Sector applications · Complies to ITU-T K.56 · IEC 60728-11
Telecom Tower Earthing and Protection
A telecom tower is the tallest object on its site and is struck often. Protection gives the lightning current a direct path down the tower to a ring earth, bonds the tower, shelter and feeders to one earth bar, and fits surge protection on power, RF and data lines.
When it applies
- Ground-based lattice towers and monopoles
- Rooftop towers and poles
- Radio base stations, microwave and broadcast sites
- Small cells and street-level sites, in reduced form
When it does not
- Indoor-only network rooms, which follow the critical facility solution
- Sites where the tower and shelter earths are kept separate — they must be bonded
- Operator-specific requirements that exceed this pack; the operator's specification governs
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 |
|---|---|---|
| Earth electrode | Ring around the tower and shelter, bonded together, with rods at tower legs | ITU-T K.56 |
| Target earth resistance | 10 Ω or lower; many operators specify 5 Ω or lower | ITU-T K.56 · operator specification |
| Feeder earthing | Earthing kits on each coaxial feeder at the top, at the bottom of the vertical run and at shelter entry | ITU-T K.56 |
| Bonding | Master earth bar at the cable entry; all racks, trays and the −48 V return bonded to it | ITU-T K.27 |
| Power SPD | Type 1+2 at the AC incomer; DC SPD on the −48 V plant | IEC 61643-11 · ITU-T K.56 |
| RF and data SPD | Coaxial SPDs matched to frequency band and connector; data-line SPDs | IEC 61643-21 |
| Aviation lighting | Obstruction lights where height and location require | ICAO Annex 14 |
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 |
|---|---|---|
| Earthing Kits | Ring earth, rods, feeder earthing kits and bars | One site kit; one feeder kit per feeder per earthing point |
| Data, Signal & RF Line SPDs | Coaxial surge protection at shelter entry | One per feeder |
| Low-voltage DC SPDs (24–220 V) | −48 V DC surge protection for the power plant and remote radio units | One per DC feed |
| Aviation Obstruction Lights | Tower obstruction lighting | From tower height and the aviation requirement |
| Lightning Strike Counters | Count strikes to the tower | One per tower |
From design to handover
- Survey soil resistivity and design the ring earth for the target resistance
- Install the ring, bond the tower legs and shelter, and fit the master earth bar
- Earth each feeder at the top, bottom and entry
- Fit AC, DC, RF and data surge protection
- Measure earth resistance and bonding continuity and record for the site file
Services for this solution
Industries that use it
Telecom OEMNetwork EquipmentDigital & Telecom Infrastructure
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 |
|---|---|---|
| CEA Safety Regulations 2023 | Reg 70(2) | A telecommunication line carried on power-line supports is protected against lightning in line with the relevant standards. |
| 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. |
| IEC 60364-6:2016 | Annex C | Earth electrode resistance is measured by fall-of-potential with auxiliary electrodes, by a loop impedance instrument, or by current clamps where auxiliary electrodes cannot be placed. |
| CEA Safety Regulations 2023 | Reg 43(x), Reg 50(8) | Earthing systems are tested for resistance on a dry day in the dry season at least once a year, and the records are kept for the Electrical Inspector. |
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 62305-4:2024 · LPES Knowledge Hub H-44
Reducing overvoltages in cables on masts and process vessels bonded ducting and inherent shielding (Figures B.7, B.8)
Cables that run on the outside of a mast or a process vessel — to an aerial, a meteorological sensor, a level transmitter, a valve position indicator — sit in one of the most exposed positions a cable can occupy: outside the structure's own conductive envelope, often on a tall or isolated item of steel that is itself a preferred lightning attachment point. Clause B.11.4 of Annex B gives the practical answer for retrofitting protection to these cables on an existing structure: run them in bonded ducting, trunking or metal tubes wherever possible, and where a fully enclosed duct is not practical — as on a process vessel — use the structure's own steel (rung ladders, pipes, well-bonded conducting materials) as a natural shield by routing the cable close against it. On a lattice mast built from L-shaped corner members, the specific instruction is to place the cable in the inside corner of the L, because that geometry gives the cable the maximum shielding the steelwork can offer. The clause is illustrated by two named figures: Figure B.7, showing inherent shielding from bonded ladders and pipes on a process vessel, and Figure B.8, showing the ideal cable positions inside the corner of an L-girder on a steel lattice mast.
