Why do my LED bulbs flicker with certain light switches – Advice from Electriman, North London Electricians

If your LED bulbs flicker when connected to a particular light switch but work fine elsewhere in the home, the switch itself is almost certainly the culprit rather than the bulb. Here is what is most likely going on and what you can safely check.

The most common cause is an illuminated switch, meaning one with a small glowing indicator light built into the rocker. These switches use a tiny neon or LED pilot lamp that needs a small bleed current to stay lit even when the switch is off. That tiny current passes through your LED bulb and causes it to flicker or glow faintly. Traditional incandescent bulbs were not bothered by this because they needed much more current to show any visible effect, but LEDs are far more sensitive.

Dimmer switches are the second most common cause. Many older dimmers were designed for incandescent or halogen bulbs and use a trailing-edge or leading-edge chopping method that simply does not suit modern LED drivers. Even dimmers sold as LED-compatible can still cause problems if the total wattage on the circuit is too low, since most dimmers require a minimum load to function correctly.

What you can check yourself:

1. Look at the switch and see whether it has a small glowing dot or indicator light when the lights are off. If it does, that is very likely the cause.

2. Check whether the flickering happens at all brightness levels or only when dimmed low.

3. Try the same LED bulb in a different switch

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Electriman covers Mill Hill, Barnet, Finchley, Edgware, Enfield, Watford and surrounding areas. All work is Part P certified and fully insured.