Most people use brownout and blackout interchangeably. They aren’t the same thing, and the difference matters when it comes to your appliances. A blackout is a total loss of power. A brownout is reduced voltage; the lights stay on, but everything underperforms, and the damage profile is completely different.

If you’ve ever had a fridge die in the weeks after a long, hot summer, there’s a fair chance a brownout was part of the reason.

What is a blackout?

A blackout is a total loss of electricity to an area. The grid stops delivering power to your property entirely. Lights off, appliances off, nothing running.

Blackouts can last anywhere from a few seconds to several days. Duration depends entirely on what caused the outage and how long it takes to repair.

Common causes of blackouts include:

• Severe weather: storms, lightning strikes, flooding, and cyclones can damage power lines, transformers, and substations
• Fallen trees or debris contacting power infrastructure
• Equipment failures within the grid: transformer faults, switchgear failures, substation faults
• Demand exceeding grid capacity during extreme heat events, causing a system-wide collapse
• Vehicle accidents involving power poles

When a blackout occurs, the electricity supply to your area is interrupted at the network level. Your property’s internal wiring isn’t the issue. The power simply isn’t reaching you.

What is a brownout?

A brownout is a partial reduction in voltage, not a complete loss of electricity, but a deliberate or unplanned drop in the voltage level being delivered to your property.

During a brownout, electricity is still flowing. Lights stay on but may dim noticeably. Appliances may run erratically, cycle on and off, or perform below normal capacity. The electrical system is working, just under reduced power.

The term comes from the visual effect: incandescent globes dim to a brownish-yellow colour rather than going completely dark.

Signs you’re experiencing a brownout:

• Lights dimming or flickering without going out entirely
• Air conditioners or refrigerators cycling on and off
• Computers restarting unexpectedly
• Intermittent internet or modem dropouts
• Appliances running at reduced speed or performance

Brownouts typically last minutes to a few hours. Once electricity demand drops or the grid stabilises, normal voltage is restored.

What causes a brownout?

Brownouts come down to demand. When more electricity is being pulled from the grid than the network can comfortably push out, voltage drops across the affected area. The grid hasn’t failed. It’s just being asked to do more than its current state allows.

February is the worst month for it in Brisbane. A run of forty-degree days, air conditioning load through the roof across the city, and the grid working flat out to keep up. That’s the environment where voltage starts to sag. The network operator may then deliberately reduce voltage to keep the whole system from tripping into a full blackout, or manage brownouts as a protective measure.

Energex, the DNSP (Distribution Network Service Provider) responsible for South East Queensland, manages this kind of load shedding as a protective measure for the broader grid. Allowing voltage to drop slightly across a wider area is preferable to losing power entirely for a smaller area.

Factors that typically contribute to brownout conditions in Brisbane and SEQ:

• Peak summer demand when air conditioning load is high across the region
• Severe weather is degrading the infrastructure before a full fault occurs
• Rapid increases in demand that outpace the grid’s ability to distribute power evenly
• Localised infrastructure constraints in older suburban networks

Unplanned brownouts can also result from faults or degradation in the electrical system at the transformer or substation level — not a deliberate action, but a symptom of a stressed or failing component.

How brownouts and blackouts differ: a direct comparison

The key distinction: a blackout means no power. A brownout means reduced power. Both can damage appliances, but they do so in different ways.

What damage can a brownout cause?

Brownouts get underestimated because the lights are still on. The damage they do is slower and less obvious than a blackout-related surge, but the cost adds up.

Anything with an electric motor takes the brunt of it. Motors are designed around a specific voltage. Feed them less, and they pull more current to make up the shortfall, and that extra current turns into heat inside the windings. Motors hate heat. A fridge compressor or an aircon condenser running through a few hours of low voltage might come out the other side fine, but the windings have been cooked a little. Do that across enough brownouts, and the motor packs it in years before it should have.

Computers behave erratically during a brownout. Spontaneous restarts are common. Data corruption is the worst-case version of the same problem: voltage drops below the threshold the power supply needs to maintain a stable output, the system loses state mid-operation, and whatever was being written gets mangled.

The other thing worth knowing: when voltage returns to normal after a brownout, the transition isn’t always clean. A surge can ride in on the back of the restoration, and anything plugged in catches it. That’s the moment televisions die.

Australian wiring rules under AS/NZS 3000 assume appliances will run within roughly 10% of the nominal 230V supply. Brownouts can push voltage below that floor for long enough to matter.

What damage can a blackout cause?

During a blackout, the damage risk comes primarily at the point of restoration, not during the outage itself.

