Sector applications · Complies to VG 96927
Temporary, Mobile and Defence Protection
Temporary and mobile installations — field camps, event structures, mobile towers and deployable shelters — need protection that can be set up and removed quickly. It uses mobile masts on stands, portable earthing, pre-packed kits and storm warning.
When it applies
- Defence and disaster-relief field deployments
- Mobile communication and radar units
- Events, exhibitions and temporary structures
- Construction sites and work camps
When it does not
- Permanent buildings, which follow the structure solutions
- Sites where no earth connection of any kind can be made
- Use as a substitute for evacuation when a storm warning is given
How the system works
- AssessA lightning risk assessment and the sector's own standard set the protection level.
- Earth and bondEvery structure, frame and cabinet is joined to one earthing system.
- Protect the linesCoordinated surge protective devices are fitted on power, DC, RF and data lines.
- Monitor and maintainCounters and status contacts show what happened; inspection keeps the system in service.
Coordinated surge protection
Each device takes its share. The Class I device diverts lightning current at the service entry; Class II and III devices bring the remaining voltage below what the equipment can withstand.
Design parameters
The values a consultant or contractor needs to fix before the system is drawn.
| Parameter | Typical value or rule | Reference |
|---|---|---|
| Air termination | Free-standing mobile masts placing the shelter or vehicle inside the protected volume | IEC 62305-3 |
| Mast support | Tripods or stands with ballast or guys for the site wind speed | IEC 62305-3 Annex D |
| Earthing | Driven rods or surface radials, at least two per mast | IEC 62305-3 Cl. 5.4 |
| Portable earthing | Rated sets for generators, vehicles and temporary distribution | IEC 61230 |
| Storm warning | Thunderstorm warning with defined actions | IEC 62793 |
| Set-up time | Kit packed and labelled for assembly without special tools | LPES kit specification |
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 |
|---|---|---|
| Portable & Temporary Earthing | Portable earthing sets for generators, vehicles and distribution | One set per generator or vehicle |
| Tripods & Mast Stands | Stands and ballast for mobile masts | One per mast |
| Lightning Detection & Warning | Portable thunderstorm warning | One per site |
| Lightning Protection Kits | Pre-packed lightning protection kit | One kit per shelter or vehicle |
From design to handover
- Define what must be protected and how long it stays
- Choose mast height and number from the protected volume
- Set up masts on stands and connect to driven rods or radials
- Earth generators and vehicles and set up storm warning
- Brief the team; inspect after every storm and before each move
Services for this solution
Industries that use it
What the standards require
Checked against the current editions held in the LPES standards library.
- IEC 62305-2:2024
- Risk to life and physical damage is compared with a tolerable risk of 10⁻⁵ per year; failure of internal systems is judged separately as a frequency.
- IEC 62305-4:2024
- A coordinated SPD system protects against conducted surges only. Radiated fields need shielding and cable routing.
- IEC 62305-4:2024 Cl. 7
- Where an external LPS exists, a Class I (Type 1) SPD is required at the service entry.
- IEC 62305-4:2024
- Earthing conductor to the SPD: 16 mm² copper for Class I, 6 mm² for Class II and 1.5 mm² for Class III.
- CEA Safety Regulations 2023, Reg. 38(3)
- Lightning protection is addressed for multi-storeyed buildings above 15 m and listed public premises such as airports, hospitals and hotels.
- IEEE 80-2013
- A substation grid is judged by touch and step voltage against the tolerable limits, not by its resistance alone.
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 |
|---|---|---|
| IS 3043:2026 · NEC 2023 | Clause 11, NEC Part 3 Section 5 | Construction sites follow the National Electrical Code section for temporary installations, with residual current protection and verified earthing on every temporary supply. |
| CEA Safety Regulations 2023 | Reg 44 | Supply is controlled by a residual current device rated per the relevant standards. Domestic installations use a device with a residual operating current not above 30 mA. |
| IEC 60364-6:2016 | 6.5.2 | Periodic verification is typically every few years, for example four. Shorter intervals suit construction sites, communal facilities, sites with both high and low voltage, and workplaces where degradation raises shock, fire or explosion risk. |
| IEC 60364-6:2016 | 6.4.3.7 | In a TT system the earth electrode resistance is measured and the residual current device is tested. In a TN system the loop impedance is measured, or protective conductor continuity is proved where calculations exist. |
| IEC 60364-6:2016 · IS 732:2019 | 6.4.3.7.3, Annex D | A measured earth-fault loop impedance is accepted when it is not more than two thirds of U0 ÷ Ia, where Ia is the current that operates the device in the required time. The margin covers conductor heating under fault. |
| CEA Safety Regulations 2023 | Reg 43(v) | Every building shall have protective equipotential bonding that interconnects exposed and extraneous conductive parts. |
| 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. |
What we ask for before design starts
- Single-line diagram with sources, operating modes and earthing arrangement
- Equipment list with impulse withstand levels
- Cable routes and every point where services enter
- Fault levels and protection clearing times
- Existing earthing and lightning protection records
- Site layout with fences, pipes, rails and neighbouring installations
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 62305-2:2024 · LPES Knowledge Hub H-58
Thunderstorm warning systems ,IEC 62793, as temporary preventive measures
A thunderstorm warning system (TWS), built and operated to IEC 62793, is a monitoring and alerting system that detects an approaching or ongoing lightning-related event over a defined surrounding area and issues a warning in time for people to take preventive action. IEC 62305-2:2024 recognises a TWS as a genuine, quantified protection measure for the first time in this edition: where a TWS is in place and its warning reliably triggers evacuation or disconnection, the standard lets the risk assessor apply a probability factor, PTWS, that reduces several of the risk components tied to human presence and to failures triggered by flashes to or near a connected line. A TWS is explicitly a temporary, procedural measure — it reduces exposure for the duration of the warning, it does not reduce the physical hazard itself, and its credit is capped by how reliable the warning is and how completely people actually act on it.
