ABB DCS800 Series Installation Manual page 53

Note:
The paint should be removed to allow a good connection to the cabinet frames
throughout the whole perimeter of the metal conduit (or a bus duct). The metal
conduit (or the bus duct metal) should be electrically continuous throughout its
complete length.
Cable Bus System
Connection of a high current (> 300 A) cable bus system that consists of several
cables (see
Note:
It is recommended to arrange the cables
alongside as shown to achieve a current
distribution as accurate as possible. Air
between cables is required for cooling.
High-current cable bus connection
Note:
Current derating of the cables is required when installing the cables in a cable tray.
This derating factor must be taken into account as per the local electrical safety
codes.
In case metallic cable entries (e.g. EMC-cable entry) are used all three phases (L1,
L2, L3) have to be routed together through one single drilling hole:
L2
If the phases are routed separately, means each phase uses its own drilling hole,
then the metal will be heated due to circulating currents.
Single-core Cables with Concentric Protective Shields
When single-core cables equipped with concentric protective shields (metal) are
used, the phase current will induce voltage to the cable shield. If the shields are
connected to each other at both ends of the cable, current will flow in the cable
shield. In order to prevent this and to ensure personal safety, the cable shield must
be connected only to PE at the transformer side and insulated on the converter side
(see High-current single-core cable
High-current cable bus
L1 L1
L3 L2 L3
Bottom_plate EMC_cable entry_a.dsf
3ADW000352R0101 DCS800-A Installation Manual e a
connection)
L1
L2 L3
connection).
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Electrical Installation