Siemens SIMATIC NET PROFIBUS User Manual

C-4

PROFIBUS Networks SIMATIC NET

6GK1970-5CA20-0AA1 Release 2 05/2000

Mechanical protection is required to protect LAN cables from breaks or mechanical
damage.

The guidelines for mechanical protection apply both to electrical and optical
cables.

The following measures are recommended to protect LAN cables from physical
damage:

S

When a cable cannot be installed on a cable rack or similar construction, it
should be installed in a conduit (for example PG 11-16).

S

In areas where the cable is subject to mechanical stress, install the cable in a
heavy-gauge aluminum conduit or in a heavy-gauge plastic conduit (see Figure
C-1)

S

When 90

°

 bends are necessary and at the junctions between buildings (for

example expansion joints), a break in the conduit is acceptable only when there
is no likelihood of damage to the cable, for example due to falling objects (see
Figure C-2).

S

In areas where the cable is likely to be walked on or driven over, the cable must
be protected from damage by a closed heavy-gauge aluminum or steel conduit.
As an alternative, the cable can be laid in a metal cable gutter.

Remember the instructions for laying cables outside buildings.

Figure C-1

Mechanical Protection of the LAN Cable