The choice of LED lighting technology is often driven by the need of long duration operation. But the LED technology faces threats due to lightning surges which could reduce drastically the life duration. Due to its external location and its connection to wide AC network, the risk of surge on LED lighting system must be really taken in account.
All luminaires are connected to earthing systems. During near-by ligthning strike, partial impulse currents can reach every street lights and will rise the earth potential to huge values. Heavy surges voltage differences will occur on AC network, between active wires and Earth (Class I) or Functional Earth (Class II).
The implementation of dedicated Surge Protectors (SPDs) at the entrance of the LED system (inside the fixture) is necessary to improve safety and efficiency on the long duration required for lighting equipment.
The selection of the Surge Protectors for LED lighting system could be done following existing installation guides
Without SPD, a SMPS (Swiching Mode Power Supply) used for LED system has an impulse withstand (@ 1.2/50 µs) from 2.5 to 5 kV, depending of the technology. A Surge protection is required to withstand the standards and the real phenomena ( 10 kV). Implementing external SPD is the solution
SPD connected upstream the LED device allows