Siemens SIMATIC S7-400 Hardware And Installation Manual page 255

A.5.1 Lightning Protection Zone Concept
Principle of the Lightning Protection Zone Concept
The principle of the lightning protection zone concept states that the volume to be
protected, for example, a manufacturing hall, is subdivided into lightning protection
zones in accordance with EMC guidelines (see Figure A-4).
The individual lightning protection zones are constituted by:
The external lightning protection of the building (field side)
The shielding of
Buildings
Rooms and/or
Devices
Effects of a Lightning Strike
Direct lightning strikes occur in lightning protection zone 0. The lightning strike
creates high-energy electromagnetic fields which can be reduced or removed from
one lightning protection zone to the next by suitable lightning protection
elements/measures.
Surges
In lightning protection zones 1 and higher, surges can result from switching
operations and interference.
S7-400 and M7-400 Programmable Controllers, Installation Manual
C79000-G7076-C424-01
www.gkbpx.com
Assembling and Installing Systems
Lightning protection
zone 0
Lightning protection
zone 1
Lightning protection
zone 2
Lightning protection
zone 3
A-15