ABB ACS880-37 Hardware Manual page 77

Note: When continuous metal conduit is employed, shielded cable is not required. The
conduit must have bonding at both ends.
A four-conductor system is allowed for input cabling, but shielded symmetrical cable is
recommended.
Compared to a four-conductor system, the use of symmetrical shielded cable reduces
electromagnetic emission of the whole drive system as well as the stress on motor
insulation, bearing currents and wear.
The protective conductor must always have an adequate conductivity. The table below
shows the minimum cross-sectional area related to the phase conductor size according to
IEC 61439-1 when the phase conductor and the protective conductor are made of the
same metal.
Cross-sectional area of the phase conductors
S (mm
16 < S < 35
35 < S < 400
400 < S < 800
2
)
S < 16
Guidelines for planning the electrical installation 77
Minimum cross-sectional area of the
corresponding protective conductor
2
S (mm )
p
S
16
S/2
200