Your landscape lights have worked perfectly for months.

Then one night they suddenly shut off.

You check the transformer.

Nothing.

You check the outdoor outlet and discover the GFCI has tripped.

You reset it.

The lights turn on again—only for the GFCI to trip a few minutes later.

Or perhaps everything works perfectly when the weather is dry but shuts down every time it rains.

A GFCI that repeatedly trips is telling you something.

Don't simply keep resetting it.

A Ground-Fault Circuit Interrupter is designed to disconnect power when it detects an imbalance suggesting electrical current may be flowing somewhere it shouldn't.

With landscape lighting, possible causes include:

• Water around the outdoor outlet
• Moisture inside a plug or transformer
• Damaged transformer power cord
• Failed transformer
• Outdoor receptacle problems
• Damaged line-voltage wiring
• Electrical leakage to ground
• Water intrusion into improperly installed equipment
• In some cases, downstream low-voltage faults contributing to transformer problems

The important thing is to troubleshoot the system in the right order.

You don't want to replace twenty landscape fixtures when the actual problem is the outdoor receptacle.

And you don't want to replace the GFCI because it keeps doing exactly what it was designed to do.

This guide will help you determine where the problem is most likely located.

Important: Landscape-lighting transformers connect to household line voltage. This guide focuses on safe observation and low-voltage troubleshooting. Do not open or probe the 120V side of a transformer, outlet, GFCI, breaker panel, or line-voltage wiring unless you are qualified to work on those systems. If the problem points to the 120V side, use a qualified electrician.

What Does a GFCI Do?

GFCI stands for:

Ground-Fault Circuit Interrupter

It monitors the electrical current traveling through a circuit.

Under normal conditions, the current leaving through one conductor should closely match the current returning through the other.

If some current begins leaking through another path—possibly toward ground—the GFCI can disconnect power very quickly.

That additional protection is especially useful in environments where electricity and moisture can come together.

Outdoor electrical equipment faces:

• Rain
• Irrigation
• Humidity
• Condensation
• Wet soil
• Pools
• Sprinklers

which is why a GFCI trip should be treated as a potential safety issue rather than an inconvenience.

Does a GFCI Trip Mean My Landscape Lights Have a Short Circuit?

Not necessarily.

This is one of the biggest misconceptions.

A short circuit and a ground fault are related electrical problems, but they aren't exactly the same thing.

A GFCI primarily responds to current imbalance or leakage toward ground.

A straightforward short circuit on the 12V low-voltage side may instead:

• Trip the transformer's internal protection
• Trigger an automatic circuit breaker
• Cause the transformer output to collapse
• Prevent the lights from operating

without necessarily tripping the household GFCI.

For example, Kings' TSPA60 AC transformer includes automatic circuit-breaker protection for overload and short-circuit conditions.

Therefore:

GFCI trip ≠ automatically a cut 12V landscape wire.

You need to determine which side of the system is actually creating the problem.

Understanding the Two Sides of a Landscape Lighting System

A typical landscape-lighting system contains two very different electrical sections.

Line-Voltage Side

Usually:

120V AC household power

This includes:

• Outdoor receptacle
• GFCI protection
• Transformer power cord
• Transformer line-voltage input

Low-Voltage Side

After the transformer:

12V, 13V, 14V, 15V AC or another specified low voltage

or perhaps:

12V / 24V DC

This includes:

• Landscape cable
• Fixtures
• Bulbs
• Waterproof connections
• Junctions
• Lighting zones

The first troubleshooting goal is determining which side is causing the issue.

Common Reasons Landscape Lighting Trips a GFCI

Here are some of the most common possibilities.

Problem	Likely Location
Wet outdoor receptacle	120V side
Water inside plug connection	120V side
Damaged transformer power cord	120V side
Failed transformer insulation/electronics	Transformer
Water inside transformer enclosure	Transformer
Damaged outdoor extension arrangement	120V side
Failed GFCI receptacle	120V side
Downstream overload/short	Usually transformer protection first
Corroded landscape splice	Low-voltage side
Cut landscape wire	Low-voltage side
Water-filled fixture	Low-voltage side
Incorrect transformer/fixture combination	Low-voltage/system design

The symptom pattern often tells you where to start.

