Why do my lights flicker? Harmless, or a warning

Quick answer

Flickering lights sit on a spectrum. At one end is a single LED lamp that stutters on a dimmer — usually just a globe that doesn’t match the dimmer, and completely harmless. At the other end are lights that dim across the whole house, flicker when the aircon kicks in, or come with a faint buzz or a warm switch plate — and that can mean a loose connection quietly arcing behind the wall, which is a genuine fire risk. Knowing which end of the spectrum you’re on is the whole game. Here’s how to tell.

The harmless one: a mismatched LED

By far the most common flicker I get asked about across Coburg and the inner north is a single downlight or lamp that flickers or stutters, almost always on a dimmer. When Australian homes swapped halogen globes for LEDs, a lot of the old dimmers stayed on the wall. The problem is that old dimmers were designed for the steady, heavy draw of a halogen, and an LED draws a tiny fraction of that in quick pulses. The dimmer can’t regulate it smoothly, and you get flicker.

The fix is genuinely a homeowner one: replace the globe with a dimmable LED that’s rated as compatible with the dimmer you’ve got, or have the dimmer swapped for an LED-compatible one. Swapping a plug-in or screw-in globe is safe. If a proper compatible globe doesn’t settle it down, the cause is something else — and that’s where it stops being a globe problem.

Two quick things help you tell a globe fault from a wiring fault before you call anyone. First, is it one light or several? A single fitting flickering while everything else is steady points at that fitting or its globe. Several lights, or a whole room, points upstream at the circuit. Second, does it track with anything — a dimmer setting, a particular time of day, an appliance switching on? A flicker that only happens on a low dimmer setting is almost always the globe-and-dimmer mismatch. A flicker that comes and goes on its own, or worsens, is the pattern that deserves an electrician. Integrated LED fittings, where the LED and its driver are sealed into the unit, add one more possibility: a failing driver, which needs the whole fitting replaced rather than a globe — still an electrician’s job on a hard-wired fitting.

The one that matters: a loose connection

This is the flicker to take seriously. Every electrical connection in your home — at a light fitting, a power point, a junction box, or on the switchboard — is meant to be tight. When one works loose, the current has to jump a tiny gap, which makes it arc. Arcing shows up as flicker, and it generates heat exactly where you don’t want it: inside a wall cavity or a ceiling, against timber and insulation. That’s how a loose connection becomes a fire.

The tell-tale signs that flicker is a connection problem rather than a globe problem:

• it affects several lights, or dims the whole house, not one lamp;
• it comes with a buzzing or crackling sound at a switch, fitting or the board;
• there’s heat, discolouration or a burning smell at a switch plate or power point;
• it’s getting worse over days or weeks.

Energy Safe Victoria is direct about this: if you have dull or flickering lights, a “brown out”, low voltage or partial supply, you should not touch your switchboard or anything metal in the home — you arrange a licensed electrician. A loose connection is not something to open a fitting and investigate, because the fault that’s making it flicker is the same fault that can shock you.

The appliance dip

A third pattern is lights that dim for a moment when something big starts — the ducted aircon compressor, a pool or bore pump, a workshop motor. Those pull a large surge of current for a fraction of a second as they start, and if the circuit or the switchboard is already close to its limit, the voltage sags briefly and the lights dip with it.

An occasional, slight dip can be normal. A pronounced one, or one that’s becoming more noticeable, usually means the load on that part of the installation is too high for how it’s wired — often an older board that was never specified for a modern household running aircon, induction and fast-charging all at once. That’s frequently a switchboard upgrade rather than a lighting problem, and it’s worth having the circuit load looked at.

The supply-side flicker

Sometimes it isn’t your wiring at all. If the flicker hits the whole house, or you notice it in neighbouring houses too, the cause can be on the network side — the distributor’s supply into the street. That’s not a job for your electrician; it’s one to report to your distributor. A licensed sparky can quickly confirm whether the fault sits inside your installation or upstream of your meter, which saves you chasing the wrong thing. On the older streets around Melbourne’s north, deteriorating household wiring is also a real contributor, and Energy Safe Victoria’s guidance on household wiring is worth a read if your home hasn’t been assessed in years.

What to do next

If it’s one lamp on a dimmer, try a compatible dimmable LED — that solves most flicker with a single compatible globe and no call-out needed. If the flickering spreads across lights, tracks with your appliances, keeps getting worse, or brings any buzz, heat or smell with it, treat it as a wiring fault and stop there. Thunderman does fault-finding, switchboard work and electrical repairs across Greater Melbourne — Yiannis holds REC 28523 with Energy Safe Victoria. Call 0434 254 474 or send a quick message for a free quote.

Sources

• Energy Safe Victoria — Electrical emergencies ↗
• Energy Safe Victoria — Household wiring ↗
• AS/NZS 3000:2018 — Wiring Rules