Lightning Arrester Guide for Kerala Homes and Buildings
A lightning arrester is a metal terminal on the roof, connected by a conductor to an earth electrode, that catches a lightning strike and sends the current into the ground instead of through your building. This guide covers what it is, how it works, the two types you will be offered, ELSAFE’s packages, and what Indian standard IS 2309 requires for a house, flat, school or factory in Kerala.
At a glance
What is a lightning arrester?
The term is used for two different devices. A complete lightning protection system uses both.
The rooftop arrester (air terminal)
A rod or ESE head on a mast at the highest point of the building. It intercepts the direct strike. This is what Kerala homeowners mean by “lightning arrester for a house”.
The panel-side arrester (surge arrester / SPD)
A small device inside the distribution board that clamps the voltage surge a strike induces in the wiring. It protects the inverter, TV and computers; it does nothing against a direct hit.
How a lightning arrester works
Every arrester works on one principle: very high resistance in normal conditions, very low resistance the instant a surge appears.
Interception
The terminal, the highest conductive point, launches an upward streamer that meets the descending leader, so the strike attaches to it instead of the roof.
Conduction
A down conductor, typically a 50SQmm OR 20 × 3 mm copper or GI strip, carries the current down the outside wall by the shortest straight route.
Dispersion
An earthrod or electrode dumps the current into the ground. IS 2309 requires the whole system to measure 10 ohms or less.
Recovery
The arrester returns to its high-resistance state, ready for the next strike. A well-made unit survives many strikes.
The design pulse in IEC 62305 is 10/350 microseconds with peaks up to 200 kA. Getting that to earth without a side-flash into pipes, rebar or wiring is why bonding and earthing matter as much as the rod itself.
Lightning arrester types: conventional vs ESE
Conventional (Franklin rod)
A pointed copper or copper-bonded rod, 1–2 m tall, on a mast. It protects a cone below it (IS 2309 uses a 45° angle) or, in modern design, the rolling-sphere zone. Simple, proven, fully covered by IS/IEC 62305 and the cheapest option. A large roof needs several rods joined by a conductor mesh.
ESE (early streamer emission)
An ESE head launches its upward streamer earlier than a plain rod, so one unit claims a wider radius. Units are qualified under NF C 17-102 and UNE 21186: advance time above 10 µs plus salt-mist, sulphur-atmosphere and three 100 kA impulse tests. ELSAFE supplies the LSG PROTECT ThunderGuard ELITE and the Alltec TerraStreamer.
The honest caveat. IEC 62305-3 sizes an ESE head as a plain rod of the same height, and a 2000 NIST review called the scientific basis for ESE claims “far from certain”. ESE is legal and widely used in India and suits large open sites. Our advice: insist on the NF C 17-102 test certificate, and for a critical building treat the ESE radius as a margin, not the design basis.
ELSAFE lightning arrester packages
| Package | Arrester and stated radius* | Down conductor | Earthing | Surge arrester | Extras | Price |
|---|---|---|---|---|---|---|
| Teksai Premium | Teksai TEK1000 spherical gap, 20 m | 25 m of 50 mm² copper cable, HDPE clamps | 2 × 2 m copper-bonded rods with Teksai graphite compound | LSG 50 kA, Class 1+2, three-phase | — | ₹73,350 |
| Teksai Ultimate | Teksai TEK1000 spherical gap, 20 m | 25 m of 50 mm² copper cable, HDPE clamps | 2 × 2 m copper-bonded rods with Teksai graphite compound | LSG 100 kA, Class 1+2, three-phase | Strike counter | ₹93,350 |
| LSG ESE | LSG PROTECT ThunderGuard ELITE ESE, 60 m | 25 m of 50 mm² copper cable, stainless clamps | 2 × 2 m copper-bonded rods with Teksai graphite compound | LSG 50 kA, Class 1+2, three-phase | — | ₹91,750 |
| LSG France Ultimate | LSG PROTECT ThunderGuard ELITE ESE, 60 m | 25 m of 50 mm² copper cable, stainless clamps | 2 × 2 m copper-bonded rods with Teksai graphite compound | LSG 100 kA, Class 1+2, three-phase | Strike counter, EQB50 equipotential bonding | ₹1,05,750 |
| ALLTEC USA ESE | Alltec TSP20 ESE, 60 m | 25 m of 50 mm² copper cable, HDPE clamps | 2 × 2 m copper-bonded rods with Teksai graphite compound | LSG 100 kA, Class 1+2, three-phase | Strike counter | ₹1,25,750 |
| ALLTEC USA Ultimate | Alltec TSP20 ESE, 60 m | 25 m of 70 mm² copper cable, stainless clamps | 2 × 2 m copper-bonded rods with Teksai graphite compound | LSG 100 kA, Class 1+2, three-phase | Strike counter, EQB50 bonding, exothermic earthing bonds | ₹1,56,250 |
All packages include a fibre-reinforced non-conductive mast with GI mast and base, earthing to the NF C 17-102 standard and a 15-year replacement warranty on the arrester. Prices as listed on keralalightningprotection.com in September 2026 during a limited-period offer; installation and GST as quoted. *Manufacturer’s stated radius; actual coverage depends on mast height, protection level and site conditions.
What a Kerala building needs: IS 2309 essentials
India’s code of practice, IS 2309:1989, has largely been superseded by IS/IEC 62305, but it is still what most installers and inspectors work to, and its rules are easy to check on site.
- Terminal at the highest point, with no part of the roof more than 9 m from a conductor; corners first, then mid-points on long roofs.
- Conductor size 20 × 3 mm copper, aluminium or GI strip, or 8 mm rod. Use copper or copper-bonded near the coast.
- One down conductor per 30 m of perimeter, no more than 10 m apart on buildings taller than 20 m, routed outside the walls by the shortest straight path.
- Whole system earthed to 10 Ω or less. On laterite or rock, IS 2309 allows a ring conductor or drilled, backfilled electrodes and relaxes the 10 Ω figure.
- A test joint on every down conductor, an inspection and earth test at least every 12 months, and a log book.
- Bond all roof metal, and add SPDs on the incoming power line and, for solar, at the inverter.
Two Kerala points: coastal air is salt-laden, so use bimetallic connectors wherever aluminium meets copper; and earth resistance rises sharply in the dry months, which is why we put a chemical earthing electrode with backfill compound under every arrester we install.
Why this matters in Kerala
The highest strike frequency is in Kottayam and the midland-foothill belt, with Pathanamthitta, Idukki, Ernakulam and Thiruvananthapuram also named. The Kerala State Disaster Management Authority recommends a lightning arrester on the building and surge protectors on electrical lines, alongside the IMD’s Damini warning app. See what a complete lightning protection system costs in Kerala.
Frequently asked questions
Which type is best for a house in Kerala?
A conventional rod or small ESE unit on a 2–3 m mast, one or two 20 × 3 mm copper down conductors, a chemical earth pit and a Type 2 SPD at the meter board. Larger or coastal buildings need an IS/IEC 62305 design.
How many down conductors does my building need?
Under IS 2309, at least one per 30 m of perimeter and no more than 10 m apart on buildings over 20 m tall. A small house needs one; a 60 × 20 m apartment block needs at least six.
Sources: IS 2309:1989 (BIS); IEC/BS EN 62305; NIST, Early Streamer Emission Lightning Protection Systems (2000); Centre for Earth Science Studies via The Wire Science; NCRB 2023 via Down To Earth; Kerala State Disaster Management Authority.
Get an IS/IEC 62305 design for your building
ELSAFE Protection & Control Systems, Kochi, has installed lightning protection and earthing at more than 1,000 sites across South India.
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