Scenario 1: The GFCI Trips Immediately

If the GFCI trips as soon as the transformer is energized, investigate problems that are present continuously.

Possible causes include:

• Damaged transformer
• Wet transformer
• Damaged power cord
• Wet plug
• Receptacle problem
• Severe electrical leakage
• Line-voltage fault

Do not repeatedly reset the GFCI.

Repeated immediate tripping deserves investigation.

Scenario 2: It Trips Only After Rain

This is a major clue.

If your landscape lights work during dry weather but the GFCI trips during or shortly after rainfall, moisture becomes a primary suspect.

Inspect accessible areas such as:

• Transformer plug
• Receptacle cover
• Transformer enclosure
• Cord entry
• Outdoor connection points
• Nearby irrigation

Do not open energized electrical equipment looking for water.

If moisture appears to be reaching the 120V receptacle or inside the transformer, leave the system off and have the affected equipment inspected.

Scenario 3: It Trips When the Sprinklers Run

Sprinklers can reveal installation weaknesses.

Watch for irrigation hitting:

• Outdoor receptacles
• Transformer vents or openings
• Plug connections
• Damaged electrical enclosures

Also inspect the low-voltage side for fixtures installed directly in constant irrigation paths.

Outdoor-rated does not mean equipment should unnecessarily receive direct high-pressure irrigation every day.

Redirect sprinklers when practical.

Scenario 4: It Trips After Adding New Lights

If the system worked until new fixtures were added, review the modification.

Ask:

• Was transformer capacity exceeded?
• Was wiring disturbed?
• Was the wrong fixture voltage installed?
• Was AC/DC compatibility checked?
• Did a conductor become pinched?
• Was a connection incorrectly made?

An overloaded transformer may activate its own protective device rather than the GFCI, but a system modification can also expose other electrical problems.

Calculate the complete load again.

Scenario 5: It Trips Randomly

Intermittent problems can be frustrating.

Possible causes include:

• Moisture appearing only under certain conditions
• Loose electrical connection
• Failing transformer
• Damaged cord
• Vibration
• Temperature-related failure
• Intermittent receptacle issue

Try to identify a pattern.

Record:

• Weather
• Irrigation
• Time of day
• How long the lights operated before tripping
• Whether another outdoor appliance was running

Patterns make intermittent electrical problems much easier to diagnose.

Step 1: Stop Repeatedly Resetting the GFCI

If the GFCI trips once during an unusual event, resetting according to the manufacturer's instructions may be reasonable.

If it repeatedly trips:

Stop treating the reset button as the repair.

A GFCI is a protective device.

Repeated tripping indicates that the condition triggering protection needs to be investigated.

Step 2: Check Whether Other Equipment Shares the GFCI

Sometimes the landscape transformer isn't the only equipment protected by that GFCI.

The same circuit may also serve:

• Fountain pump
• Outdoor refrigerator
• Holiday lights
• Pool equipment accessories
• Patio appliances
• Other receptacles

Turn off or unplug accessible plug-in equipment and identify whether the landscape transformer is actually the device associated with the trip.

Don't assume the landscaping is responsible simply because the lights went out.

Step 3: Disconnect the Landscape Transformer Plug

With dry hands and only if the receptacle and plug area appear safe and dry, unplug the landscape-lighting transformer.

Then reset the GFCI according to its instructions.

If the GFCI Still Will Not Reset

The problem may involve:

• Receptacle
• GFCI device
• Branch circuit
• Another connected load
• Line-voltage wiring

This is no longer primarily a landscape-fixture troubleshooting issue.

A qualified electrician should inspect the circuit.

If the GFCI Resets Normally

The transformer or its connected lighting system becomes more suspicious.

Continue troubleshooting cautiously.

Step 4: Inspect the Transformer Power Cord

With the transformer unplugged, visually inspect its cord.

Look for:

• Cuts
• Crushed insulation
• Exposed conductor
• Damaged plug
• Burn marks
• Discoloration
• Melted plastic

Do not attempt to repair a damaged 120V transformer cord with ordinary tape.

