Lightning protection by structure · Complies to IEC 62305-3
Pitched and Tile Roof Lightning Protection
Pitched-roof lightning protection runs a ridge conductor with short air terminals and conductors down the roof slopes, held by holders made for tile, slate or sheet. It protects the ridge, hips, chimneys and eaves, which are the points most likely to be struck.
When it applies
- Tiled, slated and shingled pitched roofs
- Villas, resorts, heritage and institutional buildings
- Roofs with chimneys, dormers and finials above the ridge
- Roofs where appearance matters and fixings must not damage the covering
When it does not
- Continuous metal roofs thick enough to serve as the air termination
- Thatched roofs, which need conductors held clear of the thatch — design case by case
- Roofs under a taller neighbouring structure that already protects them (to be confirmed by rolling sphere)
How the system works
- InterceptAir termination is placed by rolling sphere, mesh or protective angle so that the strike lands on the system, not the structure.
- ConductSeveral straight, short down conductors share the current and keep voltages low.
- DisperseThe earth termination spreads the current into the ground with a low impulse impedance.
- EqualiseBonding and surge protection stop sparks between the system and what is inside the building.
Rolling sphere method
A sphere of the radius set by the protection level is rolled over the structure. Wherever it touches, a strike can land, so that point needs air termination. Everything it cannot touch is protected.
Design parameters
The values a consultant or contractor needs to fix before the system is drawn.
| Parameter | Typical value or rule | Reference |
|---|---|---|
| Protection level | LPL I–IV from the risk assessment; sets rolling-sphere radius 20 / 30 / 45 / 60 m | IEC 62305-2 · IEC 62305-3 |
| Ridge conductor | Along the full ridge and hips, with rods at ridge ends and at chimneys | IEC 62305-3 Cl. 5.2 |
| Mesh check | Roof slopes wider than the mesh size get additional conductors | IEC 62305-3 Table 2 |
| Conductor | Round 8 mm; copper on copper fittings, aluminium kept clear of copper | IEC 62561-2 |
| Holder type and spacing | Ridge, tile-hook and gutter holders matched to the covering; about every 1 m | IEC 62561-4 |
| Down conductors | From the eaves at each corner; average spacing by protection level | IEC 62305-3 Table 5 |
| Gutters and metal parts | Bonded to the LPS where they are within the separation distance | IEC 62305-3 Cl. 6 |
Solution pack: component BOQ
Each line opens the LPES product category. Part codes and final quantities are confirmed on your quote from the drawings.
| Component | Role in the system | Quantity rule |
|---|---|---|
| Conductor Holders | Ridge, tile and gutter holders | One per metre of ridge and slope conductor |
| LPS Conductors | Ridge, slope and down conductors | Ridge + hips + slopes to eaves + down runs |
| Clamp Connectors | Tee and cross joints, gutter and pipe connections | One per junction and per bonded metal part |
| Air Terminal Rods | Short rods at ridge ends, chimneys and finials | One per ridge end and per chimney |
From design to handover
- Fix the protection level and mark the ridge, hips and chimneys
- Fit ridge and tile holders without breaking the covering
- Run the ridge conductor, rods and slope conductors
- Bond gutters and metal parts and bring down conductors to test joints
- Inspect, test and record
Services for this solution
Industries that use it
What the standards require
Checked against the current editions held in the LPES standards library.
- IEC 62305-3:2024 Cl. 5.2
- The rolling sphere is the general method. The protection angle only supplements it for simple shapes, and the mesh method is for flat surfaces.
- IEC 62305-3:2024 Cl. 5.2
- An unprotected metal roof fixture needs its own protection if it stands more than 0.3 m above the roof, covers more than 1.0 m² or is longer than 2.0 m.
- IEC 62305-3:2024 Cl. 5.2.3
- Side flashes are negligible up to 60 m. Above that, protect the top 20% of the height.
