Lightning protection testing and inspection
A lightning protection system can look perfect from the ground and still fail. Joints corrode, clips let go, earth rods dry out, and tape goes missing to scrap thieves. The annual test is the only way to know the route to earth still works.
A tester inspects every visible part, checks continuity from roof to ground and measures the resistance of each earth. Published prices run from about £200 for a simple building to £450 to £800 for a school, and the Department for Education's estate management guidance tells schools to test at least once a year.
- Small commercial building
- £300 to £500
- School or large site
- £450 to £800
- Usual interval in the UK
- Every 11 to 12 months
- Earth target
- 10 ohms or less
When you need a test
- It is 11 to 12 months since the last test, or you cannot find the last certificate.
- The building has been re-roofed, extended or had plant, aerials or solar panels added.
- You have had a strike or a near miss, or storm damage nearby.
- Tape, clips or test clamps look missing, loose or green with corrosion.
- Your insurer, a diocese, a landlord or an auditor asks for a current certificate.
- You have taken on a building and inherited a system with no records.
What a test costs
| Item | Typical figure |
|---|---|
| House or small single building 1 to 4 down conductors, two to four hours on site | £200 to £350 |
| Small commercial, office or church Simple system, part of a day | £300 to £500 |
| School, large commercial or multi-storey Around half a day | £450 to £800 |
| Industrial site or several blocks A full day or more | £800 to £1,500+ |
| Inspection after a suspected strike Separate visit, sized by system | £350 to £600 |
| Three-year testing contract, public estate Public body, Shrewsbury (West Midlands), February 2025, value as published | £90,729 |
Where these figures come from
Test prices are typical ranges from published UK contractor price guides, autumn 2026, excluding VAT, read October and November 2026. Firms are not named. Contract values are copied from Contracts Finder or Find a Tender notices, ex VAT where stated, and show the size of real jobs rather than a rate for yours.
What the test actually checks
Visual inspection
Every air terminal, roof conductor, down conductor, joint, clip, test clamp and earth pit that can be seen, checked for damage, corrosion, loose fixings, missing sections and anything new on the roof that sits outside the protection.
A good tester walks the roof where it is safe to do so, or uses binoculars, a drone or a platform where it is not, and says which.
Continuity
A low-resistance reading between the air termination and each test clamp, which proves the metal path from roof to ground is unbroken. A high reading points to a corroded joint or a broken section somewhere above.
Earth resistance
Each earth electrode measured on its own with its test clamp opened, then the whole system measured together. BS EN 62305 recommends an overall reading of 10 ohms or less, noted by Historic England. Readings are compared with last year's, because a steady rise matters as much as a single high figure.
Some testers vary the month, testing at 11 or 13 month intervals, so readings are taken in different seasons; dry summer ground reads higher than wet winter ground.
The report
A certificate with each reading, a pass, fail or conditional pass, a list of defects in priority order and the date the next test is due. It should say whether the system meets the current standard or an older one, because many older systems pass their readings but have too few down conductors for BS EN 62305.
What a good test includes
Prices vary because testers do different amounts of work. Compare like with like.
Every earth tested separately
Not only one overall reading. A single figure can hide one good earth carrying several dead ones.
Readings set against last year
The report should show the trend, not just today, and flag any electrode that has risen sharply.
An up-to-date drawing
A sketch of the system marking each test point. If you have none, ask for one; it makes every later test quicker and cheaper.
Photos of defects
So you, a governor, a PCC or a finance team can see what the repair quote is for.
Surge devices checked
Most surge protection devices show a status window. A tester should note any that have tripped or reached end of life.
How the test visit runs
Book and brief
Share the last certificate and drawing if you have them, and arrange access to the roof, pits and plant rooms.
Inspect
Visual check of the whole system from roof to ground, noting damage, corrosion and anything new on the building.
Measure
Continuity and earth resistance readings at every test clamp, then the system as a whole.
Report and repair
A certificate and defect list, usually within a few working days, with a separate quote for any repairs.
Questions people ask
How often should lightning protection be tested?
In the UK the usual answer is every year. BS EN 62305-3 sets maximum gaps by class, as short as one year for a full inspection where a building has sensitive systems or holds many people, and the Department for Education says schools should inspect and test at least annually. See the interval table on our BS EN 62305 page.
How much does lightning protection testing cost?
Published UK prices run from about £200 to £350 for a house or small building, £300 to £500 for a small commercial building or church, and £450 to £800 for a school. Industrial sites start around £800. Repairs are quoted separately.
What earth resistance reading is a pass?
BS EN 62305 recommends an overall earth resistance of 10 ohms or less for the system. Individual electrodes are judged together with the overall figure and the trend over previous years.
What does a conditional pass mean?
The readings are acceptable but something needs attention, often that the system predates BS EN 62305 and lacks down conductors or earths the current standard expects. It is not urgent like a fail, but it should be planned.
Can the test be done without going on the roof?
The electrical tests are done at ground level at the test clamps. The visual check of the roof needs safe access or a good view; ask how the tester plans to inspect it and whether it is included.
Who can test lightning protection?
A competent specialist with the right earth tester and training. Insurers and dioceses often look for membership of ATLAS, the trade body for lightning protection and steeplejack firms.
Book a lightning protection test
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.