Replace or professionally repair the equipment according to manufacturer requirements.

Step 5: Inspect the Transformer Location

Landscape-lighting transformers should be installed according to their specific environmental and mounting requirements.

Check whether:

• Irrigation sprays directly onto it
• Water pools around it
• The enclosure has been damaged
• Cord entry is compromised
• The transformer is mounted incorrectly
• Insects or debris have entered accessible areas

Kings currently offers outdoor transformer options with weather-resistant housings, including IP65 stainless-steel models such as the TSRPT600 and STSW300.

Even weather-resistant equipment still needs to be installed according to its instructions.

Step 6: Check the Outdoor Outlet and Cover

Do not disassemble the receptacle.

Instead, visually inspect the accessible exterior.

Look for:

• Broken weather cover
• Water inside the cover
• Corrosion
• Cracks
• Burn marks
• Loose receptacle
• Plug that does not seat correctly

If there is visible damage or water intrusion, leave power off and have the outlet inspected.

Step 7: Determine Whether the Transformer Trips the GFCI by Itself

This can be a useful diagnostic distinction, but only perform manufacturer-approved low-voltage disconnection procedures.

With the transformer unplugged and de-energized, some systems allow the external low-voltage output wires to be safely disconnected from clearly identified low-voltage terminals.

If you are not completely comfortable identifying those terminals, stop and use a professional.

After the low-voltage load is isolated according to the transformer instructions:

• If the transformer still causes the GFCI to trip, the transformer itself becomes a stronger suspect.
• If it operates normally without the landscape load, investigate the downstream low-voltage system.

Do not open internal transformer compartments or access 120V wiring to perform this test.

Why a Low-Voltage Fault Can Still Matter

Although a simple 12V short does not automatically equal a GFCI ground fault, severe downstream problems can stress the transformer.

Examples include:

• Shorted cable
• Water-filled fixture
• Excessive load
• Incorrect wiring

Modern transformers may include built-in protective features designed to respond to overloads or short circuits.

For example, Kings' TSPA DC transformer line lists automatic circuit-breaker protection against overload and short-circuit conditions.

So if the low-voltage side is faulty, you may see:

• Transformer protection trip
• Lights cycling
• Transformer shutting down

rather than—or in addition to—a GFCI issue.

Step 8: Inspect the Landscape Wiring

Once the transformer and line-side equipment appear reasonable, inspect the low-voltage system.

Look for:

• Cut cable
• Exposed copper
• Loose splices
• Corroded connections
• Pinched wire
• Recently disturbed soil
• Damaged fixture leads

Pay particular attention to areas affected by:

• Gardening
• Irrigation repairs
• Fence installation
• Tree planting
• Lawn edging

Wet Landscape Connections Can Cause Problems

Outdoor splice quality matters.

Kings' 12/2 and 14/2 direct-burial wire product information specifically warns that joints exposed to wet conditions can corrode copper conductors and contribute to early failure.

Good outdoor connections should be made using connection products intended for the installation environment.

Don't rely on:

• Indoor wire nuts
• Twisted copper and tape
• Exposed screw connections
• Unsealed splices

for permanent underground landscape wiring.

Step 9: Inspect Fixtures for Water Intrusion

Landscape fixtures live in difficult environments.

Possible water-entry locations include:

• Lens gasket
• Fixture cap
• Cable entry
• Socket
• Damaged housing

Look for:

• Water behind the lens
• Condensation
• Corroded bulb pins
• Rust or mineral deposits
• Green copper corrosion

If one fixture is obviously filled with water, disconnect and service it according to the manufacturer's instructions before operating the system again.

Can Water in a 12V Fixture Trip the GFCI?

Not always directly.

Remember:

The landscape fixture is on the low-voltage side of an isolated transformer in many systems.

A wet low-voltage fixture may instead cause:

• Short circuit
• Transformer overload protection
• Corrosion
• Flickering
• Failed fixture

Whether that condition contributes to an upstream GFCI trip depends on the transformer and exact fault path.

