Why Are My Lights Flickering? 7 Causes, Ranked by How Serious They Are

Byron Knight, Licensed Electrical Contractor

QLD Lic. 1511406 · 20+ years’ experience · Gold Coast & SEQ · Updated September 2026

Most flickering is harmless. Some of it is the earliest warning sign of a fault that starts fires inside wall cavities. The frustrating part is that from where you’re standing they look identical — a light that won’t sit steady.

So rather than another flat list of causes, here they are ranked by how much they actually matter, along with the one diagnostic detail that tells you roughly where in the system your fault sits before anyone opens anything up.

First: the pattern tells you where to look

Before working through causes, note which lights are flickering. This single observation narrows the field more than anything else you can do without test equipment.

That third row is the one that matters. Whole-house flickering is not a bigger version of one-light flickering — it’s a structurally different problem, and it’s the one at the bottom of the list below.

The 7 causes, least to most serious

Ranked by risk of harm, not by how often each turns up. The common ones sit at the top; the dangerous one sits at the bottom.

1. Loose or failing globe. The most common cause and the easiest fix. Bayonet fittings in particular work loose as the fitting heats and cools. If it’s one light and the flicker changes when you gently nudge the globe, you’ve likely found it.
2. Incompatible dimmer. Old leading-edge dimmers were built for halogen loads and generally don’t play well with LED drivers, producing flicker, buzzing, or a narrow usable dimming range. Annoying rather than hazardous — more on this in halogen versus LED downlights.
3. Failing LED driver. Integrated LED fittings have a driver that eventually fails, often flickering for weeks before it goes entirely. A component at end of life, not a wiring fault — though on an integrated fitting it usually means replacing the whole unit rather than a globe.
4. Voltage dip when a large appliance starts. Air conditioners, pool pumps and washing machines draw a surge on startup, and a brief slight dim as they kick in is normal. What isn’t normal is a pronounced dip, a long one, or one getting worse over time — that suggests the circuit is closer to its limits than it should be.
5. Supply-side voltage fluctuation. Sometimes the instability arrives at your property rather than originating in it. See the section below for what the limits actually are and who to call. A quick check: ask a neighbour whether they’re seeing it too.
6. Overloaded circuit. Too much load on one circuit produces voltage sag under demand, and sustained overloading generates heat in the wiring. Rarely an emergency today, reliably a problem eventually. Often shows up alongside breakers tripping, and it’s a common trigger for a switchboard upgrade.
7. Loose neutral or degraded connection. The one that matters. A loose or deteriorating neutral destabilises voltage across everything downstream, and the loose joint itself arcs — generating localised heat capable of melting insulation and igniting surrounding material. It typically presents as flickering across multiple rooms at once, often with appliances behaving strangely at the same time. This needs a licensed electrician now, not at the next convenient appointment.

Why a loose neutral is the one worth understanding

The neutral is the return path for current. When that connection degrades — a corroded terminal, a screw that’s backed off over years of thermal cycling, a joint that was never quite tight — the current still flows, but unstably. Voltage downstream swings rather than holding steady, which is what you see as flicker.

Two things make it genuinely serious rather than merely annoying. The loose joint arcs, and arcing generates concentrated heat at exactly the point where wiring insulation is trying to do its job — the same mechanism behind a switchboard that buzzes or hums. And the voltage instability it creates can push appliances outside their design range, which is why a loose neutral often announces itself through electronics behaving oddly rather than through the lights alone.

The tell is simultaneity. A fridge cycling off and restarting, a TV rebooting, a microwave losing its clock — all at the same moment the lights dip. People usually file these as three separate annoyances. Occurring together, they point to one upstream fault.

Thermal cycling is also why the fault is intermittent and maddening to pin down: connections expand when warm and contract when cool, so a marginal joint can behave for days and then misbehave on a hot afternoon. That’s not a reason to wait and see whether it settles — it’s the reason it needs test equipment rather than observation.

If there’s a burning smell involved, treat that as the priority signal — what to do about a burning smell from a power point covers the immediate steps.

When it’s the supply, not your wiring

Queensland’s Electricity Regulation sets the standard low-voltage supply by reference to the nominal voltage in AS 60038, and has done since 27 October 2018 — before that it was 240 V with a 6% tolerance. For a 230 V nominal supply, the band derived from that standard is commonly stated as roughly 216 V to 253 V.

The practical point is what it means for you: drift outside that band is a network issue rather than a fault in your installation, and no amount of work inside your switchboard will fix it. On the Gold Coast that’s Energex, on 13 62 62 for supply problems. If a neighbour is seeing the same thing, that’s the strongest single indicator you’re on the network side of the meter rather than your own.

What you can safely check yourself

1. Note the pattern — one light, one room, or multiple rooms. Write down what else is running when it happens.
2. Reseat or replace the globe. Turn the light off, let it cool, then try it. If the flicker stops, that was it.
3. Test a dimmer circuit at full brightness for a while. Flicker that only appears when dimmed points to dimmer compatibility rather than wiring.
4. Ask a neighbour. If they’re seeing it too, it’s likely supply-side and worth reporting to Energex.

Anything beyond that — opening fittings, testing connections, touching the switchboard — is licensed work and genuinely not worth attempting. The line is the same as anywhere else in a Queensland home: globe changes are yours, anything involving fixed wiring isn’t, as set out in what you can legally do yourself.

What we check when flicker has no obvious cause

Intermittent flicker is fault finding and troubleshooting work. What that involves:

• Voltage measurement under load — confirming supply sits in the correct range, and watching what it does when demand changes
• Thermal inspection of switchboard terminations — a degrading connection runs hot before it fails, which is exactly what a thermal scan finds
• Neutral integrity testing — checking the return path across circuits rather than assuming it
• Circuit loading assessment — whether the affected circuit is carrying more than it should
• Physical inspection of terminations at fittings, switches and the board itself

Intermittent faults are the hardest category of electrical work to diagnose, precisely because they’re often not misbehaving at the moment someone’s looking at them. That’s what the test equipment is for. Related symptoms worth ruling in or out: no power in one room, or power points dead with the lights still on.

On the Gold Coast, specifically

Two patterns turn up more here than the national picture would suggest. Coastal air corrodes terminations, so in beachside homes through Palm Beach, Currumbin and Mermaid Beach, the “joint that was never quite tight” version of a loose neutral arrives sooner than it would inland — the same mechanism as switchboards corroding faster near the water.

The other is seasonal. Storm season through summer brings network instability and surges, so house-wide flicker during a storm that clears when the weather does is usually the network. House-wide flicker that persists after the storm passes is not, and that distinction is worth holding onto.