In short
No, a standard grid-connected solar system switches itself off in a power cut, even in full sun, and should restart on its own once the mains has been back for a short while. Having a battery doesn't change that unless the system was designed and wired to give backup power.
The power has gone off, the sun is out, and the inverter shows nothing. Or the lights came back an hour ago and the panels still look dead, and you're wondering whether the storm has broken something.
Do solar panels work in a power cut? Why they switch off
No, and that is by design. A home system connected to the grid under the G98 rules has to disconnect itself when the mains supply fails. The Energy Networks Association's connection guide puts it plainly: "The generating unit will disconnect from the distribution system if your mains power is interrupted" (ENA connection guide).
The reason is the people fixing the fault. If your inverter kept feeding electricity into the street while the network was down, it could put the engineers working on it at risk. The charity National Energy Action says the switch-off "protects engineers working on the fault" (NEA solar PV guide).
The feature is called loss of mains protection, and it is built into the inverter. The G98 standard makes the installer test it on commissioning day by removing the supply and checking the inverter shuts down.
When the power returns, the inverter waits. G98 only lets it reconnect once the voltage and frequency have stayed within safe limits "for a minimum of 20 s". So in daylight your system should start generating again by itself within a few minutes. Panels make nothing in the dark, so after an evening power cut you won't know until the morning.
A battery doesn't change any of this on its own. A standard battery set-up stops with the panels. Only a system designed to separate your home from the grid and run on its own can keep anything going, and NEA notes that "some more expensive battery systems" can do this.
What to check if your solar panels don't work after a power cut
Give it a few minutes of daylight after the power returns. Then work through these in order. None of them needs tools, and none involves opening anything.
Is it the app, not the panels? A power cut switches off your broadband router too, and the monitoring app can show nothing until the inverter is back on the wi-fi.
What to do: Look at the inverter's own screen or your generation meter instead. On most generation meters a red light flashes, and NEA notes "The faster the red light flashes, the more electricity is being produced".
The solar breaker. A power cut or a lightning strike can trip the circuit that feeds the solar. Which? advises switching it back on once, and if it won't stay on: "If it trips back to the off position, leave it off and call an engineer" (Which?).
What to do: Find the breaker marked solar or PV in your consumer unit. Reset it once, and only once.
The inverter display. An error code tells an engineer a lot. Which? notes the code should help show whether the fault is on the AC side (your house and the grid) or the DC side (the panels).
What to do: Take a clear photo of the screen before you do anything else.
The isolator switches. Most systems have two, one at the inverter and one near the consumer unit (Which?). Flicking them on and off to see what happens doesn't help.
What to do: Leave them alone unless you're following the shut-down instructions your installer left you.
Signs of damage. A burning smell or scorch marks after a storm are not things to test yourself. The panels still make electricity in daylight whether the inverter is running or not.
What to do: Turn off the solar breaker, don't touch the inverter or any cables, and call an engineer.
Do you have a battery with backup? Backup needs an inverter with an emergency power supply output and the wiring for it. The usual way is a small set of essential circuits on their own consumer unit rather than the whole house, as battery maker GivEnergy's installer guide shows. A system built to run apart from the grid also falls under the larger G99 rules, not G98.
What to do: If backup is why you want a battery, say so before you buy. Our home battery storage page covers the options, and our G98, G99 and DNO approval guide covers the paperwork.
What we see on real jobs
A fair number of panicked calls about solar that has "stopped" turn out to be a monitoring or wi-fi problem rather than a solar problem. After a power cut that's even more likely, because the router went off too. We would always rather tell you that than sell you a repair you don't need.
When Tony Beckett, our director, talks to homeowners about batteries, it's about using the power later, not about power cuts. In his words, "you can charge your batteries on cheap tariffs in the evening", and "You can use them when the sun goes down". That is what a standard home battery is for, so don't assume it will keep the lights on.
What it costs if the inverter has failed
Sometimes a power cut is just the moment an existing problem comes to light. Inverters are the part most likely to go wrong: in a Which? survey, 15% of owners had had problems with their inverter, by far the most common fault (Which?). Most last between ten and fifteen years, so an older one that won't clear its fault after a cut may simply have reached the end of its life.
A replacement inverter typically costs £1,200 to £2,000 fitted, depending on its size and type. We keep some in stock and source others for the job.
We repair where repair makes sense and replace where it doesn't, and we tell you which before any work starts.
When to call someone, and what to send
Report the power cut itself to your network operator, not your energy supplier. In England, Scotland and Wales you can call 105 (Ofgem).
Call an engineer about the solar if, once the mains is back and it's daylight:
- the solar breaker trips again after you've reset it once
- an error code stays on the inverter screen
- the inverter screen is blank
- you can smell burning or see scorch marks (turn off the solar breaker first)
- the inverter screen and generation meter both show nothing after a few minutes, with the breaker on
Send us these on WhatsApp and we can usually tell you what you're looking at:
- a clear photo of the inverter screen, with any fault code
- a photo of your consumer unit showing the solar breaker
- a monitoring screenshot showing when it stopped, if the app is working
- roughly how old the system and the inverter are
- your postcode
Our solar servicing and repairs page explains what we check when we visit.
Key points
Switching off is normal. Grid-connected solar must disconnect in a power cut so it can't feed a network that engineers are working on.
It should restart by itself. G98 lets it reconnect once the mains has been steady for at least 20 seconds. Check in daylight, on the inverter screen or generation meter rather than the app.
Reset the breaker once. If it trips again, leave it off and call an engineer. Photograph any error code.
A battery isn't automatically a backup. It only keeps power on in a cut if it was designed and wired to do that.
Questions people also ask
Why would solar panels suddenly stop working?
The common causes are a power cut, a tripped solar breaker, an inverter fault or monitoring that has lost its wi-fi connection. Check the inverter screen and the breaker first, and photograph any error code before you call anyone.
Should I turn off my solar panels during a power cut?
You don't need to, because a grid-connected system disconnects itself when the mains fails. Leave the isolators alone and only turn off the solar breaker if you smell burning or see damage.
How long after a power cut do solar panels come back on?
Under the G98 rules the inverter waits until the mains has been steady for at least 20 seconds, so in daylight it should be running again within a few minutes. If it's still off after that, check the solar breaker in your consumer unit.
Will a solar battery work in a power cut?
Only if it was designed and wired to give backup, usually to a few essential circuits through a separate consumer unit. A standard battery switches off with the panels when the grid goes down.
We're based in Warrington and work on systems across the UK, whoever fitted them: WhatsApp us a photo of the error code or book a solar health check.
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