Therefore, don't assume:

Wet fixture = definite GFCI cause

but don't ignore wet fixtures either.

They indicate a problem that should be corrected.

Step 10: Calculate Transformer Load

An overloaded lighting system can cause transformer problems.

Calculate:

Fixture count × watts per fixture

Example

12 spotlights × 5W = 60W

10 path lights × 3W = 30W

6 step lights × 3W = 18W

Total Load

108W

Compare this with the transformer's permitted loading requirements.

Kings' TSPA60, for example, is rated at 60W but recommends operating within 80% of capacity for optimal performance.

Other models have different loading specifications.

Always follow the specific transformer instructions.

A 300W Transformer Does Not Mean You Should Use 300W

Transformer ratings indicate capacity.

Some products specify that they should not be operated continuously at their absolute maximum rating.

The TSRPT600, for example, uses two 300W outputs and Kings specifies that each output should not be loaded beyond 85% of its capacity.

When sizing a transformer, leave the margin recommended by its manufacturer.

Check AC vs. DC Compatibility

A wiring system can also malfunction when incompatible equipment is mixed.

Check whether your transformer supplies:

AC

or

DC

Then verify every connected fixture.

Kings' STSW300, for example, outputs 12V/15V AC and is specified for compatible AC LED and halogen products—not DC bulbs.

Kings also offers separate DC transformer products for compatible 12V/24V DC fixtures.

Smart, waterproof, or low-voltage does not mean universally compatible.

Does a Damaged Landscape Wire Trip the GFCI?

A cut low-voltage cable can certainly create a lighting fault.

But once again, it will not necessarily trip the household GFCI.

A damaged 12V cable might cause:

• Short circuit
• Transformer protection activation
• Dead lighting branch
• Flickering
• Reduced voltage

If you suspect buried wire damage, identify the:

last working fixture

and:

first dead fixture

Then use voltage testing to narrow the fault location.

How to Check for a Low-Voltage Short

On the low-voltage side, warning signs include:

• Transformer protection repeatedly trips
• Lights briefly flash and shut off
• Transformer output disappears under load
• Cable becomes unusually warm
• Problem begins immediately after landscaping work

Do not keep operating a system with signs of a short.

Turn it off and inspect the affected branch.

What If the Transformer Works With No Lights Connected?

If a transformer operates normally with its low-voltage lighting load safely disconnected according to manufacturer instructions, but shuts down or creates problems once a particular branch is connected, the fault may be on that branch.

Possible causes include:

• Shorted cable
• Failed fixture
• Damaged connector
• Water intrusion
• Excessive branch load

Reconnect branches individually only when the system design and manufacturer instructions allow safe low-voltage isolation.

This can help identify which zone contains the problem.

Divide the Landscape Into Zones

Large systems are easier to troubleshoot when wired in multiple branches.

For example:

Branch 1 — Front walkway

Branch 2 — Trees

Branch 3 — Backyard

Branch 4 — Patio

If connecting Branch 3 causes the transformer to fault while all other branches operate normally, you've narrowed the problem to the backyard.

That's much easier than inspecting every fixture across the property.

Why Hub Wiring Can Help Troubleshooting

Hub and multi-branch designs make sections easier to isolate.

Instead of one extremely long daisy chain, a centralized hub can distribute power to several branches.

If one branch develops a fault, the others can be tested independently.

This is one reason system organization matters beyond initial installation.

What If the GFCI Trips Only When the Lights Turn On at Sunset?

A photocell-controlled system may operate normally all day because the transformer isn't energizing the lighting load.

Then darkness arrives.

The photocell activates the transformer.

The GFCI trips.

Possible causes include:

• Transformer fault that appears under load
• Downstream electrical problem
• Overloaded transformer
• Moisture-related failure

Temporarily using the transformer manufacturer's manual/test mode during troubleshooting can help reproduce the condition during daylight without waiting for sunset.

What If It Trips Several Hours After Turning On?

Time-delayed failures may suggest:

• Transformer overheating
• Moisture or condensation
• Intermittent internal fault
• Load problem
• Temperature-sensitive component

Record how long the system operates before the trip.

