Storms, surges and ageing switchboards put solar homes at risk. What surge protection can and can't do, why safety switches matter, how DC isolators work and the signs it is time for a licensed electrician to upgrade your protection. A home with solar has more to protect than a standard house: long cable runs from the roof, an inverter full of sensitive electronics and, often, a battery. Two devices do most of the protective work. A surge protection device limits voltage spikes before they reach your equipment, and safety switches, known as RCDs, cut power in a fraction of a second if current leaks to earth, protecting people from electric shock. Add correctly rated DC isolators and you have the basis of a safe, resilient system. Checking or upgrading any of these is always a job for a licensed electrician.
What causes surges in Sydney homes
A surge is a brief spike in voltage, lasting a tiny fraction of a second, that can damage or weaken electronics. The common causes are:
- Nearby lightning. A strike doesn't have to hit your house. Energy induced into overhead lines, and into the long DC cables running from your panels, can travel into the inverter.
- Network switching and faults. Storm damage, fallen lines and reconnection after a blackout can all send spikes through the supply.
- Large equipment inside the home. Motors and compressors switching on and off create smaller, repeated surges.
Summer storms are the obvious risk, but a surge can happen whenever the supply is disturbed. Surges can also wear electronics down gradually, so damage doesn't always show up as an immediate failure.
What surge protection can and can't do
A surge protection device (SPD) sits in the switchboard and diverts excess voltage safely to earth. For solar homes, protection usually works in layers:
- At the main switchboard. An AC surge protection device protects the circuits in the house, including the inverter's AC connection.
- On the DC side. Many inverters include built-in DC surge protection. Where cable runs from the roof are long or the site is exposed, additional DC protection near the inverter may be recommended.
- For data connections. Monitoring cables and network equipment can carry surges too, and can be protected separately.
Two limits are worth knowing. No surge device can protect against a direct lightning strike on the house. And SPDs are sacrificial: each large surge wears them, and many have an indicator window that changes colour once they need replacing. Good earthing is essential, because an SPD can only divert energy if it has a proper path to earth. Surge Protection is listed in our energy market from $390 for a main switchboard device, installed (indicative).
Safety switches: what solar owners should know
An RCD monitors the current flowing out and back on a circuit. If some of it leaks away, for example through a person, it switches off almost instantly. Current wiring rules require RCD protection on the power and lighting circuits in new electrical work, but many older Sydney homes have no RCDs at all, or only one covering the power points.
Solar raises some specific points:
- The right type matters. Inverter and EV charger manufacturers can specify the RCD type suited to their equipment, and EV chargers need protection against DC fault currents, either built in or at the switchboard.
- Tripping in wet weather is a warning. An RCD or inverter that trips during rain can point to moisture in an isolator, a damaged cable or a failing connector. Don't keep resetting it. Have it tested.
- Never bypass a safety switch. If it trips repeatedly, it is doing its job.
- Test regularly. Press the test button on each RCD every few months, following the instructions on the switchboard.
Our Safety Switch & RCD Upgrade starts from $390 per board, installed (indicative).
DC isolators: the switches between your panels and inverter
DC isolators allow the solar array to be disconnected from the inverter for maintenance or in an emergency. Depending on when your system was installed, there may be one beside the inverter, one on the roof near the panels, or both. Panels generate DC voltage whenever light hits them, often several hundred volts in a residential system, and the main switch in your switchboard does not turn that off. Knowing where your isolators are, and keeping the shutdown label readable, helps technicians and emergency services if they ever need it.
Watch for these signs, from the ground or beside the inverter only:
- Cracked, faded or discoloured isolator enclosures
- Scorch marks, melting or a burning smell near the inverter or an isolator
- Water marks or condensation inside a clear cover
- Inverter messages about isolation, insulation or earth faults
If you notice heat damage or a burning smell, don't touch the equipment, keep people away and arrange a licensed technician promptly. If there is smoke or fire, contact emergency services. Our Electrical Safety Inspection ($299 for the solar system and switchboard, indicative) tests isolators, earthing, insulation resistance and RCDs, and includes a written report.
When to upgrade your protection
| What you notice | What it may mean | Sensible next step |
|---|---|---|
| No safety switches, or only one for power points | Lighting and other circuits unprotected | RCD upgrade, possibly with a switchboard upgrade |
| Old ceramic fuses | A board that may not suit solar, battery or EV work | Switchboard assessment |
| Surge device indicator showing replacement needed | Protection already used up | Replace the device |
| Inverter dead after a storm | Possible surge damage | Fault diagnosis and a written report |
| Adding a battery or EV charger | New circuits and protection requirements | Protection designed as part of the quote |
If your board needs more than individual devices, our Switchboard Upgrade starts from $1,490 for a standard residential board (indicative, confirmed after inspection). When we design a residential solar system, we assess the existing protection as part of the site visit.
None of this is DIY work. Switchboards, surge devices, RCDs and isolators all involve live parts, and solar adds DC circuits that stay energised in daylight. In NSW this work must be done by a licensed electrician, who issues a compliance certificate for it. Please don't open the switchboard, remove covers or operate damaged equipment yourself.
Next steps
If your home has solar and you're unsure how well it is protected, request a quote and mention surge protection or safety switches. Our team will inspect the switchboard, isolators and earthing during the visit and recommend only what your home actually needs. If you are considering solar batteries, protection is best planned at the same time.
Frequently asked questions
Will home insurance cover an inverter damaged in a storm?
It depends on your policy. Some home and contents policies cover damage from lightning or power surges, while others limit or exclude it, and fixed solar equipment can be treated differently from appliances. Check the policy wording before making a claim. Insurers usually want a written report from a qualified technician, and our Solar Fault Diagnosis ($249 for the call-out and first hour, indicative) identifies the cause and what a repair involves.
Does a home battery need its own safety switches?
A battery system is installed with its own protection devices under the Australian battery installation standard and the manufacturer's requirements. Circuits supplied by a backup system also need RCD protection, so if essential circuits move to a backup sub-board, those circuits are protected there too. We design this protection as part of every battery quote, so you don't have to work it out yourself.
Will a surge protector stop my solar working during a blackout?
No. Surge protection plays no part in what happens during a blackout. Grid-connected inverters are designed to shut down automatically when the grid fails, so they don't send power into lines that crews may be repairing. If you want power during outages, you need a battery with a backup-capable inverter and the right circuits connected, which is a separate design decision.
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