Why are my lights flickering?
Flicker ranges from a cheap LED lamp arguing with a dimmer, which is annoying and harmless, to a loose connection heating up inside a joint, which is the early stage of a fire. Telling those apart is the whole job.
The harmless causes
Most flicker we are called out to is a lamp and dimmer mismatch. Many LED lamps are not compatible with older trailing edge or leading edge dimmers designed for filament bulbs, and the result is flicker, buzz or a refusal to switch on at low brightness. Swapping to a dimmable lamp rated for the dimmer, or changing the dimmer module, resolves it.
A single loose lamp in its holder, or a cheap lamp reaching the end of its life, also flickers. If the flicker follows the lamp when you move it to another fitting, the lamp is the problem, not the wiring.
- One lamp only, and it follows the lamp when moved: replace the lamp
- Only when dimmed: a dimmer and lamp compatibility issue
- Brand new LEDs in an old fitting: check the lamp is marked dimmable if on a dimmer
The causes that need an electrician
Flicker across several rooms at once, or flicker that coincides with a large appliance starting, points at the installation rather than a lamp. A loose connection at a joint, a ceiling rose, a switch or the consumer unit terminals creates a high resistance point that heats every time current passes through it, and heat at a joint is how electrical fires start.
Old lighting circuits with borrowed neutrals, a common finding in South Wales terraces where upstairs lighting was never touched during a kitchen refit, can also flicker in a way that looks random and is not.
Stop and call someone if you see any of these
These are not wait and see symptoms. Switch the affected circuit off at the consumer unit if you can do so safely, and get a qualified electrician out.
- A burning or fishy smell near a fitting, switch or the fuse board
- Scorch marks, browning or heat damage around a switch, socket or ceiling rose
- Buzzing or crackling from a fitting, switch or the consumer unit
- Lights dimming and brightening across the whole house
- Flicker together with sockets cutting out or breakers tripping
What is safe for you to do
Replacing a lamp with the power off at the switch is fine. Anything behind a faceplate is not, and that includes removing a switch plate to have a look. There is no safe way to inspect a live connection without test equipment and training, and a lot of the damage we repair started with someone having a quick look.
Common questions
Can flickering lights be dangerous?
Yes, when the cause is a loose or overheating connection. Flicker limited to one lamp or one dimmer is usually harmless, but flicker across multiple rooms should be investigated.
Why do my lights dim when the shower or kettle comes on?
A brief dip when a heavy load starts can be normal, but a pronounced or repeated dim suggests a supply or connection issue and is worth testing.
Will new LED bulbs fix it?
Sometimes, if the flicker is a lamp or dimmer compatibility problem. If the flicker affects several fittings on different circuits, new lamps will not fix it.
How do you find the cause?
By testing rather than guessing: continuity and insulation resistance on the circuit, then a thermal and visual check of the joints, switches and board terminals.
How quickly can you get out?
We work 8am to 9pm seven days a week, and anything with a smell or scorching gets treated as urgent.