Siemens SIMATIC ET 200iSP Operating Instructions Manual page 444

Appendix
A.5 Lightning and overvoltage protection
Effect of the lightning strike
Direct lightning strikes occur in lightning protection zone 0
high-energy lightning currents and strong electromagnetic fields. As direct lightning strikes only
occur in lightning protection zone 0
Only lightning protection zone transitions from 0
Effects are to be reduced from one lightning protection zone to the next lightning protection
zone by means of suitable lightning current or combined lightning current arresters or shielding
measures.
As described in EN 1127-1, direct lightning strikes ignite potentially explosive atmospheres.
Permanently effective lightning protection systems are therefore mandatory for such
installations according to current lightning protection standards.
Overvoltages
Electromagnetic fields of the lightning channel can be reduced with appropriate shielding
measures. Overvoltages caused by inductions can be reduced to a harmless level from lightning
protection zone 0
444
(as described in the next section), they are not considered.
A
by means of overvoltage suppressors.
B
. Effects of the lightning strike are
A
to 1 and higher are considered.
B
Operating Instructions, 11/2022, A5E00247483-AK
ET 200iSP