Siemens Automation System S7-400 - Manual (Page 191)

Assembling and Installing Systems
A-23
Automation System S7-400 Hardware and Installation
A5E00850741-01
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
conductor
phase L1/L2/L3 to PEN 900 110*
5SD7 031
3-phase TN-S system 1 piece of DEHNbloc/3 lightning
conductor
phase L1/L2/L3 to PE 900 110*
5SD7 031
1 piece of DEHNbloc/1 lightning
conductor
N to PE 900 111*
5SD7 032
3-phase TT system 1 piece of DEHNbloc/3 lightning
conductor
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
conductor
phase L1 + N to PE
900 111*
5SD7 032
AC TN-C system 1 piece of DEHNbloc/1 lightning
conductor
phase L to PEN 900 111*
5SD7 032