Siemens Simatic S7-300 CPU 31xC Series - Rules for the Transition Point between Lightning Protection Zones 1 - 2 and Higher

Appendix
A.3 Lightning and surge voltage protection
S7-300, CPU 31xC and CPU 31x: Installation
A-22 Operating Instructions, Edition 08/2004, A5E00105492-05
Consec.
no.
Cables for ... ... ... equip transition point 0 <-> 1 with: Order number
2 24 VDC power supply 1 x Blitzductor VT,
Type A D 24 V -
918 402*
3 MPI bus cable, RS485, RS232 (V.24) 1 x Blitzductor CT lightning
conductor, type B
919 506* and
919 510*
4 Inputs/outputs of 24 V digital modules DEHNrail 24 FML 909 104*
5 24 VDC power supply module 1 x Blitzductor VT
Type A D 24 V -
918 402*
900 111*
5SD7 032
6 Inputs/outputs of digital modules and
120/230 VAC power supply
2 x DEHNbloc/1 lightning conductor 900 111*
5SD7 032
7 Inputs/outputs of analog modules up to
12 V +/-
1 x Lightning conductor
Blitzductor CT type B
919 506* and
919 510*
* You can order these components directly from:
DEHN + SÖHNE
GmbH + Co. KG
Elektrotechnische Fabrik
Hans-Dehn-Str. 1
D-92318 Neumarkt
A.3.4 Rules for the transition point between lightning protection zones 1 <-> 2 and
higher
Rules for transition points 1 <-> 2 and higher (local equipotential bonding)
The following measures must be taken on all transition points 1 <-> 2 and higher:
• Set up local equipotential bonding at each subsequent lightning protection zone
transition.
• Include all lines (also metal conduits, for example) in the local equipotential bonding of all
subsequent lightning protection zone transition points.
• Include all metal installations located within the lightning protection zone in the local
equipotential bonding (for example, metal part within lightning protection zone 2 at
transition 1 <-> 2).
Additional Measures
We recommend fine-wire fusing for following elements:
• All 1 <-> 2 and greater lightning protection zone transitions
• All cables that run within a lightning protection zone and are longer than 100 m
Lightning protection element for the 24 VDC power supply module.
Always use the Blitzductor VT, type AD 24 V SIMATIC for the 24 VDC power supply module
of the S7-300. All other surge protection components do not meet the required tolerance
range of 20.4 V to 28.8 V of the S7-300 power supply.