Installation manual

Assembling and Installing Systems
A-23
S7-400 and M7-400 Programmable Controllers Hardware and Installation
A5E00069481-04
A.9.2 Rules for the Transition between Lightning Protection Zones
0 and 1
Rule for the Transition 0 <-> 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.
Table A-3 High-Voltage Protection of Cables with the Help of Surge Protection Equipment
Ser.
No.
Cables for ... ... equip transition point 0 <–> 1
with:
Order No.
1 3-phase TN-C system 1 piece
of
DEHNbloc/3 lightning con-
ductor
phase L1/L2/L3 to PEN
900 110*
5SD7 031
3-phase TN-S system 1 piece
of
DEHNbloc/3 lightning con-
ductor
phase L1/L2/L3 to PE
900 110*
5SD7 031
1 piece
of
DEHNbloc/1 lightning con-
ductor
N to PE
900 111*
5SD7 032
3-phase TT system 1 piece
of
DEHNbloc/3 lightning con-
ductor
phase L1/L2/L3 toN
900 110*
5SD7 031
1 piece
of
DEHNgap B/n N-PE light-
ning conductor
N to PE
900 130*
AC TN-S system 2 pieces
of
DEHNbloc/1 lightning con-
ductor
phase L1 + N to PE
900 111*
5SD7 032