If the pattern is consistent, that information can be useful to a technician.

Could the GFCI Itself Be Bad?

Yes.

GFCI devices do not last forever.

A worn or damaged device can become unreliable.

But don't assume the GFCI is bad simply because it trips.

Replacing a protective device without investigating the underlying cause could hide a real electrical problem.

If the GFCI:

• Will not reset with loads unplugged
• Feels loose
• Is visibly damaged
• Shows signs of heat
• Trips unpredictably with multiple different appliances

have the circuit inspected by an electrician.

Could a Bad Outdoor Receptacle Be the Problem?

Yes.

Outdoor receptacles face:

• Moisture
• Temperature changes
• Dirt
• Corrosion
• UV exposure

Problems can develop around:

• Contacts
• Wiring
• Cover
• Weather seal

Do not open or repair the receptacle yourself unless qualified.

Why Transformer Placement Matters

Even a weather-resistant transformer should be positioned intelligently.

Avoid locations where possible where:

• Sprinklers continuously spray it
• Water collects
• Snow or debris accumulates
• Ventilation is blocked
• The cord sits in water

Follow the mounting and clearance instructions for the specific transformer.

Kings' TS200, for example, is an outdoor 200W 12V AC transformer with a digital timer and weather-resistant design.

Browse Kings Low-Voltage Transformers

Why Waterproof Landscape Splices Matter

Kings' direct-burial wire guidance makes a useful point:

Even when the wire itself is suitable for direct burial, the splice still needs proper protection.

That's because the weak point in many landscape-lighting systems isn't the cable.

It's the connection.

Moisture can enter a poorly protected splice and gradually corrode the copper.

That can lead to:

• High resistance
• Flickering
• Voltage drop
• Intermittent operation
• Complete failure

Use outdoor-rated connectors appropriate for the cable and installation environment.

Shop Kings Direct-Burial Landscape Wire

Troubleshooting After Heavy Rain

If the GFCI only trips after heavy rain:

1. Leave the system off if anything appears wet or damaged.

2. Inspect the accessible transformer, plug, and receptacle area.

3. Check for water accumulation.

4. Look for fixtures filled with water.

5. Inspect accessible low-voltage junctions.

6. Allow wet equipment to be evaluated rather than repeatedly resetting protection.

7. Have the 120V receptacle/circuit inspected if moisture may have entered it.

Do not use heat guns, open flames, or improvised drying methods on electrical equipment.

Troubleshooting After Irrigation Changes

A new sprinkler layout can cause a previously reliable installation to begin having moisture problems.

Check whether a sprinkler now sprays directly onto:

• Transformer
• Outdoor receptacle
• Plug
• Junction location
• Fixture openings

Sometimes the electrical equipment didn't change.

The water pattern did.

Troubleshooting After Landscaping Work

If the GFCI or transformer began tripping immediately after digging:

Inspect the affected low-voltage branch for:

• Cut cable
• Crushed cable
• Pinched fixture leads
• Damaged connectors

A shovel can partially damage a conductor without completely cutting it.

That can produce intermittent symptoms.

GFCI Trip vs. Transformer Circuit Breaker Trip

These are two different protective events.

GFCI Trip

Usually points toward:

current leakage / imbalance on the line-voltage circuit

Transformer Breaker/Protection Trip

More commonly points toward:

• Low-voltage short
• Overload
• Excessive load
• Downstream wiring fault

Knowing which device actually trips is critical.

Ask:

Did the outdoor GFCI outlet trip?

or:

Did the transformer's own breaker/protection trip?

Those are not the same diagnosis.

Why Your Landscape Lights May Shut Off Without the GFCI Tripping

If the GFCI remains powered but the landscape lights shut down, investigate:

• Transformer internal breaker
• Timer
• Photocell
• Smart schedule
• Transformer overload
• Shorted low-voltage branch
• Failed transformer

The GFCI doesn't have to trip for the lights to go out.

Common GFCI Troubleshooting Mistakes

Mistake #1: Resetting It Over and Over

Repeated trips indicate a problem.

