Updated on October 15, 2025
A solar system will save you money on your electricity bills. There’s a lot of potential energy you can harvest from the sun. However, there’s potentially a lot of electricity on the roof. How important are features like rapid shutdown?
At PSC Energy, we feel it’s essential to educate customers about the potential risks that come with solar installations. Electricity can be dangerous in the wrong hands. It’s essential to understand what you’re investing in and the risks associated with that technology.
In this article, you will learn:
- What’s the Difference Between DC and AC Solar Panel Systems?
- What is Rapid Shutdown in a Solar Panel System?
- FAQ: Rapid Shutdown
By the end of this article, you’ll be an expert in the risks of high voltage solar and why rapid shutdown is essential.
What’s the Difference Between an AC-coupled and DC-coupled Solar Panel System?
DC solar installations are solar systems that operate at higher voltage levels than AC solar installations.
What do we mean by DC solar and AC solar?
Alternating current (AC) power alternates in a sinusoidal wave as the electrons wiggle back and forth. Direct current (DC) power flows in a straight line from one polarity to the other without deviating.
Solar panels output DC power. Converting the power your system outputs from DC to AC is necessary because your home and all its appliances run on AC power.
A solar system with DC architecture transforms the DC power into AC power at a central inverter. It’s usually installed on the side of your house near the main switchboard.
A solar system with AC architecture, like a microinverter solar system, transforms the DC power to AC power at the solar panel.
If you’re interested in learning a bit more about solar panels and energy systems, you might want to check out the following article titled, Are Solar Panels Worth It in NSW, Australia? A Price Breakdown for 2025.
What is Rapid Shutdown in a Solar System?
Rapid shutdown mechanisms in solar systems make sure that solar panels stop generating electricity when switched off during emergencies.
It’s necessary because the electricity from the solar panels on the rooftop can’t be effectively switched off.
If the sun is shining on solar panels, they will generate electricity. It’s the purpose of solar panels, isn’t it? A rapid shutdown feature turns off all the panels.
In a DC solar system, you can switch off the electricity coming from the grid to the main switchboard. You can also cut off the electricity coming from the solar panels on the roof at the central inverter.
But as you can see in this illustration, there is a cable running between the panels on the roof and the central inverter. There is 600 – 1,000 volts of DC power still in that wire.
Enphase systems have a rapid shutdown feature that truly turns off each solar panel/microinverter combination in your solar system array.
There is no power coming from the solar system when you flip that switch. The microinverters will automatically shut down any DC power production in case of emergencies like fire or grid failure.
We believe in the DC solar systems that we install, it’s important to note that a solid solar installation will do wonders to protect your home while maximising efficiency.
The DC energy systems we install are Tesla Powerwall 3 and SigenStor by Sigenergy. We take extra precautions when installing these two systems, and they both have rapid shutdown.
Electricity is not always safe, and measures like rapid shutdown make systems much safer.
If you’re interested in learning a bit more about weighing the cost of solar against the cost of the grid, you might want to check out the following article titled, Cost of Solar Panels vs. Cost of Energy from the Grid.
Wrapping Things Up: The Importance of Safety During the Solar Boom
Solar is booming in Australia. Over 30% of rooftops are covered in solar panels. No other country has experienced this much interest and investment in rooftop solar.
If you’re not installing it correctly, or if you’re installing an inferior product, you’re playing with fire. Literally, shoddy workmanship and shoddy products are a fire risk.
The more education everyone (from manufacturers to firefighters to the public) has about this technology and the safety ramifications, the better. Ignoring these fundamentals hurts the integrity of reputable solar installers and endangers customers needlessly with fire risks.
At PSC Energy, we want to educate you. We’ve created this space to help you navigate the hundreds of questions you might have about solar energy and solar installations. We’re here to guide you on your solar journey as we all move Australia to Net Zero by 2050. It’s what we do.
If you’re interested in learning a bit more about solar and battery rebates in NSW, Australia, you might want to check out the following article titled, Ultimate Guide to Australia’s 2025 Solar Rebate and Battery Rebate: Federal and NSW Rebate for Solar.
FAQ: Rapid Shutdown
What is rapid shutdown in a solar system?
Rapid shutdown is a safety feature that lets you de-energise a solar array fast in an emergency. It stops power at the panels or the roof, making responders and homeowners safer.
