Why a light keeps flickering and what it means

Is the bulb actually compatible with the dimmer

Old dimmer switches were built for incandescent or halogen bulbs, which draw a steady load. LED bulbs draw very little power and switch on and off many times a second as part of how they work, and many older dimmers cannot handle that low a load cleanly. The result is flicker, especially at the low end of the dimmer's range.

The fix is usually to check the bulb packaging for «dimmable» and to match it with a dimmer rated for LED loads, not just the old rotary type inherited from a previous renovation. If you have swapped incandescent bulbs for LEDs in an old fitting and the flicker started right after, this is the first thing to suspect.

Is the bulb properly seated in the socket

A bulb that is not screwed in fully makes intermittent contact, and even a small gap causes flickering that gets worse when someone walks past or a door closes, because the vibration briefly breaks the connection. This is the simplest possible fault and costs nothing to check.

Turn the light off, let the bulb cool if it has been on, and screw it in a little further by hand. If the flicker stops, that was it. If it starts again after a day or two, look at the contact tab inside the socket: on older fittings it can be pushed slightly flat or corroded, and gently bending it up with a small screwdriver, with the power off, often solves it.

Is it just one light flickering, or several at once

One light flickering on its own almost always points to the bulb, the fitting, or the dimmer, as above. It is a local problem and rarely dangerous.

Several lights flickering together, especially on different circuits or in different rooms, is a different situation. It often points to a loose neutral connection somewhere upstream, sometimes in the consumer unit itself, and can get worse when a large appliance like a kettle, washing machine or oven switches on and pulls current through the shared circuit.

What is actually dangerous and what not to attempt yourself

A loose neutral connection is not just annoying, it can cause voltage to swing unpredictably across a circuit, which can damage appliances and in some cases cause overheating at the loose joint. If flickering across multiple lights coincides with a burning smell, warm switches or sockets, or visible scorch marks, treat it as urgent and stop using that circuit.

Do not open the consumer unit, take fittings apart beyond changing a bulb, or start testing wiring with a bulb still in place. Mains wiring stays live even when a switch is off in some fault conditions, and identifying a loose neutral or a failing connection needs proper testing equipment and training.

• Burning smell near a switch, socket or the consumer unit
• Lights flickering together with a dimming or browning of colour
• Warm or discoloured switch plates or socket covers
• Flickering that gets worse when a large appliance switches on
• Any sign of scorching on a fitting or plug

When to call an electrician and what to have ready

If you have checked the bulb, the dimmer compatibility and the socket contact and the flicker is still there, or if it involves more than one light, it is worth having a qualified electrician look at it rather than guessing further. We carry out electrical work from 49 € an hour, with a call-out fee of 25 € within Tallinn that is deducted from the bill if the job goes ahead.

Before calling, note which lights are affected, whether it happens at a particular time or with a particular appliance running, and roughly how old the wiring or consumer unit is if you know it. If the fitting itself is old or damaged rather than the wiring, a straightforward light fitting installation starts from 40 € per job and is often the simplest way to close the case.