Lights flicker for two broad reasons: something small and local — a loose bulb, an LED on an incompatible dimmer, or a heavy appliance briefly pulling the voltage down — or something more serious, such as a loose wiring connection, a failing consumer unit or a fault on the incoming supply. One flickering bulb is almost always harmless; flickering across several rooms, or flickering that is new and getting worse, needs an electrician.
Is it one light, one room, or the whole house?
Work out how widespread the flickering is — it’s the single most useful diagnostic question, and the first thing we’ll ask when you call.
- One light flickers. Nine times out of ten this is the bulb, the lamp holder or the dimmer controlling it. Switch the light off, let the bulb cool, then reseat it or swap it for a known-good one — the only hands-on fix you should attempt yourself.
- Every light in one room, or on one lighting circuit, flickers. Once several fittings misbehave together, the bulbs are no longer the likely cause. This points to a connection working loose somewhere on that circuit — inside a switch, ceiling rose or junction box — and it needs an electrician to trace.
- The whole house flickers. Now you’re looking at the main supply: the meter tails, main fuse, consumer unit or the network cable in the street. If your neighbours’ lights are doing the same thing, the fault is almost certainly on the supply side rather than in your wiring.
One important distinction: if lights in part of the house have gone off completely rather than flickering, that’s a different fault with its own set of causes — see our guide to no power in half the house.
Common harmless causes
Most flickering we’re asked about turns out to be one of these:
- A loose or failing bulb. Bulbs work loose with vibration and heat, and both filament and LED bulbs flicker as they reach the end of their life. Changing or reseating a bulb is the one DIY fix that’s genuinely safe — switch the light off first and let it cool. If a new bulb flickers in the same fitting, stop there; the fault is in the fitting or its wiring, and that’s not a DIY job.
- LED bulbs on an incompatible dimmer. Probably the most common flickering complaint in London homes since the switch to LEDs. Older leading-edge dimmers were designed for hot, hungry halogens; LEDs draw so little current that the dimmer can’t regulate them smoothly, so they shimmer or strobe at low settings. Nothing dangerous here — the cure is a trailing-edge, LED-compatible dimmer, a quick and inexpensive swap for an electrician.
- An appliance starting up. A fridge compressor, washing machine heater, electric shower or kettle pulls a surge of current as it kicks in, and the lights dip briefly in sympathy. A short, occasional dim that matches an appliance switching on is normal. If the dip is becoming pronounced, constant or is new behaviour, the circuit may be overloaded or a connection deteriorating — worth a check.
- Cheap or mismatched bulbs. Bargain LEDs with poor internal drivers flicker on perfectly healthy circuits, and mixing bulb types on one dimmed circuit often causes shimmer. Decent branded bulbs of the same type frequently end the problem.
Causes that need an electrician
If you’ve ruled out the bulb and the flickering affects more than one fitting, is getting worse, or comes with any other symptom, one of the following is likely — and none of them is a wait-and-see fault.
- Loose connections in the wiring. The most common serious cause we find. Terminals in switches, ceiling roses and junction boxes loosen over years of heating and cooling; a loose connection arcs, and arcing generates intense heat behind plastic and plaster where you can’t see it. Loose connections are a leading cause of electrical fires, which is why persistent flickering should never simply be lived with. A circuit that flickers and also trips is a particularly strong warning sign — see our guide if your fuse box keeps tripping.
- A failing consumer unit. An ageing fuse board with worn switches, tired terminals or heat damage can cause flickering across the whole house, often alongside buzzing, warmth or discolouration at the board. If a safety device has started playing up as well — for instance an RCD that won’t reset — the installation is telling you it needs professional attention.
- A supply or network fault. A deteriorating main fuse, corroded meter tails or a damaged cable in the street can make every light flicker no matter how sound your own wiring is. If your neighbours are affected too, call 105 — the free national number for your local electricity network operator — and report it. If it’s only your property, the fault is likely at your intake or in your installation, and that’s our job.
When flickering is urgent
Treat flickering as an emergency, not a quirk, if it comes with any of the following:
- A fishy, acrid or hot-plastic smell anywhere in the house — read our burning smell from a socket guide and act on it now
- Buzzing, crackling or sizzling from a switch, fitting or the consumer unit
- Scorch marks, discolouration or warmth on any switch or ceiling fitting
- Flickering combined with circuits tripping, or lights dimming hard whenever anything is switched on
- Flickering that started immediately after building work, a leak or a storm
In any of those cases, switch the affected circuit off at the consumer unit if it’s safe to reach — using only the switches on the front — and call our 24-hour emergency electrician line. Never remove a light fitting, open a switch or take the cover off the consumer unit; changing a bulb is the only fix you should ever do with your own hands.
What our electrician will do
- Ask about the pattern — which lights, when it started, what triggers it — to narrow the fault before touching anything
- Safely isolate and inspect the affected fittings, switches and connection points, checking terminals for looseness and heat damage
- Test the circuit properly — insulation resistance, continuity and polarity — rather than guessing from symptoms
- Check the consumer unit and main intake connections if the flickering is house-wide
- Re-terminate, repair or replace whatever is at fault, then re-test before re-energising so the fix is proven, not assumed
If we find wider problems — several loose connections, ageing cable or a tired fuse board — we’ll tell you plainly and recommend the right next step.
What it costs
Our minimum charge for any visit is £108 including VAT (£90 + VAT), which covers attendance and fault-finding. Prices are labour-only, and most flickering faults — a loose connection, a dimmer swap, a re-termination — are diagnosed and fixed within that first visit. If more work is needed, you get a fixed price quoted before the work starts, never an open-ended hourly bill. As a NICEIC Approved Contractor, we test and certify every repair to current wiring regulations.
Frequently asked questions
Can flickering lights cause a fire?
Flickering itself doesn’t start fires, but its most common serious cause — a loose, arcing connection — absolutely can. Arcing creates intense heat inside walls and fittings long before anything visibly fails, which is why persistent or worsening flickering should be inspected rather than ignored.
Why do my LED lights flicker when dimmed?
Usually because they’re paired with an older leading-edge dimmer designed for halogens. LEDs draw too little current for it to control smoothly. A trailing-edge, LED-compatible dimmer with matching dimmable bulbs cures it in almost every case.
My neighbours’ lights are flickering too. Who do I call?
Call 105, free from any phone. It puts you through to your local electricity network operator, responsible for the supply up to your main fuse. Faults in the street or wider network are theirs to fix, at no cost to you.
Do you cover my area?
We’re based in Tottenham N15 and cover north, east and central London around the clock — see our London service areas page for the full list of postcodes and boroughs.
Flickering lights getting worse? Call us
F & A Electrical is rated 9.69/10 from 237 Checkatrade reviews, and we answer the phone day and night. Call 07407 627542 or 07500 721453 and describe the pattern — we’ll tell you honestly whether it can wait for a booked visit or needs someone out today.