Mistake #2: Blaming the Landscape Bulbs Immediately

A GFCI trip often points farther upstream.

Mistake #3: Assuming Every Low-Voltage Short Trips the GFCI

Transformer protection may respond instead.

Mistake #4: Ignoring Rain Patterns

Weather-related timing is valuable diagnostic information.

Mistake #5: Opening the Transformer

Don't access internal 120V wiring unless qualified.

Mistake #6: Replacing the GFCI Without Diagnosis

The GFCI may be protecting you from a legitimate fault.

Mistake #7: Ignoring Transformer Load

Check total fixture wattage.

Mistake #8: Using Indoor Wiring Connections Outdoors

Moisture protection matters.

Mistake #9: Ignoring AC/DC Compatibility

Match transformer and fixtures correctly.

Mistake #10: Continuing to Operate Wet Electrical Equipment

Turn it off and correct the moisture problem.

Quick Diagnostic Flow

Use this troubleshooting order:

GFCI keeps tripping

↓

Unplug landscape transformer

↓

Can GFCI reset and remain on?

NO → Receptacle/circuit/other line-voltage problem → electrician

YES → Transformer/system becomes suspect

↓

Inspect transformer cord, plug, enclosure and moisture exposure

↓

If manufacturer-approved, isolate low-voltage output with transformer unplugged

↓

Transformer alone trips GFCI?

YES → Transformer fault becomes more likely

NO → Investigate low-voltage branches

↓

Check for shorted wire, wet fixtures, bad connectors or overload

This workflow helps separate the 120V issue from the landscape-lighting issue.

When Should You Replace the Transformer?

A transformer becomes a stronger replacement candidate when:

• It trips the GFCI even with the approved low-voltage load isolated
• Its cord is damaged
• Its enclosure is compromised
• Water has entered internal areas
• Output is unstable
• Internal protection repeatedly trips under a verified proper load
• Manufacturer troubleshooting indicates failure

Do not replace the transformer simply because one landscape fixture stopped working.

Test systematically first.

Choosing a Replacement Landscape Transformer

If replacement is necessary, check:

Output Type

AC or DC?

Voltage

12V?

12V/15V?

12–15V multi-tap?

24V DC?

Wattage

What is the total fixture load?

Controls

Do you need:

• Photocell
• Timer
• Astronomical control
• Smart Wi-Fi

Environment

Is the transformer rated for its installation location?

Kings offers AC, DC, smart, timer-equipped, photocell, and multi-tap transformer options.

Shop Low-Voltage Landscape Lighting Transformers

Example: Small 12V AC System

Suppose you have:

8 path lights × 3W = 24W

4 spotlights × 5W = 20W

Total:

44W

A compatible 60W transformer may appear sufficient based on wattage alone.

But you must also verify:

• Manufacturer loading limits
• Voltage
• AC compatibility
• Wire distances

Kings' TSPA60 provides 60W AC 12V output, photocell control, countdown-timer options, and built-in circuit protection.

Example: Larger System

Suppose you have:

20 spotlights × 5W = 100W

20 path lights × 3W = 60W

10 step lights × 3W = 30W

Total:

190W

A 200W transformer may be too close to its maximum depending on the manufacturer's recommended loading limit.

A larger transformer with appropriate headroom may be the better choice.

Don't size solely by choosing the smallest transformer whose printed wattage is slightly larger than your fixture total.

Can Smart Wi-Fi Transformers Trip GFCIs?

They can experience the same underlying electrical problems as non-smart transformers.

Wi-Fi control doesn't eliminate issues such as:

• Moisture
• Damaged cords
• Internal faults
• Incorrect load

Kings' STSW300, for example, combines smart control with 12V/15V AC output, photocell, digital timer, stainless-steel construction, and an IP65 rating.

The smart features provide control.

They do not replace proper electrical installation.

Preventing Future GFCI Trips

Once the system is repaired, improve long-term reliability.

Keep the Transformer Properly Positioned

Follow installation requirements and reduce unnecessary water exposure.

Protect the Receptacle

Use proper outdoor electrical equipment and weather protection.

