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Field Testing & Twin SaaS
🇬🇧 Full UI + PDF + National Standard Mapping: UI + PDF in English. Normative references follow international IEC 60364, BS 7671:2018+A2:2022, IEEE, and NFPA 70E/70B.
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#15Lightning Protection System (LPS) & SPD Engineering Audit

Project Framework (report reference): IEC 60364-4-41Applicable Standard: IEC 62305-1/2/3/4
Module Field Guides, Standard Selection & Tutorials (3)Browse All 93+ Guides →
1 · Field Measurement ProcedureHow to Measure & Test Lightning Protection (LPS) on Site: Step-by-Step Field Procedure (IEC 62305-1/2/3/4)2 · Standards & Limit TablesWhich Standard Applies to Lightning Protection (LPS)? Acceptance Limits, Annex Tables & Regional Equivalents (IEC 62305-1/2/3/4)3 · OhmCert Tutorial & Case StudyHow to Complete a Lightning Protection (LPS) Certificate in OhmCert: Worked Case Study & Troubleshooting

Multi-Asset / Multi-Point Equipment Schedule

Inspect multiple transformers, panels, rooms, motors, or RCDs in this module without overwriting previous assets. Each item receives a permanent QR Sticker UID preserved across annual audits.

Sticker UID: OC-LPS0-75C8
Plant & SLD (Auto-SLD)

Standard Limits, Equations & Space Presets

Comprehensive IEC 62305-1/2/3/4 Lightning Protection engineering engine: collection area Ad, annual strike risk ND, rolling sphere & mast protection radius rp, down-conductor count, separation distance s = ki·kc·l/km, minimum electrode length l1, and SPD effective protection level Up/f.

One-Click Normative Presets (Auto-fills Target Limits)
Governing Equations & Physical Constants
Ad & ND

Ad = L·W + 6H(L+W) + 9·pi·H^2 | ND = Ng x Ad x 10^-6

Equivalent collection area (m2) of isolated structure and expected direct lightning flashes per year (IEC 62305-2 Annex A).

rp (Mast Cone)

rp = sqrt(h x (2r - h))

Protected radius on horizontal plane for air-termination mast height h and rolling sphere radius r (IEC 62305-3 §5.2.2).

s (Separation)

s = (ki x kc / km) x l

Minimum separation distance (m) to prevent dangerous sparking between LPS and internal metallic installations (IEC 62305-3 §6.3).

IEC 62305-3 Table 2 & Table 4: LPS Class Geometry & Separation Coefficients

IEC 62305-3 §5.2 & §6.3
LPS Class (LPL)Peak Current I_max / I_minRolling Sphere Radius rMax Mesh SizeDown-Conductor SpacingCoefficient ki
Class I (LPL I)200 kA / 3 kAr = 20 m5 x 5 m10 mki = 0.08
Class II (LPL II)150 kA / 5 kAr = 30 m10 x 10 m10 mki = 0.06
Class III (LPL III)100 kA / 10 kAr = 45 m15 x 15 m15 mki = 0.04
Class IV (LPL IV)100 kA / 16 kAr = 60 m20 x 20 m20 mki = 0.04

Material factor km: Air = 1.0, Concrete / Brick / Wood = 0.5. Partitioning factor kc: 1 conductor = 1.0, 2 conductors = 0.66, 3+ conductors / mesh / ring earth = 0.44.

Measured Inputs

IEC 62305 Collection Area, Rolling Sphere, Separation Distance & SPD Evaluation

Parametric IEC 62305-2/3/4 calculator: evaluates structure Equivalent Collection Area Ad & annual direct strike frequency ND, Rolling Sphere & Air-Termination Mast protection cone radius rp, perimeter down-conductor count, Separation Distance s = (ki x kc / km) x l, minimum earth electrode length l1 from soil resistivity rho, and SPD effective protection level Up/f.

Pending / Not tested — results stay neutral until valid measured values are entered.

  • Protection Level Class II Normative Geometry

    Rolling sphere r = 30 m | Mesh 10 x 10 m | Max down spacing 10 m

    IEC 62305-3 Table 2 & Table 4 geometric criteria for the selected Lightning Protection Level (LPL).

    Pending

  • Collection Area Ad & Annual Strike Frequency ND (IEC 62305-2)

    -

    Calculated per IEC 62305-2 Annex A.2 (Ad = L·W + 6H(L+W) + 9·pi·H^2) at Ng = 2.5 flashes/km2/yr.

