Assembling and Installing Systems
A-23
AutomationSystem S7-400 Hardwareand Installation
A5E00850741-01
A.9.2 Rules for the Transition between Lightning Protection Zones0and1

Rule for the Transition0 < ->1 (Lightning Protection Equipotential Bonding)

The following measures are suitable for lightning protection equipotential bonding
at the transition between lightning protection zone 0 <-> 1:
•Use grounded, spiralled, current-conducting metal strips or metal braiding, for
example, NYCY or A2Y(K)Y,as a cable shield at the start and end
•Lay the cables in one of the following ways:
-- in continuous metal pipes that are grounded at the start and end
-- in ducts of armored concrete with continuous armoring
-- on closed metal cable racks grounded at the start and end
•Use fiber-optic cables instead of lightning stroke current-carrying cables.

Additional Measures

If you cannot take the measures listed above, you must install a high-voltage
protector at transition 0 <->1 with a relevant lightning conductor.Table A-3 contains
the components you can use for high-voltage protection of your plant.
TableA-3 High-VoltageProtection of Cables with the Help of Surge Protection Equipment
Ser.
No.
Cablesfor ... ... equiptransition point 0 < -->1
with:
OrderNo.
13-phase TN-C system 1pieceof DEHNbloc/3lightning
conductor
phase L1/L2/L3 to PEN
900 110*
5SD7 031
3-phase TN-S system 1pieceof DEHNbloc/3lightning
conductor
phase L1/L2/L3 to PE
900 110*
5SD7 031
1pieceof DEHNbloc/1lightning
conductor
NtoPE
900 111*
5SD7 032
3-phase TT system 1pieceof DEHNbloc/3lightning
conductor
phase L1/L2/L3 toN
900 110*
5SD7 031
1pieceof DEHNgapB/n N-PE light-
ning conductor
NtoPE
900 130*
AC TN-S system 2 pieces of DEHNbloc/1 lightning
conductor
phase L1 + N to PE
900 111*
5SD7 032
AC TN-C system 1pieceof DEHNbloc/1 lightning
conductor
phase L to PEN
900 111*
5SD7 032