Waterproof Low-Voltage Splices

Moisture and exposed copper are a bad combination.

Use Direct-Burial Cable

Select outdoor landscape wire appropriate for the installation.

Kings' current 12/2 cable uses 100% copper conductors, UV-resistant insulation, and is designed for direct-burial low-voltage landscape-lighting applications.

Keep Sprinklers Away From Electrical Equipment

Redirect irrigation where practical.

Check Transformer Capacity Before Adding Fixtures

Don't continually add lighting without recalculating the load.

Inspect Fixtures Periodically

Look for:

• Broken lenses
• Water
• Loose caps
• Damaged cables

When Should You Call an Electrician?

Stop troubleshooting and use a qualified electrician if:

• GFCI will not reset with the transformer disconnected
• Outdoor receptacle appears damaged
• Water entered the 120V receptacle
• Breaker trips
• Transformer plug or cord is burned
• You smell burning
• Equipment is overheating
• The issue involves household wiring
• You would need to open line-voltage equipment to continue testing

Low-voltage landscape wiring is one thing.

The 120V supply feeding the transformer is another.

Respect the boundary between them.

When Should You Call a Landscape Lighting Professional?

A landscape-lighting technician may be better suited when:

• Transformer operates but downstream branches fail
• Fixtures flicker
• Multiple low-voltage connections are corroded
• Buried cable is damaged
• Voltage drop is excessive
• Transformer sizing needs to be recalculated
• Wiring layout needs redesign

For complex problems, an electrician and landscape-lighting specialist may work on different parts of the system.

Final Verdict: Why Is Your Landscape Lighting Tripping the GFCI?

A repeatedly tripping GFCI should not be ignored.

The most likely categories to investigate are:

1. Moisture around the 120V outlet, plug, cord, or transformer

2. Damaged transformer or line-voltage equipment

3. Outdoor receptacle or GFCI problem

4. Transformer failure

5. Downstream low-voltage faults or overload stressing the lighting system

Start with the safest and easiest distinction:

Does the GFCI remain reset when the landscape transformer is unplugged?

If it does not, the problem likely isn't something you should solve by replacing path lights.

If it does, the transformer and landscape-lighting system deserve further investigation.

Then move systematically:

Transformer → Branches → Wire → Connections → Fixtures

Don't guess.

Don't keep resetting.

And don't bypass the GFCI.

The protective device is telling you something.

Find the cause.

Shop Landscape-Lighting Repair & Replacement Components

If troubleshooting reveals damaged or incompatible landscape-lighting equipment, Kings Outdoor Lighting carries the major components used throughout a low-voltage installation.

Low-Voltage Landscape Lighting Transformers
AC, DC, multi-tap, photocell, timer, and Smart Wi-Fi options.
Shop landscape-lighting transformers

12/2 Direct-Burial Copper Landscape Wire
100% copper, UV-resistant low-voltage outdoor cable.
Shop 12/2 landscape wire

14/2 Direct-Burial Copper Landscape Wire
A smaller-gauge option for appropriately designed low-voltage runs.
Shop 14/2 landscape wire

Landscape Lighting Fixtures
Spotlights, path lights, well lights, step lights, hardscape fixtures and more.
Browse low-voltage landscape lights

A reliable outdoor-lighting system depends on every part working together:

Power source → GFCI protection → Transformer → Wire → Connections → Fixtures

One weak component can affect the entire system.

Frequently Asked Questions

Why does my landscape lighting keep tripping the GFCI?

Possible causes include moisture around the receptacle or transformer, damaged transformer wiring, electrical leakage, a failing transformer, outdoor receptacle problems, or other faults in the lighting system.

Why does my landscape-lighting GFCI trip when it rains?

Rain-related trips strongly suggest moisture is reaching electrical equipment or exposing an existing insulation or equipment fault. Inspect accessible outlets, plugs, cords, and transformer locations and have line-voltage equipment professionally inspected when necessary.

Why does my GFCI trip when the sprinklers come on?

A sprinkler may be spraying the transformer, receptacle, plug connection, or damaged electrical enclosure. Check irrigation patterns and eliminate unnecessary direct water exposure.