When electricity returns after a complete outage, voltage doesn’t always ramp up gradually. In some cases, the restoration event introduces a surge, a brief spike in voltage that travels through the circuits in your home or business. Appliances left switched on and plugged in during the outage receive that surge directly.

Repeated exposure to restoration surges shortens the lifespan of appliances with electronic controls and can cause immediate failure in sensitive equipment like televisions, computers, and audio equipment.

There’s also a practical safety consideration: if the blackout was caused by a fault at the property level, not a network outage, then restoration without identifying and rectifying the fault first creates a risk of further damage or fire.

Is the problem in the street or in your home?

This is the first question to answer when your power goes out. The answer determines whether you call Energex or a licensed electrician.

Check your switchboard first

If a circuit breaker has tripped or a safety switch (RCD) has operated, the issue is likely inside your property: a fault on a circuit, an appliance drawing excessive current, or a wiring problem. Reset the RCD and see if power is restored. If it trips again immediately, leave it off and call an electrician.

Check the Energex outage map

Energex maintains a live outage map at energex.com.au, where you can enter your address and see whether a network fault is recorded in your area. If there’s a confirmed outage, the issue is at the network level, and Energex crews will be working to restore it. To report an unrecorded outage or a dangerous situation, fallen power lines, or damaged infrastructure, call the Energex faults line on 13 62 62.

If there’s no network outage recorded and your neighbours have power, the problem is on your property

That’s when you need a licensed electrician. A fault inside your home’s electrical system won’t resolve itself, and working on it without the correct licence and equipment isn’t legal or safe under Queensland’s Electrical Safety Act 2002.

How to protect your property from brownouts and blackouts

The best time to think about protection is before a problem occurs. There are several layers of protection worth considering, depending on the property and budget.

Surge protectors: point-of-use protection

A surge protector absorbs voltage spikes before they reach the device connected to it. They’re the first and most accessible layer of protection for computers, televisions, and home entertainment systems.

Point-of-use surge protectors have limits, though. They protect the specific circuit they’re installed on, and they have a finite capacity; a large surge can overwhelm them. They’re a reasonable starting point but not a complete solution.

Whole-home surge protection at the switchboard

This is the more comprehensive option. A whole-home surge protection device, installed at the main switchboard by a licensed electrician, protects every circuit in the property simultaneously.

When voltage is restored after a blackout, or during a brownout event, the surge protection device at the switchboard intercepts transient spikes before they propagate through the internal wiring. Everything connected to the property’s circuits is covered, including appliances without their own point-of-use protectors.

For Brisbane properties with significant appliance value, or for homes with ducted air conditioning systems and modern kitchen equipment, switchboard-level surge protection is worth the investment. The cost of replacing a ducted air conditioning controller, a smart oven, or a home automation system considerably exceeds the cost of the protection device.

Safety switches: RCDs

A safety switch, or RCD (Residual Current Device), protects people, not appliances. It detects when current is flowing through an unintended path (like a person receiving an electric shock) and disconnects the circuit within milliseconds.

RCDs are a legal requirement in Queensland on power circuits and lighting circuits in new installations and renovations. They don’t protect against voltage surges; that’s not what they’re designed for. But they’re an essential safety layer that should be tested every six months. Press the test button on your switchboard, if the circuit trips and resets cleanly, the device is functioning.

If your property has older switchgear without RCDs fitted, that’s a conversation worth having with a licensed electrician.

Backup generators

A backup generator becomes relevant when blackout duration is a concern. A portable generator handles the basics during a long outage at home. You can keep a fridge cold, run a couple of lights, and charge a phone. Beyond that, you’re stretching what it can do.

Standby generators are a different proposition. They sit permanently wired into the property with an automatic transfer switch, watching the incoming supply. When the voltage drops out, the generator starts within seconds, and the transfer switch hands the load across. The property never really loses power. For commercial sites where downtime costs money, or for anyone running medical equipment that can’t tolerate an outage, that’s the setup that makes sense.

Generator installation, particularly the connection to a property’s switchboard, must be completed by a licensed electrician. Under Queensland’s Electrical Safety Act 2002, connecting a generator to fixed wiring without a licence is unlicensed electrical work, which carries significant penalties and insurance implications. The risk of back-feeding into the network, energising lines that Energex workers believe are de-energised, is also a serious safety hazard that correct installation with an isolation switch prevents.

What to do during a blackout

What you do in the first few minutes of a blackout mostly affects what condition your appliances will be in when the power comes back. Having an emergency kit ready before storm season makes the whole situation easier to manage.

