Why are my lights pulsing instead of flickering?

A regular pulse usually points to a component that is cycling — such as a failing LED driver, an incompatible dimmer trying to regulate the bulb, or a loose connection arcing at regular intervals. It is more systematic than random flickering.

My lights pulse even when switched off — is that normal?

No. If lights glow or pulse when the switch is off, it usually means the switch is breaking the neutral instead of the live, or there is a small leakage current through the switch. This is a wiring fault that needs correcting.

Could a smart bulb cause pulsing?

Yes. Smart bulbs have their own electronics and can pulse if they lose connection to the hub, have a firmware issue, or are on a dimmer switch that is not fully compatible.

Is pulsing worse than flickering?

They both indicate a fault, but regular pulsing from a loose connection can be more concerning because it means the connection is arcing repeatedly at regular intervals, generating heat each time.

Caution

Updated 30 August 2026

Lights Pulsing On And Off

Your lights are rhythmically pulsing — getting brighter and dimmer in a steady, repeating pattern.

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What's happening?

Lights that pulse rhythmically (rather than flickering randomly) often indicate a specific electrical issue such as a failing component, a loose connection that is arcing at regular intervals, or electrical interference. The regular pattern distinguishes this from random flickering and can help pinpoint the cause.

What usually causes it?

Failing LED driver producing unstable output
Incompatible dimmer switch cycling the power to the bulb
Loose connection that is arcing and cooling in a regular pattern
Faulty smart bulb or smart switch with a connectivity issue
Electrical interference from a nearby device on the same circuit
Transformer failing in a low-voltage lighting system

Is it dangerous?

Pulsing lights are more concerning than a simple flicker because the regularity suggests an active and ongoing fault rather than a one-off event. A connection that is arcing rhythmically is generating heat each time and is a fire risk. If the pulsing is rapid and continuous, turn the light off and get it checked.

Can I fix it myself?

Try replacing the bulb first — a failing LED driver is a common cause. If you have a dimmer, check whether the pulsing stops with the dimmer set to full brightness. For smart bulbs, check the app for firmware updates or try re-pairing the bulb. If the pulsing affects multiple lights, the issue is likely in the circuit or consumer unit and you should not attempt a fix yourself.

When should you call an electrician?

Call an electrician if replacing the bulb does not fix the pulsing, if multiple lights are affected, if the pulsing is accompanied by buzzing or a burning smell, or if the lights pulse even when the switch is turned off (which can indicate a wiring fault or a switch that is not fully breaking the circuit).