- IEC 62305-3:2024 Cl. 5.3
- An exposed corner can share a down conductor if both neighbours are within half the Table 5 spacing.
- IEC 62305-3:2024 Cl. 5.3.5
- Natural down conductors are proven by a four-lead continuity test at about 10 A: 0.2 Ω or less from top to earth network.
- IEC 62305-3:2024 D.7.2
- Inspect visually every year and completely, with electrical tests, every three years; every year for public, sensitive and explosion-risk structures.
Regulation and standards cross-check
What Indian regulation and the wider standards add to this solution. Paraphrased; confirm against the current official text, amendments and state notifications before relying on a clause in a tender or inspection.
| Standard | Clause | What it requires |
|---|---|---|
| CEA Safety Regulations 2023 | Reg 38(3)(vi) | Lightning protection is required for multi-storeyed buildings above 15 m and for listed premises, which include hospitals, hotels, academic buildings, industrial installations and other public buildings. The regulation names no design standard, so IS/IEC 62305 applies through Reg 14. |
| CEA Safety Regulations 2023 | Reg 14(2), Reg 2(1)(zze) | Relevant standards, including the National Electrical Code and the National Building Code, shall be followed. Indian Standards come first, then IEC, IEEE and European Norms in that order. Where a standard and the regulations differ, the regulations prevail. |
| IS 3043:2026 | Clause 12.1.2.1, 13.7 | For lightning protection, a Type A earth electrode targets a resistance below 10 Ω, and the continuity of the lightning protection path is checked against 0.2 Ω. |
| IS 3043:2026 | Clause 6.3.1 | Separate or dedicated earth electrodes for individual equipment, neutrals, electronics or the lightning protection system shall not be followed. Electrodes are interconnected into one earthing system. |
| CEA Safety Regulations 2023 | Reg 43(v) | Every building shall have protective equipotential bonding that interconnects exposed and extraneous conductive parts. |
| IS 732:2019 | Clause 1, 4.5.3, 5.3.5 | The wiring code covers installations up to 1,000 V a.c. or 1,500 V d.c. Its surge clauses govern whether a surge protective device is needed and how it is selected, connected and coordinated. |
| CEA Safety Regulations 2023 | Reg 32(2), Reg 33(3) | Periodic inspection or self-certification is set by the Appropriate Government at intervals not longer than five years. Test instruments are calibrated by a Government-authorised or NABL-accredited laboratory. |
What we ask for before design starts
- Roof plan, elevations and sections with heights
- Use of the structure and its contents, for the risk assessment
- Roof and facade materials with sheet thickness
- Metal installations on the roof and services that enter the structure
- Soil resistivity and the existing earthing layout
- Single-line diagram for the surge protection design
Engineering depth: from the LPES Knowledge Hub
Topic studies written against the current standards. Open each part for the method, the mistakes to avoid and the checklist.
IEC 62305-3:2024 · LPES Knowledge Hub H-08
Protection angle method and protected volumes of rods and wires
The protection angle method positions an air-termination rod or line so that everything within a cone (for a rod) or a wedge (for a line) below it, at the defined protection angle, counts as protected. It is a simpler geometric shortcut than the rolling sphere method, but it is not universally valid: it only applies to simple-shaped parts of buildings, and only up to a height limit that shrinks as the class of LPS becomes more demanding. Above that limit, only the rolling sphere and mesh methods remain valid.
How it is applied
- Step 1: Confirm class of LPS and the reference height h of the rod or line air termination above its reference plane.
- Step 2: Check Figure 1 to confirm the protection angle method is still valid at that height for that class (i.e. h is not beyond the class-specific cut-off point marked in the figure); if it is beyond the cut-off, switch to the rolling sphere or mesh method instead.
- Step 3: Read the protection angle from Figure 1 for the confirmed class and height.
- Step 4: For a rod-type air termination, construct the protected volume as a cone (or, with two reference planes, two segments of cones per Figure 3 c)) rotating from the rod tip at the protection angle from vertical.
