S Protection Distance
An S protection distance must always be maintained between the lightning down conductor, the building structure, and electrical cables according to IEC 62305 standards. In addition to the thermal effect of lightning strikes reaching up to 28,000 °C, the magnetic effect can damage our equipment. Therefore, the S protection distance is required. If this distance cannot be maintained during the down conductor installation, insulated lightning down conductors should be used.
How is S Distance Calculated?
S Distance Formula
- kc: Depends on down conductor design.
- ki: Depends on protection class.
- km: Depends on system materials.
- l: Distance to the nearest potential equalization point.
Protection Class Table
Protection Class Table
Calculation of kc
- h: Total number of conductors
- c: Distance between down conductors
- h: Distance between ring conductors
If the S Protection Distance cannot be maintained, an Insulated Lightning Down Conductor System must be used.
For HVI and ISCON insulated lightning down conductors and system design, please contact the Lightning Protection Center expert engineers. For fire and magnetic field protection, do not install bare copper conductors without proper calculations. Technical analyses are mandatory according to IEC standards.
Calculation of S distance
Use an Insulated Lightning Down Conductor System if S Distance cannot be maintained