How it is applied
- confirm eligibility: establish that the installed or proposed system is a TWS compliant with IEC 62793, and that it serves the specific structure, open area or line section being assessed as its "surrounding area."
- obtain FTWR and PODx: these figures must come from the TWS manufacturer's product data sheet or the service provider; the risk assessor does not derive them independently. If neither figure is declared, PTWS = 1 must be assumed — the TWS earns no credit in the calculation even if physically installed.
- confirm the operating procedure: for every component except PZ, the credit depends on the warning reliably producing prompt and complete evacuation of the exposed area within the available lead time. For PZ specifically, the credit depends on immediate and complete disconnection of the external distribution lines.
- If the facility cannot demonstrate that this procedure actually happens (trained personnel, a defined evacuation or disconnection drill, enough lead time to execute it), PTWS = 1 must be assumed regardless of the detector's own reliability figures.
- compute PTWS = max(FTWR, 1 − PODx) and insert it into whichever of the six equations in Section 7 apply to the risk components being assessed for that structure, zone, or line section.
- apply the B.3 simplification where relevant: if a TWS is in use for the PAD component specifically, the standard allows Pam to be ignored in that equation (NOTE 2 under B.3) — the open-area hazard is being managed by evacuation rather than by the touch/step measures that Pam otherwise represents.
- never apply PTWS to a risk component whose equation does not print the term (PB, PC, PM per Section 4) — a TWS does not get credited there even if one is installed, because those equations govern fire/explosion and internal-system failure mechanisms that a human evacuation or line disconnection does not interrupt in the way the standard models them.
- A TWS credit is always temporary and procedural: it reduces the probability a person is caught in the dangerous place, or that an unprotected line stays connected, during the warned interval — it never substitutes for LPS class selection, coordinated SPD design, or bonding.
Common mistakes
- Assuming any installed lightning-detection product automatically earns PTWS credit — it does not, unless it is IEC 62793-compliant and its FTWR/PODx are actually declared by the manufacturer or service provider.
- Applying PTWS to risk components whose equations do not contain the term (PB, PC, PM) — the standard's own equations settle this; there is no PTWS factor to insert there.
- Treating the TWS credit as permanent risk reduction rather than as a reduction tied to the specific warned interval and the procedure that follows it — if the evacuation or disconnection procedure lapses, the credit is not real on the day it matters.
- Forgetting the PZ-specific condition: for internal-system failure from a flash near a line (B.10), the credit requires immediate and complete disconnection of the external distribution lines, not merely personnel evacuation — a facility that evacuates people but leaves lines connected does not qualify for TWS credit on PZ.
- Double-counting Pam and PTWS together in the PAD equation when NOTE 2 under B.3 specifically says Pam can be ignored once a TWS is in use for that component.
- Quoting a vendor's generic reliability marketing figure as FTWR/PODx without confirming it is declared for the specific site's lead-time requirement and surrounding area.
Design checklist
- Confirm the detection/alerting system is IEC 62793-compliant before treating it as a TWS for risk-assessment purposes.
- Obtain the manufacturer's or service provider's declared FTWR and PODx (with its associated lead time in minutes) in writing.
- Confirm, for each candidate risk component, whether its governing equation actually contains a PTWS term (PAT, PAD, PU, PV, PW, PZ, PP) — do not apply it elsewhere.
- Confirm and document the operating procedure that converts a TWS warning into action: evacuation for PAT/PAD/PU/PV/PW; immediate, complete disconnection of external distribution lines for PZ.
- Confirm the declared lead time is actually sufficient, in practice, for that procedure to complete — not just nominally sufficient on paper.
- If any of the above cannot be confirmed, set PTWS = 1 in the calculation rather than using the vendor's reliability figures.
- Where a TWS is credited for PAD, apply the NOTE 2 simplification (Pam ignored) rather than multiplying both factors.
- Record the TWS's surrounding area (SA) against the specific zone or line section it is being credited for — a TWS covering one part of a site does not automatically cover every risk zone on that site.
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.
Maximum earth-fault loop impedance
- Trip current Ia
- –
- Design limit for Zs
- –
- Without the 2/3 margin
- –
Zs ≤ (2 ÷ 3) × U0 ÷ Ia for miniature circuit breakers to IS/IEC 60898, instantaneous trip. Every circuit and every source is checked, as CEA Reg 43(xii) requires.
What we find on audits
- Equipment earths and lightning earths kept separate
- Surge protective devices chosen without coordination or the right voltage rating
- Long connecting leads that add kilovolts to the protection level
- Data and signal lines left unprotected while power lines are protected
- No inspection after a strike, so failed devices stay in service
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 62305-2, -3 and -4:2024 (Ed. 3) · IEC 61643 series · IEEE 80-2013 · IEC 61936-1:2021 · IS 3043:2026 · 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
Can a tent or shelter be protected from lightning?
Yes, by mobile masts that place it inside a protected volume, connected to temporary earth electrodes. Lightning Protection Kits
How is a mast kept upright without foundations?
On a tripod or stand with ballast or guys sized for the wind speed. Tripods & Mast Stands
How do I earth a mobile generator?
With a portable earthing set and a driven rod, connected before the generator is started. Portable & Temporary Earthing
What does a storm warning add?
Time to stop outdoor activity and move people to shelter before the first strike. Lightning Detection & Warning
Can the team be trained to deploy it?
Yes. LPES runs awareness and deployment sessions for site teams. Awareness Session for Owners, Consultants & EPCs
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.