Does a low-voltage short trip a GFCI?

Not necessarily. A low-voltage short commonly activates transformer overload or short-circuit protection. A GFCI primarily responds to current imbalance or leakage on its protected line-voltage circuit.

Can a bad landscape transformer trip a GFCI?

Yes. A transformer with an internal electrical fault, insulation failure, damaged power cord, or moisture intrusion can potentially cause GFCI protection to operate.

Can a wet transformer trip the GFCI?

Potentially, yes. If moisture creates an unintended leakage path on the line-voltage side, GFCI protection may trip.

Can wet landscape lights trip the GFCI?

A wet low-voltage fixture may cause a short, corrosion, or transformer protection to operate. Whether it directly causes an upstream GFCI trip depends on the transformer and exact electrical fault.

Why does the transformer keep shutting off but the GFCI does not trip?

The transformer's internal overload or short-circuit protection may be operating. Check system wattage, wiring, and downstream shorts.

How can I tell if the GFCI or transformer is bad?

With the transformer safely unplugged, see whether the GFCI can reset and remain on. If it still cannot, the line-voltage circuit or GFCI should be professionally inspected. If it remains on until the transformer is connected, the transformer/system becomes more suspicious.

Should I keep resetting a GFCI that trips?

No. Repeated tripping indicates a condition that needs investigation.

Can I bypass the GFCI for my landscape transformer?

Do not bypass electrical safety protection to keep the lights operating. Correct the cause of the trip.

Can too many landscape lights trip the GFCI?

An excessive low-voltage load more commonly activates transformer overload protection. However, an overloaded or failing system should still be corrected immediately.

How do I know if my transformer is overloaded?

Add the wattage of all connected fixtures and compare the total with the transformer manufacturer's permitted loading requirements.

Does a 300W transformer always support 300W of landscape lights?

Not necessarily. Manufacturers may specify a maximum recommended percentage of rated capacity. Follow the requirements for your specific transformer.

Can a damaged buried wire cause landscape lights to shut off?

Yes. A cut or shorted low-voltage cable can cause dead fixtures, transformer protection, or intermittent lighting.

Can a corroded landscape-wire connection cause electrical problems?

Yes. Corrosion increases resistance and can lead to flickering, voltage drop, intermittent operation, or complete failure.

Should landscape-lighting wire connections be waterproof?

Outdoor and underground connections should use connection methods designed for wet or damp landscape environments.

Can I use indoor wire nuts for underground landscape lighting?

Use connectors specifically designed for the installation environment. Ordinary indoor connection methods are generally not appropriate for permanent wet underground landscape splices.

Why does my GFCI trip as soon as the landscape lights turn on?

Possible causes include a transformer fault that appears under load, moisture, electrical leakage, or another problem activated when the transformer energizes.

Why does my GFCI trip after the lights have been on for an hour?

Delayed trips may point toward heating, moisture, intermittent transformer failure, or another condition that develops after the equipment operates for some time.

Can a photocell cause a GFCI to trip?

A normal photocell shouldn't create a ground fault. However, a damaged transformer or control assembly could have electrical problems requiring inspection.

Can a smart landscape transformer trip a GFCI?

Yes. Smart connectivity does not change the basic electrical safety requirements of the transformer.

Does AC vs. DC matter when troubleshooting a GFCI?

It matters for transformer and fixture compatibility. However, the GFCI is normally protecting the line-voltage supply feeding the transformer.

What should I do if the GFCI trips during rain?

Leave the system off if wet or damaged electrical equipment is suspected. Inspect accessible areas without opening energized equipment and have the line-voltage portion professionally evaluated where necessary.

When should I replace the landscape transformer?

Replacement may be appropriate when the transformer is confirmed to have an internal fault, damaged cord, compromised enclosure, unstable output, or repeated protection trips under a verified proper load.

When should I call an electrician?

Call an electrician when the GFCI will not reset with the transformer disconnected, when the outdoor receptacle or line-voltage wiring is damaged or wet, when breakers trip, or whenever troubleshooting requires access to the 120V system.