Flickering Lights: Why Do My Lights Keep Flickering?

The short answer

What usually causes flickering lights?

Flickering lights are usually caused by one of two things: a dimmer that doesn’t suit your LED bulbs, or a loose connection somewhere between the light and your consumer unit. Both are common, and both can be fixed, so if your lights keep flickering there’s no need to live with it.

However, not every flicker means the same thing. Where it happens and when it happens tell an electrician a lot, so this guide walks you through the clues, what you can safely check yourself and when it’s time to call us.

Flickering lights diagnosis: one light, dimmed lights or the whole house

Read the clues

Flickering lights: where it happens tells you a lot

Before anything else, notice which lights are affected and when. For example, one flickering bulb is a very different problem from every light in the house dipping when the kettle goes on.

As a rule of thumb, the wider the flicker spreads, the further back towards the consumer unit or the supply the fault is likely to be.

One lightUsually the bulb, the lampholder or an LED driver

Dimmed lightsUsually a dimmer that doesn’t suit LED bulbs

Whole houseOften a loose connection or a supply problem

The causes

The six most common causes of flickering lights

In our experience, most call-outs for flickering lights come down to the first two on this list.

A dimmer that doesn’t suit LEDs

Most older dimmers were made for filament bulbs. With LEDs, they often flicker, buzz or won’t dim smoothly. If only your dimmed lights are affected, the dimmer module is the most likely culprit.

A loose connection

A loose terminal at the switch, ceiling rose, lampholder or a junction box breaks contact for a split second, so the light flickers. Loose connections also create heat, which is why they need fixing quickly.

Non-dimmable or cheap LED bulbs

A non-dimmable LED on a dimmer will almost always flicker. Similarly, some cheaper LEDs have poor-quality drivers that flicker even on a normal switch.

A failing LED driver

Downlights and LED panels have a small driver that converts mains power for the LEDs. When it starts to fail, the light flickers, strobes or takes a while to come on.

A loose bulb or worn lampholder

Sometimes it’s as simple as a bulb that isn’t fully screwed or pushed in, or a lampholder with worn or dirty contacts.

A supply or neutral problem

If every light in the house flickers, especially when the kettle, shower or oven comes on, there may be a loose connection at the consumer unit, the meter tails or the supply itself.

Dimmers

Why dimmers and LED bulbs don’t always get on

In our experience, dimmers cause more flickering lights than anything else. A dimmer works by chopping up the mains supply. Older leading-edge dimmers were built for high-wattage filament bulbs, so a handful of 5 W LEDs can fall below their minimum load. As a result, the dimmer can’t control them properly, and the lights flicker or even glow faintly when they’re off.

The fix is usually a modern trailing-edge LED dimmer with a low minimum load, paired with bulbs marked dimmable. For example, swapping a single dimmer module often cures a whole room of flickering downlights.

Loose connections

Why a loose connection is the one to take seriously

Flickering lights caused by a loose connection are the ones to act on. That’s because a connection that isn’t tight can arc, and arcing creates heat. Over time, that heat can melt insulation, scorch fittings and, in the worst cases, start a fire.

Warning signs include a buzzing or crackling switch, a warm or discoloured faceplate, a burning smell, or lights that flicker when you touch the switch. If you notice any of these, switch the circuit off at the consumer unit and call an emergency electrician.

Checklist

What to check when your lights keep flickering

Before you call anyone about flickering lights, here are a few safe checks you can do yourself:

First, with the light switched off, make sure the bulb is fully screwed or pushed in
If the light is on a dimmer, check that the bulb is marked “dimmable”
Next, try a different, good-quality bulb in the same fitting
Notice whether the flicker happens when a big appliance, such as the kettle or shower, switches on
Also, ask a neighbour whether their lights are flickering too
Finally, never open a switch, ceiling rose or fitting yourself, because that’s a job for an electrician

If the whole street is affected, the problem is probably with the supply rather than your wiring, so call 105 to report it to your network operator. If your trip switch is also going off, read our guide on why your RCD keeps tripping.

How we fix it

How an electrician fixes flickering lights

Flickering lights can be intermittent, so we follow the same three steps every time.

We look at the pattern

We ask which lights flicker, when it happens and what else is switched on. That alone usually narrows it down to a fitting, a dimmer or the circuit.

We test the circuit

Then we check the dimmer, the bulbs and every connection on the circuit, from the switch and ceiling rose back to the consumer unit.

We fix it and re-test

Finally, we replace or re-terminate whatever is at fault and test again, so you know the flicker has gone for good.

FAQ

Flickering lights FAQs

Should I be worried if my lights are flickering?

A single flickering bulb usually isn’t dangerous. However, flickering together with buzzing, a burning smell, a warm switch or flicker across the whole house should be checked quickly, because it can point to a loose connection.

Are flickering lights a fire hazard?

They can be. The bulb itself rarely is, but a loose connection causing the flicker produces heat, and that can damage cables and fittings over time.

How do I stop my LED lights flickering?

Start with dimmable bulbs and an LED-compatible dimmer. If that doesn’t fix it, the cause may be a failing driver or a loose connection, which needs an electrician.

Why do my lights flicker when the kettle or shower comes on?

A slight, brief dip can happen on any circuit. However, a noticeable flicker every time usually means a loose connection in the consumer unit, the meter tails or the supply, so it’s worth having it tested.

Why do all the lights in my house keep flickering?

When every light flickers together, the bulbs are rarely to blame. Instead, it’s often a loose neutral or connection at the consumer unit or in the supply. If your neighbours are affected too, call 105.

How much does it cost to fix flickering lights?

It depends on the cause. For example, replacing a dimmer is a quick job, while tracing a loose connection takes longer. Send us a WhatsApp describing the problem and we’ll give you a free quote.

Still got flickering lights?

Our electricians find the cause of flickering lights and fix it, from a swapped dimmer to a loose connection behind the switch. See our light fitting repair service, or message us for a free quote.

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Why Do My Lights Keep Flickering?