Cable Bus System; Single Core Cables With Concentric Protective Shields - ABB ACS800 Series Hardware Manual

Cable bus system

The connection of a high current (> 300 A) cable bus system that consists of several
cables is represented below. In this system, less conductor material is needed due
to better cooling of separate conductors.
L1
L1
L3 L2
L3 L2
L2
L1 L2 L3 L1
N
It is recommended to arrange the cables as shown
– alongside each other – to achieve a current
distribution as accurate as possible. Gaps between
cables are required for cooling.

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.
The connection is represented below.
Concentric shield
L1
L3 L2
L3 L2 L3
L1 N
N
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 code.
Line cpl transformer
Line coupling
transformer
L1
L2
L3
N
PE
Site main earthing bus
L1
L2
L3
N
PE
Site main earthing bus
Converter
L1
L2
L3
PE
Converter
L1
L2
L3
PE
Planning the electrical installation
63