ESE Lightning Arresters, also known as Early Streamer Emission Lightning Arresters, protect buildings from direct lightning strikes.
The goal of this device is simple. It increases the protection radius compared to conventional arresters, which reduces the number of arresters and down conductors needed for a building, all while ensuring full coverage.
It safely channels lightning bolts into the ground, preventing random strikes on structures or equipment.
In this blog, we’ll explore the testing requirements for ESE Lightning Arresters under the NFC 17-102:2011 standard.
What is NFC Standard?
The NFC 17-102:2011 standard is a set of guidelines and recommendations on how to design and install lightning protection systems using ESE arresters. It aims to make lightning protection safer and more effective.
Developed by France’s National Standard Committee (Commission UF 81), the standard covers how to select, position, install, and maintain ESE systems.
By defining operating conditions, testing protocols, and installation guidelines, it helps ensure ESE systems perform dependably during lightning strikes.
Operating Conditions
The standard defines normal operating conditions as temperature from minus 20 degree Celsius to plus 60 degrees Celsius, and wind speeds lower than 122 kilometres per hour. If conditions go beyond this range, such as extreme temperatures, strong winds, snow, ice, or heavy pollution, the arrester is considered to be in abnormal conditions. However, the standard requires it to remain reliable in both cases.
Testing Requirements – Annexure C of NFC 17-102
1. General Requirements
Every ESE arrester must be clearly labeled with the manufacturer’s name, logo, product reference, emission efficiency, and serial number.
2. Mechanical Requirements
Parts that carry lightning current must be made from solid materials with enough cross-section for safe conduction. These include copper, aluminium, stainless steel, or hot-dip galvanised steel, with at least 200 mm² of cross-section (16 mm diameter for rods).
3. Corrosion Resistance
Your ESE Lightning Arresters must resist corrosion. This is important in coastal zones, industrial sites, and polluted urban areas. To test this, there are two methods. First, the arrester is placed in a salt spray chamber, where it is exposed to a fine mist of sodium chloride solution. This creates a controlled environment that speeds up the effect of salty air on your arrester. This shows how the arrester handles long-term exposure to sea air. Second method, the arrester goes through a sulphur dioxide test under the NF EN ISO 6988 standard. It runs for seven cycles. Each cycle lasts 24 hours. For 8 hours, the arrester stays at 40 degrees Celsius in a humid atmosphere with 667 parts per million of sulphur dioxide. That means for every one million parts of air, there are 667 parts of sulphur dioxide mixed in. Then it rests for 16 hours before the cycle repeats.
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4. Current Withstand Capability
This test ensures, if the arrester can survive a real lightning strike. For this, they create a test current that acts like lightning. It rises very fast, within 10 microseconds, and reaches up to 100 kiloamperes. Then it slowly fades over 350 microseconds. The arrester is hit with this current three times. If it keeps working after all three, it passes the test.
This shows the arrester can handle multiple strikes, just like it might in real-world conditions. The arrester is allowed to cool between each strike. After the test, it must not have any damage or holes. Burn marks on the surface are fine. These checks prove that the arrester can carry real lightning current without failing.
5. Requirements for ESE
The early streamer emission is measured as a time difference, called delta T. It shows how early the ESE arrester responds compared to a conventional lightning rod under the same conditions. This time difference is recorded during testing and used to rate the Lightning Arrester’s performance.
Delta T must fall between 10 and 60 microseconds. If it is below 10, the device is not considered an ESE arrester. If it is above 60, the value is capped at 60 microseconds for all protection calculations. Delta T is important because it defines the protection radius. A higher delta T means the arrester reacts earlier and protects a wider area.
The components that capture the lightning strike, mainly the tip of the arrester, must meet the size and finish requirements given in NFC 17-102. The striking point must be made from solid metal with a smooth, continuous surface. If it has a coating, the minimum thickness must be 50 microns, and it must be free of defects like cracks or tarnishing. These checks make sure the arrester can take the full strike and stay intact.
6.Verification
Lightning protection systems are classified by risk, from level one to level four. Level one is for the highest risk, like tall buildings or sensitive sites. Level four is for low-risk areas like small structures.
The lightning protection system must be verified after the ESE Lightning Arrester is installed. It should also be checked at regular intervals, as specified in table 7 of the NFC 17-102 standard.
According to this table, for protection levels one and two, a visual check is needed every year and a full check in every two years. For levels three and four, the visual check is needed in every two years and the full check in every four years. Critical systems must be fully inspected every year, no matter the level.
We hope this gives you a clear understanding of ESE testing requirements. Axis ESE Arresters are independently type-tested and fully compliant with NFC 17-102.
Our 40+ engineers are ready to assist you in designing, installing, and testing your lightning protection system. Axis solutions have been installed in substations, data centres, factories, residential and commercial buildings.
Thank you for reading and if you found this informative, then feel free to contact us to get a quote or to know more about our products; visit our product section at https://axis-india.com/products/
