Light Not Working: Causes, Checks & Fixes

Stop if there is heat, burning, arcing, exposed parts or water near the light

Do not open fittings, switches or junctions while energised. Isolate the lighting circuit and call a registered electrician where danger signs, water ingress or fixed wiring faults are present.

MOST LIKELY CAUSES

Start with these

Failed lamp The bulb or LED module may simply have reached end of life.

Tripped breaker or RCD The lighting circuit may have been disconnected.

Faulty switch The switch mechanism or connection may have failed.

Fitting or driver fault LED drivers, transformers and lampholders can fail.

◫ Symptom variations Match the exact behaviour before testing. ⌄

One light is dead
The lamp flashes briefly then goes out
A replacement lamp also fails
The switch feels loose
The light stopped after building work

✓ Quick checks Safe checks before opening any fitting or switch. ⌄

Check the lamp or LED module where it is user-replaceable.
Check wall switches, dimmers, pull cords, timers and smart controls.
Inspect the consumer unit for a tripped breaker, RCBO or RCD.
Look for heat, smell, buzzing, water or recent building work.
Attempt one controlled reset only if no danger signs exist.

If operation returns: monitor the light and control.

If the fault remains: leave the affected fitting or circuit off and arrange testing.

1 Fix 1 — Replace the lamp Follow this check without opening live electrical equipment. ⌄

Process

Fit a compatible known-good lamp with the power off.

Success looks like: The light works normally.

Failure means: If not, the fitting, switch or supply needs testing.

2 Fix 2 — Check the consumer unit Follow this check without opening live electrical equipment. ⌄

Process

Look for a tripped breaker, RCBO or RCD and reset once.

Success looks like: The light returns and the device stays on.

Failure means: If it trips again, leave the circuit off.

3 Fix 3 — Check controls and isolators Follow this check without opening live electrical equipment. ⌄

Process

Confirm dimmers, pull cords, wall switches and local isolators are correctly set.

Success looks like: The control restores operation.

Failure means: If controls appear normal, fixed testing is needed.

⌁ Common causes explained Why the fault may happen. ⌄

A light that does not work may have a failed lamp, tripped breaker, faulty switch, loose fitting connection, failed transformer or LED driver, or a wider circuit fault.

Lighting faults can be simple lamp failures or signs of loose connections, failed controls and water ingress. Heat, crackling and repeated protective-device operation require prompt investigation.

⌘ Advanced diagnostics Technician-level testing for a competent electrician. ⌄

Prove dead before opening fittings.
Test voltage at switch and fitting.
Check switched live and neutral continuity.
Inspect lampholders, drivers and transformers.
Test insulation resistance after repeated protective-device operation.

▣ Parts that may need replacing Common failed components linked to this fault. ⌄

Lamp or LED module
Light fitting
Switch
LED driver
Transformer
Cable or junction

! When to call an electrician Conditions that should end DIY troubleshooting. ⌄

The switch or fitting is hot, burnt, buzzing, crackling or sparking.
A breaker or RCD repeatedly trips.
Water may have reached the fitting, switch or cable.
Several lights are affected and lamp replacement does not help.
The fitting is sealed, permanently wired or mounted at unsafe height.
Recent drilling or building work may have damaged a cable.

? Frequently asked questions Common questions about lighting faults. ⌄

Can a light fail without tripping the breaker?

Yes. Lamps, drivers, switches and local connections can fail while the circuit remains energised.

Why does a new LED lamp still not work?

The driver, dimmer, switch, fitting or circuit supply may be faulty or incompatible.

Is flickering dangerous?

It can be harmless incompatibility, but flickering with heat, buzzing or several affected lights may indicate a loose connection.