A single lightning strike on the grid can fry every device plugged into your home in a fraction of a second. Surge protection is the difference between a power flicker and a five-figure replacement bill.
A single lightning strike on the grid can fry every device plugged into your home in a fraction of a second. Surge protection is the difference between a power flicker and a five-figure replacement bill.
Surge protection sits in the same category as smoke alarms and safety switches. You do not notice it doing its job until the day it saves you thousands of dollars. Most Sydney homes still do not have it.
This guide explains what a surge actually is, where they come from in the Sydney grid, what a whole-of-house surge protector does at the switchboard, the difference between switchboard and powerpoint level protection, and the maintenance schedule a properly installed unit needs.
A power surge is a sudden spike in mains voltage, well above the normal 230 volts that Sydney homes run on. Spikes range from small noise pulses of a few hundred volts up to direct or indirect lightning strikes that can momentarily put thousands of volts on the supply.
Most surges last microseconds. That is long enough to fry the power supply of any device that does not have its own protection. Televisions, computers, modems, smart appliances, LED drivers, induction cooktops, and EV chargers are all vulnerable. The damage can range from a single fried capacitor to a fully bricked device that needs replacing.
Lightning is the obvious one. A direct strike on a power line or a nearby strike that induces a current in the network can send a massive surge into every house downstream. Sydney's summer storm season delivers dozens of these every year.
Network switching is the less obvious cause. When Ausgrid switches load between substations, restores power after an outage, or rolls a fault response across the grid, the resulting voltage transients can be just as damaging as a small lightning strike. These happen multiple times per month in most Sydney suburbs.
A surge protective device, or SPD, sits inside the switchboard. When a voltage spike comes down the mains, the SPD shunts the excess energy to earth before it reaches the rest of the house. The protection works in microseconds, faster than any single appliance protection.
Modern SPDs are three-stage devices. Stage one handles the big lightning strikes. Stage two handles moderate spikes from network switching. Stage three smooths the smaller noise pulses that wear down sensitive electronics over time. Together they protect every circuit in the house, including the ones nothing is plugged into.
Powerpoint level surge protection, the kind built into a surge-protected power board, is fine for individual devices but it cannot protect the whole house. Anything not plugged into a protected board, including the oven, the air-con, the EV charger, and the hot water service, is unprotected.
Switchboard level protection covers every circuit at the source, before the surge reaches any outlet. For best results, we install both. SPD at the board for the whole house, plus surge boards on AV cabinets and home offices for the extra layer where sensitive gear lives.
A modern SPD has an indicator window on the front. Green means healthy. Red means the device has absorbed a significant surge and needs replacing. Most SPDs will sit green for years, then go red after a single major event. We check the indicator on every annual safety visit.
Replacement is usually under an hour. The new module slots into the same DIN-rail position on the board, and the rest of the protection remains live during the swap. SPDs are designed to be sacrificial, which is the point. They take the hit so your appliances do not.
If your home has an EV charger, ducted air-con, induction cooktop, solar inverter, home network gear, or more than two televisions, a switchboard SPD pays for itself the first time it earns its keep. The unit is modest, the install is short, and the protection runs for years.
For Sydney homes in storm-prone suburbs, exposed coastal positions, or anywhere with frequent grid switching, we recommend SPDs as standard on every switchboard upgrade. It is one of the cheapest single upgrades we install, and one of the highest-value over the life of the home.
If your safety switch is more than ten years old, or it trips for no obvious reason, it is already telling you something.
Most EV owners do not think about their home charger until the car arrives in the driveway. By that point, the install is a rush, and rushed installs go wrong.
Federation cottages, post-war fibros, 1970s brick veneers. They share one thing. Their switchboards were not built for 2026.
Fill in your details below and we'll get back to you within 20 minutes or less.
From blown fuses to full rewires, we're here to power your day.