Solar Panels and Lightning: Surge Protection Guide UK

Solar panels and lightning are a common worry on UK roofs, but the real risk is not what most people expect. Solar panels do not appear to make a lightning strike more likely, yet a storm nearby can still send a damaging surge through the cabling into your inverter. That is why surge protection devices (SPDs) matter, and why it is worth knowing what your installer fitted before the next storm arrives.

This guide explains how UK lightning really works, what the wiring rules say about surge protection on solar PV, whether insurance and inverter warranties are likely to pay out, and what to do after a storm.

Do solar panels attract lightning in the UK?

No evidence says they do. One installer knowledge-base article makes the point plainly: panels do not increase the likelihood of a strike, and homes with panels are not hit more often. That is a commercial source rather than independent research, and a few surge-protection vendors argue the opposite, so treat the claim as the prevailing view rather than settled science.

The UK is not a lightning hotspot. The Met Office says the country sees roughly 200,000 to 300,000 lightning strikes a year, while TORRO notes that only about a quarter of lightning is cloud-to-ground. Spread across the whole country, a direct hit on any one house is rare. We could not find an authoritative per-household probability, so we are not going to invent one.

The real risk: induced and grid-borne surges

A strike does not need to hit your roof to cause damage. Lightning landing on a nearby tree, building or overhead line can induce a voltage spike in metal cabling or travel along the grid supply. Solar systems have long DC cable runs across the roof and an inverter that is both connected to the grid and full of sensitive electronics, so they have more ways for a surge to get in.

Research from the University of Strathclyde has argued that DC cabling will seldom withstand an induced lightning surge current, and questions installer assurances that an inverter's built-in protection is enough on its own. Trade guidance describes Type 2 SPDs as the device that protects the inverter and AC side from surges induced by nearby strikes and from grid-borne surges. Only an external lightning protection system can protect against a direct hit, and that is not a standard domestic fit.

What the wiring rules say about surge protection

UK electrical installations follow BS 7671, the IET Wiring Regulations. According to trade-press analysis of Amendment 2 (published 2022), overvoltage protection is required where a surge could seriously injure, disable a safety service, or cause significant financial or data loss, and Amendment 2 effectively makes SPDs the expected default for other cases too, with the owner able to decline and accept the risk. The old risk-assessment calculation route is gone, and the special exemption for single dwellings was removed.

For solar PV specifically, the same analysis says that where Section 443 requires overvoltage protection, it must also be applied on the DC side of the array. It adds that:

• an inverter's built-in SPD only counts if the manufacturer specifies it for the DC side;
• varistors inside an inverter do not count as an SPD;
• DC-side SPDs should comply with BS EN 61643-31;
• a Type 1 DC SPD is needed where the array is inside a lightning-protected volume and the separation distance is not met.

Caveat: these points come from trade-press paraphrase of the regulations, not the BS 7671 text itself. Ask your MCS installer to confirm in writing which SPDs they fitted and to which standard. Our solar panel cost guide covers what a typical installation quote should include.

How much does surge protection cost?

Costs are not well documented from authoritative sources. Electrician quotes we saw suggest roughly £80 to £150 for a Type 2 SPD, higher if retrofitted into an existing consumer unit. Treat that as an indicative range only and ask your installer to itemise it. On a system costing thousands of pounds, it is a small line item compared with replacing an inverter, which we cover in replacing a solar inverter.

Will home insurance cover lightning damage to solar panels?

Often, but check your wording. Broker guidance says panels should typically be covered for fire, storm damage, theft and vandalism once your insurer knows about them, but may not be covered for accidental damage. Some providers reportedly exclude storm damage to solar panels from standard buildings cover, according to Fairer Finance as quoted in the press. We could not verify whether insurers treat a grid-borne surge as lightning, or whether batteries are covered, so ask directly.

Our guide to solar panels and home insurance explains what to tell your insurer and the gaps that catch homeowners out.

Does the inverter warranty cover lightning?

Do not assume it does. Many inverter warranties list lightning and overvoltage under force majeure exclusions. SMA's factory warranty document, for example, excludes force majeure including lightning, overvoltage, storm and fire. That document is an older issue hosted by a UK reseller, so check the current UK terms for your brand. Third-party copies of Fronius terms show similar wording, with a note that a correctly installed overvoltage protection device can matter. Huawei and Sungrow terms were not verified.

The practical lesson: surge protection is what stands between a storm and a possibly excluded repair bill. See also solar panels and your roof warranty and our best solar inverter guide.

What to do during and after a storm

The Met Office advice during thunder and lightning is to unplug non-essential appliances if you are not using a surge protector, because lightning can cause power surges. Stay away from downed power lines and broken cables.

We found no UK body publishing solar-specific post-storm steps, so the following is common-sense guidance rather than official advice:

1. Do not touch suspect equipment. Panels stay live in daylight, so do not open or handle damaged cabling.
2. Look at the inverter. A red or amber fault light, or no display at all, needs a professional.
3. Check generation. A sudden drop in your app after a storm is worth investigating.
4. Photograph everything before any repair, in case you claim.
5. Call your MCS installer, then your insurer, and check your warranty terms.

Routine checks help too; see our solar panel maintenance guide.

Questions to ask your installer

• Is there an SPD on the AC side, the DC side, or both, and which type?
• Does the inverter's built-in protection count as a DC-side SPD per the manufacturer?
• Where is the SPD relative to the inverter, and does it have a status indicator?
• What does the current UK warranty say about lightning and overvoltage?

If your system has a battery, the same questions apply to the battery inverter, as covered in our hybrid inverter buyer guide.