Written by AJ Electrician Near Me | Published on June 2025
When half your house loses power, the most common cause is a tripped double-pole circuit breaker or a fault on one of the two incoming supply phases at your main switchboard. This situation can affect lights in some rooms, power points in others, or entire sections of the home in a seemingly random pattern.
In this article we cover every likely cause, what you can safely check yourself, which situations require a licensed electrician, and what Sydney and NSW homeowners specifically need to know about their electrical supply setup.
Understand How a House Electrical Supply Works
Most homes in Sydney and across NSW receive a single-phase 230V supply from the grid. However, many larger homes and newer builds in NSW receive a three-phase supply, which splits power across three separate phases.
If your home has a single-phase supply, your switchboard distributes that one phase across multiple circuits. If one section of your switchboard has a wiring fault or a failing component, half your circuits can drop out even though the other half stay live.
In a three-phase home, each phase powers a different group of circuits. If one phase drops out at the street or at your meter box, exactly one-third of your home loses power. This can look and feel like half the house going dark.
Understanding this split is important because it changes what you check first and whether the fault is inside your home or outside with Ausgrid or Endeavour Energy.
Check Your Switchboard First
The switchboard, also called the fuse box or meter board, is always your first stop. Locate it, usually near your front door, in the garage, or on an external wall, and look at the circuit breakers or fuses inside.
- A tripped circuit breaker will sit in the middle position, between ON and OFF, or it may have flipped fully to OFF.
- In older homes with rewireable fuses, a blown fuse wire will look scorched or the wire will be visibly broken.
- A tripped residual current device (RCD) or safety switch will have its test button popped out or the switch flipped to OFF.
- A main switch that has partially tripped can cut power to a large section of circuits at once.
- In three-phase switchboards, one of the phase busbars may have lost connection, dropping all circuits on that phase.
Try resetting any tripped breakers by pushing them fully to OFF first, then back to ON. If a breaker trips again immediately, there is a fault on that circuit and you should leave it off and call a licensed electrician.
AJ Electrician Near Me receives calls about exactly this scenario every week across Sydney, the Central Coast, and regional NSW. It is one of the most common electrical call-outs we attend.
Identify the Most Common Causes of Partial Power Loss
There are several distinct reasons why power disappears from part of a home but not all of it. The table below outlines the most common causes, how to spot them, and whether you can fix them yourself.
| Cause | What You Notice | DIY or Electrician? |
|---|---|---|
| Tripped circuit breaker | One or more circuits dead, breaker in middle or OFF position | You can reset it once. If it trips again, call an electrician. |
| Tripped RCD / safety switch | Multiple circuits dead, RCD switch is OFF | Reset it. If it trips again, unplug appliances and retry. |
| Blown fuse (older homes) | Circuits dead, fuse wire burned or broken | Licensed electrician must replace fuse wire in NSW. |
| Fault on one supply phase | Consistent group of rooms dead, no tripped breakers visible | Electrician or network provider (Ausgrid / Endeavour Energy). |
| Faulty main switch or busbar | Large section of home dead, main switch feels hot | Licensed electrician immediately. |
| Damaged underground cable | Outage follows storms, digging, or tree root activity | Licensed electrician or network provider. |
| Overloaded circuit | Breaker trips when high-draw appliance is used | Reduce load. If persistent, upgrade the circuit. |
Know When the Fault Is with Your Network Provider
Not every partial power loss is inside your home. In NSW, the electricity network is managed by Ausgrid (greater Sydney, Central Coast, Hunter) and Endeavour Energy (south-west Sydney, Blue Mountains, Illawarra, and parts of regional NSW).
A fault on the street-side supply, a damaged street transformer, or a loose connection at the overhead service mast can all cause partial power loss in your home. Here is how to tell the difference.
- Your switchboard looks completely normal with no tripped breakers or RCDs, yet half the home is still dead.
- Neighbours on the same street report similar partial outages at the same time.
- The power loss appeared suddenly without any appliance fault or storm inside your home.
- You have a three-phase supply and exactly one-third of your circuits are dead with no switchboard fault visible.
If you suspect a network fault, check the Ausgrid or Endeavour Energy outage maps online or call their fault lines. They handle street-side infrastructure repairs at no cost to you.
If the fault is confirmed to be on your side of the meter, that is where a licensed electrician like AJ Electrician Near Me steps in.
Compare Repair Costs for Partial Power Loss in NSW
Cost is always a concern. The table below gives realistic price ranges for common repairs related to partial power loss in Sydney and across NSW. Prices are indicative for 2025 and will vary based on access, switchboard age, and travel time.
| Repair Type | Estimated Cost (AUD) | Typical Time on Site |
|---|---|---|
| Callout and fault diagnosis | $120 to $200 | 30 to 60 minutes |
| Replace a single circuit breaker | $150 to $280 | 30 to 45 minutes |
| Replace an RCD / safety switch | $180 to $320 | 45 to 60 minutes |
| Replace rewireable fuses with circuit breakers | $400 to $900 | 2 to 4 hours |
| Full switchboard upgrade | $1,200 to $3,000 | 4 to 8 hours |
| Repair or replace damaged underground cable | $800 to $2,500 | Half to full day |
| Repair loose or burnt busbar connection | $300 to $600 | 1 to 2 hours |
Emergency or after-hours callouts typically add $80 to $200 on top of standard rates in NSW. Getting a clear quote before work begins is always a smart move.
