Inverters & components
Do solar panels work in a power cut?
It surprises almost everyone: when the grid goes down, a standard solar installation goes down with it — even in bright sunshine. That's not a flaw; it's a deliberate safety requirement.This guide explains why, and what genuine backup power actually requires.
Written and edited by Christopher Panteli
Christopher is the founder and editor of MyPlugInSolar. He oversees the site’s research standards, data tools and editorial process. He is not an electrician or solar installer, and specialist technical claims are sourced from official documentation or reviewed by appropriately qualified professionals.
Why your panels go dark with the grid
Every grid-tie inverter continuously monitors the mains. The moment the grid disappears, the inverter must disconnect and stop generating — a protection called anti-islanding. The reason is stark: engineers repairing a fault work on cables they believe are dead. A house quietly feeding solar power back into a 'dead' network could injure or kill them. So the rule is absolute for standard systems: no grid, no solar — regardless of sunshine.
What real backup requires
Backup is possible, but it's a system feature, not a panel feature. A battery system with a dedicated backup function (often called EPS — emergency power supply) can disconnect the house (or a protected circuit) from the grid entirely and run it as an isolated island, safely, because nothing leaks back into the network. That requires the right inverter, a changeover arrangement and professional installation — it is not something to improvise.
Safety and compliance
The simpler alternatives
If outages are rare where you live (for most of the UK they are), a portable power station covers the essentials — router, phones, a lamp, medical kit — without touching your wiring, and portable panels can recharge it in prolonged outages. Worth knowing: plug-in solar systems behave like any grid-tied system here — they also shut down in a power cut — quite apart from being not yet legal to use in the UK. To report or check a power cut, call 105 — it routes to your network operator.
Frequently asked questions
- Why don't solar panels work when the power goes out?
- Because grid-tied inverters are required to shut down when the grid fails (anti-islanding), so they can't energise cables that network engineers believe are dead. Only systems with a dedicated, professionally installed backup function can power a home during an outage.
- How can I use solar power during a power cut in the UK?
- Either a battery storage system with a backup/EPS function installed by a qualified electrician, or — far simpler — a portable power station charged in advance (and rechargeable by portable solar panels), which powers essentials without touching your home's wiring.
Sources
- 1. Engineering Recommendations G98/G99 (connecting generation) — Energy Networks Association
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