Outdoor Christmas Lights Keep Tripping GFCI

Quick answer

Turn off all power to the outdoor lights and unplug them. Check for damaged cords or water exposure. Replace any frayed wires and use a GFCI outlet rated for outdoor use.

Confirm the symptom

• Lights are plugged into a GFCI outlet
• GFCI trips when lights are turned on
• Lights work when plugged into a non-GFCI outlet
• Outlet trips even with no other devices connected

Tools and prep

• Non-contact voltage tester
• Multimeter
• Wire stripper
• GFCI outlet tester
• Replacement GFCI outlet
• Weatherproof cover

Disclosure: We may earn a commission from qualifying purchases via affiliate links. Learn more.

Prep & safety

• Turn off power at the circuit breaker before inspecting or replacing any components
• Ensure all lights are unplugged before beginning troubleshooting

Step-by-step troubleshooting

1. Check for damaged cords
   Do: Inspect all light strings and extension cords for frayed wires or exposed conductors
   Observe: Find any damaged sections of cord
   Means: Damaged cord is causing a short or ground fault
   Next: Replace damaged cord or repair with waterproof connectors
2. Test GFCI outlet
   Do: Plug in a known working device and press the test button
   Observe: Outlet trips as expected
   Means: GFCI outlet is functioning properly
   Next: Test lights on a different outlet
3. Test with different outlet
   Do: Plug lights into a non-GFCI outlet to see if they work
   Observe: Lights work without tripping
   Means: Issue is likely with the GFCI outlet or wiring
   Next: Inspect outlet and wiring
4. Inspect outlet and wiring
   Do: Check outlet for water damage or corrosion
   Observe: Find signs of water intrusion or damaged wiring
   Means: Outlet or wiring is faulty
   Next: Replace outlet if damaged
5. Test circuit with multimeter
   Do: Set multimeter to continuity mode and test for shorts
   Observe: Multimeter shows continuity where it shouldn't
   Means: Short circuit in wiring
   Next: Trace and repair the short
6. Replace GFCI outlet
   Do: Turn off power and replace the GFCI outlet with a new outdoor-rated one
   Observe: New outlet works without tripping
   Means: Faulty GFCI outlet was the issue
   Next: Reinstall lights and test

Common causes

Parts you might need

When replacing parts, ensure they match these specifications:

• Outdoor GFCI outlet: match voltage (120V) and amperage (15-20A)
• Weatherproof cover: match outlet size and type
• Replacement light cord: match gauge (18-16 AWG) and waterproof rating
• Wire connectors: match wire gauge and number of wires

Disclosure: We may earn a commission from qualifying purchases via affiliate links. Learn more.

Check the old outlet and cords for printed specifications to ensure compatibility.

When to call a professional

• Frequent tripping persists after replacing outlet and cords
• Unable to locate the source of the short
• Electrical panel shows signs of damage or arcing
• Lights are on a shared circuit with other appliances and tripping continues

FAQ