First: unplug the things you care about. Computers, the TV, the stereo, the PlayStation, anything with a screen or a circuit board. The risk isn’t the blackout itself; it’s the surge when the power is restored. Pulling them out of the wall takes them out of the firing line.

Switch the big appliances off at the wall too. Aircon, fridge, washing machine, dishwasher. Hitting the off button on the control panel keeps the electronics live; you need the actual wall switch in the off position to disconnect them properly. If the blackout ends up running for hours, that extra step is what keeps you from finding damaged appliances when you come back to reset everything.

Leave the fridge and freezer shut. A fridge with the door closed will hold a safe temperature for about four hours. A freezer holds longer, sometimes a couple of days if it’s full. Every time the door opens, that window shortens.

Leave one lamp switched on as your indicator. That way you’ll know the moment power’s back without having to guess. Once it’s restored, work through the house, bringing appliances back on gradually, one circuit at a time, fridge first, then aircon, then the rest. Switching everything back on at once creates a load spike that the network really doesn’t need on top of whatever caused the outage in the first place.

Forget the candles. An open flame burning in a house you might fall asleep in isn’t a sensible trade-off when a cheap LED torch or a head torch does the same job without the fire risk. Brisbane homes after a summer storm are not the place to add ignition sources.

If you’re running a portable generator, it goes outside. Always outside. Generator exhaust is carbon monoxide, and people die every year from running them in garages or under verandas because they assumed it was ventilated enough. It isn’t.

Dawson Electric is a licensed electrical contractor working across Brisbane and South East Queensland. If you’ve had a brownout or blackout, leave an appliance behaving oddly; that’s worth a callout. The same goes for any switchboard concerns or if you’ve been thinking about adding whole-home surge protection. Get in touch with the team.

Frequently asked questions

What’s the main difference between a brownout and a blackout?

A blackout is a total loss of power; no electricity is reaching your property. A brownout is a reduction in voltage; electricity is still flowing, but at lower than normal levels. A blackout leaves you with nothing running. A brownout leaves lights on but running dimly, and appliances running poorly or cycling unexpectedly.

Can a brownout damage my appliances?

Yes. Sustained low voltage is particularly damaging to appliances with electric motors, refrigerators, air conditioners, washing machines, and pool pumps. These motors draw higher current under low-voltage conditions, generating excess heat. Sensitive electronics are also at risk, both during the brownout and when normal voltage is restored. A damaged appliance left connected can also affect the rest of your home’s electrical system, so it’s worth having anything that’s behaving oddly checked.

How do I know if it’s a brownout or just my home’s electrical system?

During a brownout, your neighbours will be experiencing the same thing: dimmed lights, reduced appliance performance. Check the Energex outage map or call the Energex faults line on 13 62 62. If there’s no network event recorded and your neighbours have full, stable power, the issue is inside your property and requires an electrician.

Should I unplug my appliances during a brownout?

If the brownout is going for more than a few minutes, yes. Sensitive electronics, TVs, computers, and anything with a processor should come out of the wall. Two reasons: the low voltage itself is rough on them, and when normal voltage returns, there’s a surge risk that comes with it. The fridge and aircon can stay plugged in, but flip them off at the wall switch if the dip keeps going.

Are brownouts common in Brisbane and South East Queensland?

Not common, but not rare either. The risk window is summer, January and February especially. When the heat sits above 35°C for days and the air conditioning load across the region peaks, Energex sometimes has to pull voltage down in parts of the network to keep the whole thing from going over. Most Brisbane households will notice one or two brownouts in a bad summer.

What’s the role of a safety switch vs a surge protector?

Two different jobs. A safety switch, an RCD, exists to prevent electrocution. If current starts flowing somewhere it shouldn’t, like through a person who’s contacted a live wire, the RCD detects the imbalance and cuts the circuit within about 30 milliseconds. That’s fast enough to prevent a fatal shock in most cases. A surge protector deals with a completely different problem. It sits between the supply and your appliances, absorbing voltage spikes before they reach anything sensitive. Most properties should have both fitted; they’re not interchangeable.

When should I call an electrician after a power outage?

A few situations. If you’ve reset the RCD or a circuit breaker and it trips straight back, leave it off and get someone out. Same if there’s any smell of burning around the switchboard or a powerpoint once power’s restored. Appliances misbehaving after a brownout, running rough, cycling oddly, not starting, is also worth a callout, because it usually means something inside them took a hit. And anything visibly damaged on the switchboard or in the wiring shouldn’t wait. If the issue is on the network side rather than yours, that’s an Energex call, not ours.