Troubleshooting • Electrical • Sydney
Flickering lights are one of the most common electrical symptoms in Sydney homes — and most of the time, the cause is harmless. A loose globe, an incompatible dimmer, or a momentary load change from your aircon kicking in. But sometimes flickering signals a serious wiring fault that needs a licensed electrician. Here’s how to tell the difference, what you can safely check yourself, and when to call.
Why Are My Lights Flickering? When to Call an Electrician
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The Four Most Common Causes of Flickering Lights in Sydney Homes
Dimmer switch + LED incompatibility
The single most common cause. Old trailing-edge dimmers designed for halogen create a rapid on/off cycle with LED drivers, causing visible flicker. The fix is simple: replace the dimmer with an LED-compatible trailing-edge or DALI dimmer. Cost: $80–$150 per circuit, installed. This is a licensed electrician job — dimmers are hardwired into the switch, not plug-and-play.
Large appliance load change
When your ducted air conditioning compressor, pool pump, or electric oven switches on, it draws a momentary surge that causes a brief voltage dip on the circuit. If your lights dim for half a second when the aircon kicks in, that's normal behaviour on a single-phase supply — not a fault. If the dimming lasts more than a second or happens repeatedly, it may indicate an undersized main or loose connection.
Loose or corroded connection
This is where it gets serious. A loose wire at the light fitting, the junction box, or inside the switchboard creates intermittent contact — the light works sometimes and flickers when the connection shifts. This generates heat at the loose point, which can melt insulation, scorch components, or start a fire. If flickering is accompanied by a warm switch plate, a buzzing sound, or a faint burning smell — stop using that circuit and call an electrician immediately.
Ageing or faulty wiring
Pre-1970 Sydney homes sometimes have aluminium wiring, rubber-insulated conductors, or fabric-sheathed cable — all of which degrade over decades. Degraded insulation causes intermittent leakage, poor continuity, and flickering under load. This is a full-rewire situation for the affected circuit, not a quick fix. A licensed electrician can test continuity and insulation resistance to confirm.
What You Can Safely Check Yourself (And What You Cannot)
Safe for you to check
- Is the globe loose? Turn off the switch, wait for it to cool, and gently reseat the globe. If it's a bayonet fitting, push and twist firmly.
- Is the globe failing? If the flickering is on ONE light and the globe is old, try replacing it. Use the same type (LED, halogen) and wattage.
- Is it one room or the whole house? If only one light or one room flickers, the issue is local. If the whole house flickers simultaneously, the cause is supply-side or switchboard — not something you can fix.
- Does it coincide with a specific appliance? If lights dip when the aircon, dryer, or oven starts, it's a load change — probably normal on single-phase.
Do NOT attempt
- Opening a light fitting to check wiring — this is licensed electrical work in NSW
- Opening the switchboard — live 240V+ inside, lethal. Licensed electricians only.
- Replacing a dimmer switch yourself — dimmers are hardwired. DIY is illegal in NSW.
- Ignoring a warm switch plate or burning smell — stop using that circuit and call an electrician immediately.
- Repeatedly switching a flickering light on and off "to test it" — if there's a loose connection, each toggle stresses it further.
When Flickering Lights Signal a Serious Wiring Fault
Flickering lights you can't explain? Don't wait.
If flickering is sudden, widespread, or paired with burning smell, treat it as urgent. SRS provides 24/7 emergency electrician callout across Sydney — licensed, insured, ML 000108002.
Get an Emergency Electrician →A common pattern we see in Sydney fault callouts: the homeowner notices flickering on a kitchen circuit that’s been slowly getting worse. The first month it’s once a week; by month three it’s daily. When we open the junction box behind the powerpoint, we find a loose neutral conductor that’s been arcing intermittently — the wire termination is scorched brown, the insulation is melted back 20mm, and the plastic housing has begun to deform.
That’s a fire path. If the homeowner had ignored it another few months, we’d be looking at an emergency callout instead of a planned repair. The repair itself takes 30–60 minutes and costs $200–$400. The emergency call-out at 11pm after the outlet starts smoking costs $400–$700.
The rule of thumb: flickering that’s getting progressively worse is never “just the globe.”
What a Licensed Electrician Investigates When You Report Flickering
A standard fault-finding appointment for flickering lights takes 30–90 minutes and includes:
- Circuit identification — which circuit(s) are affected, and whether the issue is isolated to one circuit or spans multiple
- Voltage measurement — checking supply voltage at the switchboard and at the affected fitting. Unstable voltage (below 216V or above 253V) indicates a supply-side issue — often an Ausgrid/Endeavour problem, not internal
- Connection inspection — opening the affected light fitting, junction boxes, and switch points (with power isolated) to check for loose, corroded, or heat-damaged terminations
- Insulation resistance testing — using a megger to measure the insulation quality of the circuit wiring. Low readings indicate degraded insulation that needs replacement
- Dimmer compatibility check — if LEDs are installed, confirming the dimmer type matches the LED driver requirements
- Switchboard inspection — checking the main switch, neutral bar, and circuit breaker connections for tightness and signs of heat
Most flickering faults are resolved in a single visit. Wiring replacement (if degraded insulation is found) may require a return visit. An electrician will give you a written quote before any additional work starts.
Primary sources: SafeWork NSW electrical hazards.
Frequently Asked Questions
Why do my lights flicker when the air conditioner turns on?
When a large appliance like ducted aircon starts, its compressor draws a surge of current that momentarily dips the voltage on your circuit. This causes a brief dim or flicker on lights sharing the same supply. On a standard single-phase Sydney home with a 63A main, this is normal behaviour — not a fault. If the dimming lasts more than 1–2 seconds or happens on every cycle, it may indicate an undersized main or a loose neutral connection.
Are flickering LED lights dangerous?
Usually no — LED flicker is most often caused by an incompatible dimmer switch, not a wiring fault. Replace the dimmer with an LED-compatible trailing-edge model and the flicker stops. However, if the flickering is accompanied by warmth at the switch, a burning smell, or buzzing, it's a wiring issue — call a licensed electrician.
Can I fix flickering lights myself in NSW?
You can replace a globe and reseat a loose bayonet fitting. Everything else — opening light fittings, replacing dimmers, checking wiring, opening the switchboard — is licensed electrical work in NSW. DIY electrical work is illegal, voids your insurance, and is genuinely dangerous.
How much does it cost to fix flickering lights in Sydney?
A standard fault-finding visit costs $150–$300 (during business hours). If the cause is a dimmer swap: $80–$150. If it's a loose connection: $200–$400. If degraded wiring on a circuit needs replacing: $500–$1,500+. Most flickering faults are resolved in a single visit for under $400.
Should I call an emergency electrician for flickering lights?
Only if the flickering is accompanied by a burning smell, warm switch plate, buzzing/crackling noise, or visible smoke. Those symptoms indicate an active fault generating heat — a genuine emergency. Simple flickering without those symptoms can wait for a next-business-day appointment.
Why do my lights flicker only at night?
Night-only flicker usually means the issue is load-related — your home draws more power in the evening (cooking, heating, entertainment) and the additional load exposes a marginal connection or an undersized circuit. It can also be caused by neighbourhood load: when the street draws more from the Ausgrid network at peak times, your supply voltage drops slightly.
Flickering lights that won't stop?
If it's getting worse, smells wrong, or feels warm — don't wait. A 30-minute fault-find from a licensed electrician tells you exactly what's happening and what it costs to fix.