Why Are My Lights Flickering?

What Is a Lights Flickering Problem?

Occasional flickering when a large appliance starts up — like a pool pump, geyser, or air conditioner — is usually not a concern. This is caused by a momentary voltage dip as the motor draws high starting current, and it's common in South African homes, especially those with older wiring or undersized circuits.

Persistent flickering, flickering in multiple rooms, or lights that dim and brighten irregularly are a different matter. These patterns often point to a loose connection somewhere in the circuit — either at the light fitting, in a junction box, at the DB board, or in the cable itself.

Loose connections are the most common cause of house fires in South African homes. A connection that arcs intermittently generates enough heat to ignite surrounding materials, and the flickering you see is often the only early warning sign.

Common Symptoms & Warning Signs

• Lights flicker briefly when the washing machine, geyser, or pool pump switches on
• Lights flicker continuously or irregularly with no obvious cause
• Flickering affects multiple rooms or the whole house simultaneously
• Lights dim noticeably when certain appliances are in use
• A specific light fitting flickers even after the bulb is replaced
• LED lights flicker but older incandescent bulbs didn't in the same fitting
• Flickering worsens at certain times of day or during hot weather

What Causes a Lights Flickering Issue?

• Loose connection at the fitting or switch: Vibration and thermal cycling over time cause wire terminals to loosen
• Faulty or incompatible LED driver: Some LED bulbs are not compatible with older dimmers or light circuits designed for incandescent loads
• Overloaded circuit: Too many lights or appliances on one circuit causing voltage fluctuation
• Loose main connection at DB board: A loose neutral or live connection at the board affects all circuits simultaneously
• Faulty light switch: An aging switch with worn contacts causes intermittent connection
• Voltage fluctuation from Eskom supply: Poor supply quality from the grid, more common during heavy load periods

Flickering that is limited to a single fitting is usually a local fault. Whole-house flickering always warrants professional investigation as it suggests a fault at or before the DB board.

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How Urgent Is This?

LED flickering caused by bulb incompatibility with a dimmer is low urgency — it's annoying but not dangerous. However, any flickering caused by a loose electrical connection is medium to high urgency because of the fire risk associated with arcing connections.

Whole-house flickering or flickering accompanied by buzzing sounds, warm switch plates, or a burning smell must be treated as high urgency. These are clear signs of an active arcing fault that needs professional attention the same day.

DIY vs Professional Repair

Homeowners can safely replace bulbs and check whether the problem is bulb-specific. If you have a dimmer switch, try a bulb that is explicitly rated as dimmable. Switching off a flickering light at the breaker until it's inspected is the safest course of action.

Investigating connections inside light fittings, junction boxes, or the DB board must only be done by a registered electrician. Even with the switch off, a live conductor may still be present at the fitting depending on the circuit wiring method — a common situation in South African homes wired before modern standards.

What Professionals Actually Do

The electrician will start by testing supply voltage at the affected circuits to identify any voltage variations. They'll check connections at the light fitting, any accessible junction boxes, and the relevant circuit breaker at the DB board — tightening or re-terminating any loose connections found.

If whole-house flickering is present, they'll check the main supply connections and neutral link at the board using a thermal camera or contact thermometer to identify heat from arcing. All repaired connections will be tested under load, and the electrician will advise if an aging DB board or wiring needs upgrading for long-term safety.

Property Damage Risks

Arcing at a loose connection generates temperatures of hundreds of degrees Celsius at the point of contact. In a wall cavity or ceiling void, this heat can ignite timber framing, insulation, or accumulated dust without any visible warning until the fire has already taken hold.

Flickering caused by a failing connection at the DB board can also cause voltage spikes across all circuits in the home, damaging sensitive electronics, smart home devices, and appliances with electronic controllers.

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