How it is applied
- Identify every cable serving externally installed equipment on a mast or process vessel — antenna feeders, sensor signal cables, camera power and data, instrumentation loops.
- Wherever a fully enclosed route is achievable, specify bonded ducting, trunking or a metal tube for the cable run, bonded to the structure, and route all cables leading to a given item of equipment so that they leave the duct at a single point (this limits the number of places where a cable transitions from the shielded to the unshielded environment, each of which is a potential coupling point).
- Where a fully enclosed duct is not practical — the explicit process-vessel case named in B.11.4 — route the cable on the outside of the structure but as close as possible to existing conductive elements: rung ladders, pipe runs, and any other well-bonded conducting material, following the alternative positions shown in Figure B.7.
- Confirm that the conductive elements being used for inherent shielding (ladders, pipes) are themselves properly bonded to the structure's bonding network — an unbonded ladder or an isolated pipe section provides no inherent shielding benefit and may itself become a hazard.
- On a steel lattice mast with L-shaped corner members, route cables into the inside corner of the L wherever the mechanical arrangement allows it (Figure B.8), since this position is identified as giving maximum protection; where the inside-corner position is not achievable, use a bonded cable tray within the mast structure as the alternative shown in the same figure.
- Treat this clause's guidance as a retrofit measure to be combined with, not substituted for, the separation-distance requirement of B.11.3 and the SPD protection at the equipment — inherent shielding reduces the induced overvoltage reaching the cable, it does not by itself eliminate the need for an SPD at the equipment served by that cable.
Common mistakes
- Running a cable in free air alongside a process vessel or mast, at a distance from any conductive structure, when a bonded ladder, pipe run or L-girder corner was available and would have provided inherent shielding at no extra material cost.
- Using an unbonded or poorly bonded ladder or pipe as the "shielding" element — B.11.4's guidance depends on the conductive element being well bonded; an isolated conductor does not provide the inherent shielding the clause describes and can itself pick up dangerous potential.
- On a lattice mast, running the cable along the outside face of an L-girder rather than into its inside corner — the outer face gives materially less surrounding steel and therefore less shielding benefit than the position Figure B.8 identifies as ideal.
- Treating inherent shielding as a substitute for SPD protection at the equipment, rather than as a complementary measure that reduces (but does not eliminate) the induced voltage the SPD then has to handle.
- Allowing cables from the same equipment to leave a bonded duct at multiple points rather than a single point, multiplying the number of shielded-to-unshielded transitions.
Design checklist
- Have all cables serving externally installed equipment on this mast or vessel been identified?
- Has bonded ducting, trunking or metal tube been specified wherever a fully enclosed route is achievable?
- Where a fully enclosed duct is not practical (e.g. a process vessel), has the cable route been placed as close as possible to existing bonded conductive elements — ladders, pipes, other well-bonded conducting materials — per Figure B.7?
- Has the bonding of those ladders/pipes to the structure's bonding network been confirmed, not assumed?
- On a steel lattice mast with L-shaped corner members, has the cable been routed into the inside corner of the L wherever mechanically possible, per Figure B.8, with a bonded cable tray as the documented alternative where it is not?
- Do all cables serving a given item of equipment leave any bonded duct at a single point rather than multiple points?
- Has SPD protection at the point the cable enters the protected structure been specified separately, rather than relying on inherent shielding alone?
- Has separation distance to the LPS been checked and documented separately the related topic H-43, since B.11.4 addresses a different protection mechanism?
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
- 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
What earth resistance does a telecom site need?
10 Ω or lower is the usual reference; many operators ask for 5 Ω or lower. The operator's specification governs. Earth Resistance Testing
Why earth the feeder cable in several places?
Each earthing kit diverts part of the lightning current from the feeder screen to the tower before it reaches the equipment. Earthing Kits
Do I need coaxial surge protectors?
Yes, at the shelter entry, matched to the frequency band and connector type. Data, Signal & RF Line SPDs
How is the −48 V plant protected?
With DC surge protective devices at the rectifier output and at long DC feeds to remote radio units. Low-voltage DC SPDs (24–220 V)
Who installs and commissions the system?
LPES or a certified installer, with test records handed over for the site file. Installation & Commissioning
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.