Why does rapid shutdown matter for safety?
Solar panels make power whenever sunlight hits them. If you only turn off the main switchboard or the inverter, DC voltage can still sit on the roof cables. Rapid shutdown cuts the voltage at the point of initiation, so live conductors are not a hazard.
How is an AC solar system different?
An AC system uses microinverters under each panel. The DC is converted to AC at the panel. The cabling from the roof is standard 230 V AC rather than high-voltage DC. This reduces DC arcing risk on long roof runs.
What happens when firefighters arrive at a house fire with solar?
They look for the shutdown switch and the solar labelling. With rapid shutdown, they can quickly drop the array voltage. This helps them ventilate the roof and apply water without contacting live DC conductors.
Why do firefighters prefer systems with rapid shutdown?
Rapid shutdown lowers roof voltage to a safe level at the source. It reduces shock risk and arc flash risk. It also speeds up access because crews do not need to avoid live rails and conduits.
How does rapid shutdown actually work?
The system includes electronics that watch for a shutdown signal. When you hit the switch or when grid power fails, those devices isolate or disable each panel or string within seconds, effectively collapsing the voltage.
Do microinverters provide true rapid shutdown?
Yes. Microinverters turn panel DC into AC at the module and stop power production when commanded or when the grid is out. Panel-level shutdown means there is no live DC string running across the roof.
Can DC string systems have rapid shutdown, too?
Yes. String systems can add module-level power electronics that drop each panel to a very low safe voltage during shutdown. Without these devices, cutting power at the inverter still leaves high DC on the roof cable.
How much voltage is left on the roof after a shutdown?
With module-level shutdown, each panel drops to a very low safe voltage. Without it, a string can still hold hundreds of volts between the array and the ground-level inverter while the sun is out.
Does rapid shutdown affect energy production?
Not in any meaningful way. Well-designed rapid-shutdown hardware has negligible efficiency loss.
Is rapid shutdown required by law in Australia?
Rules change over time and vary by jurisdiction. Treat rapid shutdown as best practice even when not mandated. Ask your installer to explain how your system will de-energise at the roof during an emergency.
Where is the rapid shutdown switch located?
Installers place the shutdown control near the main switchboard or the solar isolation point. It is labelled clearly. First responders should be able to find and operate it quickly.
How do I know if my quote includes rapid shutdown?
Look for language such as panel-level shutdown, microinverters, or module-level power electronics. Or simply ask your solar installer.
Is an AC microinverter system safer than a high-voltage DC string system?
For roof wiring, yes. AC systems avoid long runs of high-voltage DC that can arc under fault. They also give you panel-level shutdown by design. A high-quality DC system is also safe, provided it has the right hardware and workmanship.
What risks does high-voltage DC pose on a roof?
Potential arc faults from damaged connectors, water ingress, crushed conduit, rodent damage, or poor terminations. DC does not cross zero like AC, so arcs can persist unless you break the circuit at the source.
Will rapid shutdown protect my home during a grid outage?
Yes. When the grid fails, compliant systems stop exporting, and the shutdown function de-energises the array conductors. If you have a battery with backup, your home can run on the battery while the roof remains safe.
Does rapid shutdown change how my battery works?
No. Shutdown manages the array and roof conductors for safety. Your battery continues to charge and discharge under normal conditions. It can provide backup if your system is designed for it.
What labels and documentation should I receive?
You should get a shutdown procedure, a single-line diagram, and compliant safety labels at the meter and switchboard. These help you and first responders operate the system safely.
Does rapid shutdown help with maintenance, too?
Yes. Technicians can work more safely when the array is de-energised at the panel. It reduces accidental contact with live DC and speeds up fault finding.
What brands support panel-level shutdown?
Microinverter systems provide it by default. Some energy systems add module-level devices to achieve the same result. Ask your installer which option they recommend for your roof.
What is PSC Energy’s position on rapid shutdown?
We educate customers on roof-level risks and the value of panel-level shutdown. We design systems that de-energise fast in an emergency, and we explain exactly how your shutdown works before we hand over.
Bottom line: Do I need rapid shutdown?
Yes, if you want the safest practical setup. Rapid shutdown reduces risk for your family and for first responders. It is a simple feature that makes a big difference when seconds matter.