Follow These Safety Steps Before the Electrician Arrives
There are things you can do safely right now while you wait for help. There are also things you must not do. Follow this order carefully.
- Turn off and unplug all appliances in the affected area. This removes potential ignition sources if there is a wiring fault.
- Check your switchboard for any tripped breakers or RCDs and note which ones are off. Take a photo if that helps.
- Do not attempt to reset a breaker more than once if it keeps tripping. Repeated tripping means a live fault is present.
- Do not open the main switchboard enclosure or touch any wiring. In NSW, only licensed electricians can legally perform electrical work.
- Check with a neighbour to rule out a street-side outage before calling your electrician.
- If you smell burning, see scorch marks, or hear buzzing from the switchboard, leave the area and call 000 first, then an electrician.
- Keep children and pets away from the switchboard and any dead power points until the fault is resolved.
These steps protect you, your family, and your property while giving the attending electrician a cleaner picture of what has happened.
Recognise Signs That Your Switchboard Needs an Upgrade
Partial power loss in older Sydney and NSW homes is often a warning sign rather than a one-off event. Many homes built before 1990 still have ceramic fuse holders, no RCD protection, or undersized wiring that was designed for a much lower electrical load than modern households demand.
Under NSW regulations, all new electrical work must comply with AS/NZS 3000 wiring rules. If your switchboard is upgraded or a new circuit is added, RCD protection must be installed on power and lighting circuits. An older board without RCDs is a safety and legal liability.
Watch for these warning signs that a switchboard upgrade is overdue.
- Breakers trip frequently, especially when running multiple appliances at once.
- You have ceramic rewireable fuses instead of modern circuit breakers.
- There are scorch marks, a burning smell, or buzzing sounds near the switchboard.
- Your home has no RCD or safety switch installed.
- The board feels warm or hot to the touch.
- You have added new appliances like EV chargers, split-system air conditioners, or solar and the board has not been assessed.
A switchboard upgrade in NSW typically costs between $1,200 and $3,000 depending on the size of the home and the number of circuits. It is one of the most valuable safety investments you can make in an older property.
FAQs on Power in Only Half of My House
Why does half my house have no power but the breakers look fine?
This usually points to a fault on one incoming supply phase, a failed busbar connection inside the switchboard, or a problem at the street-side supply. If all breakers appear to be in the ON position, contact your network provider first to rule out a grid fault, then call a licensed electrician to inspect the board internally.
Is it safe to keep living in the house with partial power loss?
It depends on the cause. A simple tripped RCD that you have reset safely is low risk. However, if there are scorch marks, burning smells, or a breaker that keeps tripping, you should treat it as a potential fire hazard. Get it inspected by a licensed electrician as soon as possible and avoid using the affected circuits until the fault is found.
Can I reset my own circuit breakers and RCDs in NSW?
Yes. Homeowners in NSW are permitted to reset their own circuit breakers and RCDs. You are not permitted to replace wiring, fuses, breakers, or any other internal switchboard components. Those tasks legally require a licensed electrician. If a breaker trips again after resetting, do not keep resetting it.
How long does it take an electrician to fix partial power loss?
Simple repairs like replacing a circuit breaker or RCD take 30 to 60 minutes on site. Diagnosing an intermittent fault or repairing a damaged underground cable can take several hours. Your electrician should give you a time estimate after the initial fault diagnosis is complete.
What causes half a house to lose power after a storm in Sydney?
Storms are a major cause of partial power loss in Sydney and coastal NSW. Wind can damage overhead service lines where they connect to your home. Lightning surges can blow fuses or trip breakers. Flooding can cause RCDs to trip as moisture enters outdoor power points or subfloor wiring. Always check your switchboard after a storm before calling the network provider.
Will my network provider fix the fault for free?
If the fault is on the network side of the meter, Ausgrid and Endeavour Energy repair it at no cost to you. If the fault is on your side of the meter, including your switchboard, internal wiring, and the service mast, you are responsible for the repair costs. A licensed electrician can clarify which side the fault falls on after inspection.
Wrap Up and Next Steps
Partial power loss is almost always caused by a tripped breaker, a blown fuse, a faulty RCD, or a supply issue on one phase. Most faults are found at the switchboard and can be resolved quickly by a licensed electrician.
Do not ignore recurring power loss or any signs of heat and burning near your switchboard. Early action prevents small faults from becoming serious hazards, especially in older NSW homes that were not built for today’s electrical loads.
If half your house has lost power and you are in Sydney or anywhere in NSW, call AJ Electrician Near Me on 1300 617 337. Our licensed electricians are ready to diagnose the fault, give you a clear quote, and get your home back to full power fast.
