Siemens SIMATIC NET Instrucciones de operaciones descargar pdf (Pagina 169)

Guidelines for Installing Networked Automation Systems in Buildings

7-21

SIMATIC NET Twisted-Pair and Fiber-Optic Networks

C79000-G8976-C125-02

7.4.3 Cabling within Closets

When running cables within cubicles and cabinets, remember the following rules:

S Install the cables in metallic, electrically conductive cable channels.

S Screw the cable channels to the struts of the rack or cubicle walls

approximately every 50 cm making low-resistance and low-inductance contact.

S Separate the cables according to the categories as shown in table 7-1 .

S Maintain the minimum clearance between the cables of different categories as

explained in table 7-1 . In general, the risk of interference due to crosstalk is

less the greater the clearance between the cables.

S Where cables of different categories cross, they should cross approximately at

right angles (wherever possible avoid sections where the cables run parallel).

S The shields of all cables entering the wiring closet should make large-area

contact with closet ground as close as possible to the point of entry.

7.4.4 Cabling within Buildings

When laying cables outside cabinets but within buildings, note the following points:

S Lay the cables in metallic, electrically conducting cable channels.

S Include the metal cable channels and racks in the bonding system of the

building or plant. Note the information on equipotential bonding in Section 7.3 in

this manual.

S Separate the cables according to the categories as described in table 7-1 and

run the various categories in their own channels/racks.

S If there is only one common metal channel available for all categories, either the

clearances shown in Table 7-1 must be maintained or the individual categories

should be separated from each other by metallic partitions. The partitions must

be connected to the channel making low-resistance and low-inductance

contact.

S Cable racks should cross each other at right angles.

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Siemens SIMATIC NET Instrucciones de operaciones Pagina 169