Symptoms
- Visible flash or spark when turning the switch on or off
- Popping sound when the switch is used
- Switch cover plate feels warm
Likely causes
- CommonNormal minor arcing in an older toggle switchOlder mechanical switches can produce a tiny, brief spark that's generally harmless.
- CommonA loose wire connection at the switchLoose connections cause more noticeable arcing and heat.
- PossibleControlling a load that's too high for the switch's ratingA switch rated for lights but controlling a higher-draw device can arc more.
- PossibleA failing switch mechanismInternal wear can cause increasingly bad arcing over time.
What to do
- Note how big the spark is and whether it's gotten more frequent or dramatic recently.
- Feel the switch plate for warmth, but stop immediately if it feels hot.
- Turn off the breaker for that switch before doing any inspection.
- Confirm it's dead with a voltage tester, then remove the cover plate to check for loose or discolored wires.
- If wires are loose or scorched, that switch needs replacing rather than reuse.
- Replace an old, worn switch even if wiring looks fine, if sparking has been increasing.
- Have an electrician check the circuit if sparking is large, frequent, or paired with a burning smell.
Tools and parts
- Non-contact voltage tester
- Screwdriver
Replacement light switchSearch: “single pole light switch heavy duty”
When to call a pro
Call an electrician if sparking is large, frequent, paired with warmth or a smell, or if you find scorched wiring inside.
Safety
Use caution
Stop using a switch that sparks noticeably or feels warm, and turn off its breaker until it's been checked or replaced.