outdoor conditions are harder on lighting equipment than most homeowners expect.
The halogen problem:
Many older exterior lighting setup use halogen MR-16 or wedge base bulbs. Halogens are sensitive to voltage fluctuations, burn hot, and have relatively short lifespans, typically 2,000 to 4,000 hours. They also generate enough heat that repeated thermal cycling can degrade fixture sockets and housings over time. If your lights keep burning out every few months, halogens are often the reason.
Switching to LED retrofits or LED native fixtures is the most impactful upgrade most homeowners can make. LEDs draw a fraction of the wattage, run cool, last 25,000 to 50,000 hours, and are far less sensitive to minor voltage variations. One important note: when converting from halogen to LED on an existing system, the total wattage load drops significantly, which can affect how your transformer regulates voltage. A licensed electrician can verify whether your transformer is compatible with the lower LED load before you make the switch.
The IP rating problem:
Not all outdoor fixtures are created equal. Fixtures are rated for water and dust resistance using IP (Ingress Protection) codes. IP44 is typically the minimum for outdoor use, while IP65 or IP67 is recommended for fixtures that sit at grade level, in garden beds with active irrigation, or in areas with heavy rainfall. Fixtures installed without adequate IP ratings will fail prematurely due to moisture and debris infiltration, regardless of how well the rest of the system is installed.
The wrong-wattage problem:
Replacing a burned out bulb with one that does not match the fixture’s rated wattage is a frequent source of repeat failures. Higher wattage bulbs create excessive heat within the fixture housing and shorten socket life. Lower wattage bulbs can cause voltage regulation issues in certain transformer configurations. Always match the replacement bulb’s wattage to the fixture specifications.
The sun-damage problem:
Orange County receives intense UV exposure year round. Plastic fixture housings, lens covers, and wire insulation that are not UV rated will degrade and become brittle over time, leading to cracked housings, compromised seals, and eventually exposed conductors. Investing in bronze, brass, or stainless steel fixtures, along with UV rated wiring, significantly extends the lifespan of an outdoor lighting system in Southern California’s climate.
How to Prevent Landscape Lighting Failures Going Forward
The best outdoor lighting systems are designed for long-term performance from the start and maintained twice a year afterward. Here is what that looks like in practice:
- Use LED fixtures throughout. The lower wattage, longer lifespan, and reduced heat output of LEDs eliminate a large category of landscape lighting problems.
- Don’t exceed 80% of transformer capacity. If you are adding fixtures, calculate the new total load before proceeding.
- Use waterproof, direct-burial-rated connectors on every underground splice. No wire nuts and tape, ever.
- Bury landscape wire at least 6 inches deep. This protects it from edging, aerating, and foot traffic. In areas that are frequently disturbed, run wire through PVC conduit for additional protection.
- Install weatherproof bubble covers on all outdoor outlets. Replace flat covers and cracked covers immediately.
- Schedule a system check twice a year, ideally once before Orange County’s winter rainy season and once after. This is when corroded connections, cracked fixture seals, and transformer issues are easiest to identify before they become larger problems.
- If you’re adding to an existing system, have a licensed electrician assess it first. A voltage test, load calculation, and wiring review before adding new fixtures will save significantly more money than troubleshooting repeat failures afterward.
FAQs About Landscape Lighting Problems
Why do my landscape lights work for a few minutes and then shut off?
This is almost always a sign of a transformer overload or an overheating transformer. The internal breaker trips to protect the unit once it gets hot enough. Let it cool, add up your total fixture wattage, and compare it to your transformer’s rated capacity. If you’re over 80%, the transformer needs to be upgraded or your load needs to be reduced.
Why are only some of my landscape lights not working?
This points to a section-specific problem like a corroded splice, a failed connection at a specific fixture, physical wire damage, or a single bad fixture that’s affecting everything downstream of it. A voltage test along the wire run will pinpoint where the problem is.
Why do my landscape lights trip the GFCI after it rains
Moisture is getting into the system somewhere. Start by checking the outlet cover and the transformer housing seal. If those are intact, the problem is likely a deteriorated underground wire connection or a cracked fixture housing in the area that gets wettest.
Can I add LED fixtures to my existing halogen outdoor lighting system?
Usually yes, but it requires some evaluation first. LED fixtures draw significantly less wattage than halogens, which changes your system’s load profile and can affect how the transformer regulates voltage. Some older transformers don’t perform well at very low loads. Have a licensed electrician assess compatibility before making the switch.
How long should landscape lighting fixtures last?
Quality outdoor fixtures with brass or bronze housings can last 15 to 20 years or more with basic maintenance. Plastic-housed fixtures in Orange County’s UV-intensive environment may start degrading in 5 to 7 years. LED bulbs, in properly sealed fixtures, can last 10 to 15 years before replacement is needed.
My landscape lights flicker. What does that mean?
Flickering usually indicates a loose or corroded connection somewhere in the circuit, a voltage issue (either drop or fluctuation), or a failing transformer. If it’s a single fixture flickering, check the bulb and socket first. If multiple fixtures flicker, suspect a wiring or transformer issue.
Do I need a permit for landscape lighting in Orange County?
Standard low-voltage (12V) landscape lighting typically doesn’t require a permit. However, if you’re installing new 120V line-voltage outdoor lighting, adding outdoor circuits, or upgrading your electrical panel to support a new lighting system, a permit is required. When in doubt, ask your electrician we handle permitting for any work that requires it.
Landscape Lighting Issues in Orange County? We Can Help.
All Thingz Electric is a licensed, family-owned electrical contractor serving residential customers throughout Orange County. We diagnose and repair landscape lighting problems, upgrade transformers and wiring systems, install new outdoor lighting, and handle everything from GFCI troubleshooting to full outdoor electrical system upgrades.
We serve Aliso Viejo, Irvine, Mission Viejo, Laguna Niguel, Lake Forest, Newport Beach, Huntington Beach, Costa Mesa, Tustin, Santa Ana, and all surrounding Orange County communities.
