Limit of the advance at the start-up according to standard NF C 17-102:2011

Introduction

rods lightningEarly streamer emission (ESE)rely ona key principle: triggering the upward leader more quickly than franklin simple rod. This time saving is called the early streamer emission (ESE) lead.
However, to prevent commercial excesses and guarantee the safety of installations, the NF C 17-102:2011 sets a clear limit: ΔT ≤ 60 microseconds.

What is the ignition advance (ΔT)?

• The ΔT (expressed in µs) measures the time saved compared to a simple tip.
• This parameter is integrated into the standardized formula for calculating the protection radius (Rp).
• However, roleplay depends on three inseparable factors :
  1. The ΔT of the lightning rod (10, 25, 45 or 60 µs)
  2. The installation height (h) above the area to be protected
  3. The level of protection defined by the standard (I, II, III, IV) corresponds to the severity of the risk to be covered.

👉 Simplified example:

• A ESE with ΔT = 60 µs installed at a height of 5 m will not give the same Rp as a ESE with ΔT = 60 µs installed at 20 m.
• Similarly, a protection level I (the most demanding) reduces the Rp compared to level IV.

The limit imposed by the NF C 17-102:2011 standard

• The standard sets ΔT max = 60 µs.
• This ceiling is essential because:
  1. Beyond that, the results are not scientifically reliable.
  2. He avoids announcing unrealistic and dangerous rays.
  3. It guarantees a common base for all manufacturers.

⚠️ Warning: the protection radius should never be stated solely based on ΔT. It must always be calculated according to the standard's formula, taking into account the chosen protection level.

The case of LPS France products

At LPS France, all our PDAs comply with the NF C 17-102:2011 standard.

• We offer a complete range: ΔT = 10, 25, 45 and 60 µs.
• Our technical documents systematically specify the Rp values ​​according to:
  • the ΔT,
  • the installation height,
  • and the level of protection (I to IV).

👉 Our top-of-the-range Paraton@ir goes further: in addition to being compliant, it is connected via LPS Manager, allowing real-time monitoring and traceability of lightning strikes.

Conclusion

The 60 µs , as defined by standard NF C 17-102:2011, guarantees reliability and safety.
However, it's essential to remember that the protection radius (Rp) also depends on the installation height and the chosen protection level.
👉 With its compliant product ranges and connected solutions, LPS France ensures reliable, transparent, and innovative protection.