- Step 5: For a line-type air termination, construct the protected volume as a straight wedge along the conductor's length, and as a quarter-cone at each corner, per Figure 3 b).
- Step 6: Confirm the part of the structure being protected is fully contained within the constructed volume; where an elevated reference plane (such as a roof) has a physical edge, switch to the angle appropriate to the lower reference plane at that edge, not the angle valid on the elevated plane.
Common mistakes
- Applying the protection angle method above the height limit shown in Figure 1 for the applicable class, where only rolling sphere and mesh methods are valid.
- Using the protection angle for an elevated reference plane at the physical edge of that plane, instead of switching to the angle for the lower reference plane as required.
- Treating a rod's protected volume as a simple cone when two reference planes are actually involved (e.g. a rod on a stepped roof), missing the two-segment geometry of Figure 3 c).
- Forgetting that a line-type air termination's protected volume includes a quarter-cone at each corner, not just a uniform wedge along its length - corners need separate checking.
- Assuming the protection angle is constant regardless of height; it is a function of both class and height, per Figure 1, except that it does not change for h below 2 m.
Design checklist
- Confirm class of LPS and reference height h before selecting the protection angle method.
- Check Figure 1 to confirm the method is still valid at that height for that class.
- Read the correct protection angle from Figure 1 for the confirmed class and height.
- Construct the correct protected-volume geometry (cone for a rod, wedge plus corner quarter-cones for a line), including any two-reference-plane case.
- Switch to the lower reference plane's angle at the physical edge of an elevated reference plane.
- Fall back to rolling sphere or mesh methods wherever the protection angle method's height limit is exceeded.
Try the numbers
Protection level explorer
- Rolling-sphere radius
- 45 m
- Mesh size
- 15 × 15 m
- Down-conductor spacing
- 15 m
- Peak current covered
- 100 kA
- Coefficient ki
- 0.04
- Interception efficiency
- 90%
Values from IEC 62305-1 and IEC 62305-3. The level for your structure comes from the risk assessment.
What we find on audits
- Rooftop equipment standing outside the protected volume
- A single down conductor, or long loops around parapets
- Separation distance ignored, so current jumps to ducts and cable trays
- No test joints and no record of earth resistance
- External lightning protection installed with no surge protection on incoming lines
What you receive: the LPES Protection Passport
- As-built drawings of the installed system
- Risk assessment and design calculations
- Test results: earth resistance, continuity, SPD checks
- Component list with part codes and type-test references
- Inspection schedule for the protection level
Lightning to Load: one accountable partner
- Assess
- Design
- Specify
- Supply
- Implement
- Verify
- Assure
Standards basis
IEC 62305-1, -2 and -3:2024 (Ed. 3) · IS/IEC 62305 · IEC 62561 series · CEA Safety Regulations 2023 · IS 732:2019 · IEC 60364-6:2016 · IEC 61936-1:2021
Reviewed by LPES engineering, November 2026. Clause and table numbers follow IEC 62305:2024 (Edition 3) and IS 3043:2026.
Questions engineers ask
Do tiles have to be drilled?
No. Tile-hook and ridge holders clip under or over the tiles and are made for each covering type. Conductor Holders
How is a chimney protected?
With an air terminal rod fixed to it and connected to the ridge conductor. Air Terminal Rods
Which conductor material suits a tiled roof?
Copper or aluminium round conductor. Water running off copper must not reach aluminium or galvanised parts. LPS Conductors
Must gutters be connected?
Yes, where they are close to the conductors; they are bonded with a tested clamp. Clamp Connectors
Who decides the layout?
The LPS designer, from the risk assessment and the roof drawings. Lightning Protection System Design
Get this solution quoted for your site
Send the drawings or the basic dimensions. LPES returns the design parameters, the BOQ with part codes and the price in one offer.