    Pending

  • Air-Termination Mast Protected Cone Radius rp (IEC 62305-3 §5.2.2)

    -

    Rolling sphere protected radius rp = sqrt(h x (2r - h)) around air-termination rod.

    Pending

  • Perimeter Down-Conductor Count Adequacy

    -

    Not tested - enter the measured value. Acceptance: At least 2 down conductors and <= 10 m average spacing around perimeter for Class II [IEC 62305-3 §5.3.3 & Table 4]

    Pending

  • Separation Distance s = (ki x kc / km) x l

    -

    Not tested - enter the measured value. Acceptance: Actual separation s_actual >= calculated s to prevent side-flashing, otherwise bond directly [IEC 62305-3 §6.3 / Table 4]

    Pending

  • Earth Termination Resistance & Min Electrode Length l1

    - Ohm

    Not tested - enter the measured value. Acceptance: RA <= 10 Ohm combined earth termination (measured isolated from protective earth) and electrode length >= l1 [IEC 62305-3 §5.4.1 & Figure 2]

    Pending

  • Down Conductor & Test Joint Continuity

    - Ohm

    Not tested - enter the measured value. Acceptance: End-to-end metallic continuity from air-termination through test joint to earth <= 0.20 Ohm [IEC 62305-3 Annex E.5]

    Pending

  • SPD Effective Protection Level Up/f = Up + Delta_U(lead)

    -

    Not tested - enter the measured value. Acceptance: Effective protection voltage Up/f <= 2.5 kV (Category II Uw) and total SPD lead length <= 0.50 m [IEC 62305-4 / IEC 60364-5-53 §534.4.4 & §534.4.8]

    Pending

Verification Checklist (0 / 20)

Pending

  • 1Lightning Risk Assessment (R1, R2, R3, R4 vs tolerable risk RT = 10^-5) documented per IEC 62305-2

  • 2Air-termination system (rods, catenary wires, or meshed conductor grid) covers all roof corners and parapets [IEC 62305-3 §5.2]

  • 3Rooftop HVAC units, chillers, PV frames, vents and antennas positioned inside Rolling Sphere / lp cone or protected by isolated air terminals

  • 4Conductor cross-sections comply with IEC 62305-3 Table 6 ( >= 50 mm2 Cu/Al or >= 50 mm2 hot-dip galvanized steel, min 8 mm dia rod)

  • 5Down conductors routed straight and vertically with no sharp bends (radius R >= 20 cm) or re-entrant loops

  • 6Down-conductor perimeter spacing complies with LPL Class (10 m Class I/II, 15 m Class III, 20 m Class IV) [IEC 62305-3 Table 4]

  • 7Disconnecting test joint fitted on every down conductor at 1.5 - 2.0 m above ground and labelled

  • 8Calculated separation distance s maintained between LPS and internal metal pipes/cable trays, or equipotential bonding installed

  • 9Type A (vertical/radial rods >= l1) or Type B (ring conductor >= 80% in soil contact at >= 0.5 m depth) earth termination verified

  • 10Foundation earth electrode (Ufer ground) interconnected to main earthing busbar via stainless steel (V4A / AISI 316) exit risers

  • 11Earth inspection pits accessible, drained, labelled, and clamp connections coated with anti-corrosion petrolatum tape

  • 12Bimetallic connectors (Cu-Al / Cu-Fe) installed at all dissimilar metal transitions to prevent galvanic corrosion

  • 13Lightning Equipotential Bonding (LEB) at LPZ 0A/1 boundary verified for water, gas, fire sprinkler, and structural steel

  • 14Type 1 (10/350 us impulse, Iimp >= 12.5 kA/pole) SPD installed at main LV switchboard incomer

  • 15Coordinated Type 2 (8/20 us) SPDs fitted at sub-distribution boards where cable distance from Type 1 exceeds 10 m

  • 16SPD connecting leads (Line + PE / V-wiring) kept straight and <= 0.50 m total length [IEC 60364-5-53 §534.4.8]

  • 17SPD status indicators healthy (green), remote alarm dry contact wired, and dedicated backup fuse/MCB coordinated

  • 18Data, telecom, coax and rooftop PV DC strings protected with Type 1/2 surge arresters at building entry

  • 194-wire micro-ohmmeter continuity (<= 0.2 Ohm) and isolated earth resistance measurements logged per down conductor

  • 20As-built LPS layout drawing, rolling sphere diagram, and periodic inspection schedule (1-2 yr Class I/II, 2-4 yr Class III/IV) signed off

General Notes

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Free plan: 5 of 5 inspections / calculations left this month.