
3. INSTALLATION
B–63323EN/03
18
D The ground resistance of the protective earth (PE) system must be
100 Ω or less (as per class–D grounding).
D The connection cable for the protective earth (PE) system must be so
large in cross section that the accidental current can flow through the
protective earth (PE) system safely in the event of an accident such as
a short–circuit.
(In general, the cross section must be equal to or greater than that of
the AC power line.)
D The connection cable for the protective earth (PE) system must be
integral with the AC power line so that the power is not supplied when
the grounding line is disconnected.
(a) Control unit
Connect the 0V line of the electronic circuits inside the control unit to
the earth plate on the cabinet via the signal ground (SG) terminal
(bottom front of main board).
Signal
ground
(SG)
M4
(mounting
hole)
M3
(screw
terminal)
SG
M3
Earth cable
System ground
Cabinet ground plate
Earth cable
(Twisted wire earth cable lead
2mm
2
or more)
Plate
NOTE
Connect an twisted wire earth cable lead 2mm
2
or more to
the earth plate on the cabinet keeping the lead as short as
possible.
Notes on wiring for the
grounding systems
3.6.3
Grounding Units