Surge protection devices for buildings
A strike does not have to hit your building to wreck what is inside it. A strike on a nearby cable or the ground sends a short, huge voltage spike along power, phone and data lines. Surge protection devices, or SPDs, divert that spike to earth before it reaches the equipment.
For a building with a lightning protection system, Type 1 surge protection at the intake is part of the design, not an extra. Published prices run from £400 to £700 for a commercial intake with protection at key equipment, to £2,500 to £5,000 for a full scheme across a building.
- At a commercial intake
- £400 to £700
- Full Type 1, 2 and 3 scheme
- £2,500 to £5,000
- Wiring rules
- BS 7671, section 443
- Lightning standard
- BS EN 62305-4
When surge protection is worth it
- The building has, or is getting, a lightning protection system on the roof.
- The supply comes in overhead, or the site is rural or exposed.
- Losing IT, fire alarms, CCTV, door entry, lifts or a server room would stop the day.
- It is a school, hospital, care home, church or public building where an outage affects many people.
- You have rooftop solar, EV chargers or plant with sensitive controls.
- You are having the electrics rewired or the distribution boards replaced anyway.
What surge protection costs
| Item | Typical figure |
|---|---|
| Type 2 device at a single-phase intake A small premises or house, fitted by an electrician | £120 to £180 |
| Combined Type 1 and 2 at the intake Overhead supply or a building with a lightning protection system | £250 to £400 |
| Commercial intake plus Type 3 at key equipment Typical small commercial building | £400 to £700 |
| Full Type 1, 2 and 3 scheme across a building Intake, sub-boards and sensitive equipment, designed together | £2,500 to £5,000 |
Where these figures come from
From published UK contractor price guides, autumn 2026 (a UK electrical contractor's guide dated April 2026 for the intake prices, a lightning protection specialist's guide dated October 2026 for full schemes), excluding VAT. Firms are not named.
Type 1, Type 2 and Type 3
Type 1, at the intake
Built to handle part of a direct lightning current. Fitted where the supply enters the building when there is a lightning protection system on the roof or an overhead supply, as part of bonding everything to the same earth.
Type 2, at distribution boards
Handles the induced surges from strikes nearby and switching on the network. The usual device for a main board or sub-board, and often combined with Type 1 in a single unit at the intake.
Type 3, at the equipment
Fine protection close to sensitive kit such as servers, alarm panels, organ blowers or lab equipment. It only works with Type 1 or 2 upstream.
What the rules say
BS 7671, the wiring regulations, expects protection against transient overvoltages in most installations, and in particular where an overvoltage could cause serious injury, interrupt public services, damage cultural heritage or stop commercial or industrial activity. BS EN 62305-4 covers protection of electrical and electronic systems inside a building with a lightning protection system.
What a good surge protection design covers
A device in the wrong place, or with long leads, protects very little. These are the points to check.
Every service, not just power
Phone, data, CCTV and alarm lines entering the building need their own protection or a spike simply comes in another way.
Coordinated types
Type 1, 2 and 3 chosen to work together from intake to equipment, from the same family of tests.
Short connecting leads
Long leads add voltage during a surge. The installer should keep them short and say how.
Status you can see
Devices with a visible indicator or remote alarm, checked at each lightning protection test.
How surge protection gets fitted
Survey
The supply, boards, incoming services and critical equipment are noted, with any lightning protection on the building.
Design
Types and locations chosen so they coordinate, with any risk assessment the wiring rules call for.
Install
Devices fitted at the intake, boards and equipment, usually with a short planned shutdown.
Certify
Recorded on the electrical certificate, and added to the annual lightning protection test checklist.
Questions people ask
What is a surge protection device?
A device fitted in or near a distribution board that diverts a sudden high voltage to earth before it reaches wiring and equipment. Surges come from lightning nearby and from switching on the electricity network.
Is surge protection required by BS 7671?
The current wiring regulations expect protection against transient overvoltages in most new and altered installations, and require it where the consequences of an overvoltage would be serious, for example to public services or commercial activity. Your electrician records the decision on the certificate.
Do I need surge protection if I have a lightning conductor?
Yes. A lightning protection system protects the structure; a strike on it raises the building's earth and pushes current onto incoming cables. Type 1 surge protection at the intake is part of a BS EN 62305 design.
How much does surge protection cost to fit?
Published guides put a Type 2 device at a single-phase intake at £120 to £180, a combined Type 1 and 2 at £250 to £400, a commercial intake with Type 3 at key equipment at £400 to £700, and a full scheme at £2,500 to £5,000.
Do surge protectors wear out?
Yes, each surge uses some of the device up. Most have an indicator that changes colour at end of life; check it at the annual lightning protection test and after storms.
Get surge protection designed and priced
Three quick screens: the postcode of the building, the work, then your contact details. Most people finish in about two minutes.
We are an introduction service, not a lightning protection contractor. We tell you which specialist covers your building before anything is shared, and no one calls you unless you agree.
Thanks, your enquiry is in.
- We aim to tell you within one working day which specialist we suggest for your building.
- Nothing is sent to them until you give the go-ahead.
- They check the building and its system and send you a written price. We will not send you marketing.