Appendix
A.2 Protection against electromagnetic interference
S7-300, CPU 31xC and CPU 31x: Installation
A-16
Operating Instructions, Edition 08/2004, A5E00105492-05
A.2.8
Cable routing inside buildings
Introduction
Inside buildings (inside and outside cabinets), clearances must be maintained between
groups of different cables to achieve the necessary electromagnetic compatibility (EMC).
The table contains information on the general rules governing clearances to enable you to
choose the right cables.
How to read the table
To find out how to run two cables of different types, proceed as follows:
1. Look up the type of the first cable in column 1 (Cables for ...).
2. Look up the type of the second cable in the corresponding field in column 2 (and cables
for ...).
3. Note the applicable directives in column 3 (Run ...).
Table A-7
Cable routing inside buildings
Cables for ...
and cables for ...
Run ...
•
Bus signals, shielded (PROFIBUS)
•
Data signals, shielded
(programming devices, operator
panels, printers, counter inputs,
etc.)
•
Analog signals, shielded
•
DC voltage ( ≤ 60 V), unshielded
•
Process signals ( ≤ 25 V), shielded
•
AC voltage (≤ 25 V), unshielded
•
Monitors (coaxial cable)
In common bundles or cable ducts
•
DC voltage (> 60 V and ≤ 400 V),
unshielded
•
AC voltage (> 25 V and ≤ 400 V),
unshielded
In separate bundles or cable ducts (no
minimum clearance necessary)
•
Bus signals, shielded (PROFIBUS)
•
Data signals, shielded
(programming devices, operator
panels, printers, counter inputs,
etc.)
•
Analog signals, shielded
•
DC voltage ( ≤ 60 V), unshielded
•
Process signals ( ≤ 25 V), shielded
•
AC voltage (≤ 25 V), unshielded
•
Monitors (coaxial cable)
•
DC and AC voltage (> 400 V),
unshielded
Inside cabinets:
In separate bundles or cable ducts (no
minimum clearance necessary)
Outside cabinets:
On separate cable racks with a
clearance of at least 10 cm
