ABB ACQ810 - Planning the Cabinet Placement on a Cable Channel; Planning the Electro Magnetic Compatibility (EMC) of the Cabinet

Planning the cabinet installation 35
Planning the cabinet placement on a cable channel
Note the following when planning to place the cabinet on a cable channel:
• The cabinet structure must be sturdy enough. If the whole cabinet base will not be
supported from below, the cabinet weight must lie on the sections that the floor carries.
• The cabinet must have a sealed bottom plate and cable lead-throughs to ensure the
degree of protection, fire protection and EMC requirements.
Planning the Electro Magnetic Compatibility (EMC) of the
cabinet
Note following when planning the electromagnetic compatibility of the cabinet:
• Generally, the fewer and smaller the holes in the cabinet, the better the interference
attenuation. The maximum recommended diameter of a hole in galvanic metal contact
in the covering cabinet structure is 100 mm. Pay special attention to the cooling air
inlet and outlet gratings.
• The best galvanic connection between the steel panels is achieved by welding them
together as no holes are necessary. If welding is not possible, the seams between the
panels are recommended to be left unpainted and equipped with special conductive
EMC strips to provide adequate galvanic connection. Usually, reliable strips are made
of flexible silicon mass covered with a metal mesh. The non-tightened touch-contact of
the metal surfaces is not sufficient, so a conductive gasket between the surfaces is
required. The maximum recommended distance between assembly screws is
100 mm.
• Sufficient high-frequency grounding network must be constructed in the cabinet to
avoid voltage differences and forming of high-impedance radiator structures. A good
high-frequency grounding is made with short flat copper braids for low inductance.
One-point high-frequency grounding cannot be used due to the long distances inside
the cabinet.
• 360° high frequency grounding of the cable shields at the cable lead-throughs
improves the EMC shielding of the cabinet.
The carrying structure on a cable channel
Cables
Cabinet side view with a bottom plate
Cable channel