Hitachi LQE550, User Manual

Page: 44 / 99

3 MOUNTING AND WIRING
3-7
3.3.3 Ground wiring
Carry out ground wiring as shown in Figure 3-4 by following these steps:
①
Connect the FG terminals of the power supply module, CPU or LPU module and optional
modules by crossover wiring to the mount base’s grounding point, a hexagon nut fitted to the
mount base FG terminal (with a wire diameter of 2.0 mm
2
or more).
②
Wire the mount base FG terminal to the PCs unit grounding point of the enclosure in which
the mount base is housed (with a wire diameter of 2.0 mm
2
or more).
③
Perform Class D grounding from the PCs unit grounding point of the enclosure using a wire
with a wire diameter of 5.5 mm
2
or more.
Figure 3-4 Ground Wiring
* Class D grounding is defined in the Technical Standard for Electrical Facilities of Japan.
This standard states that the grounding resistance must be 100 ohms or less for equipment
operating on 300 VAC or less, and 500 ohms or less for devices that shut down
automatically within 0.5 seconds when shorting occurs in low tension lines.
FG terminal to each
individual module
CPU LINK module
Mount base FG
terminal
To mount base
FG terminal
Enclosure’s PCs unit
grounding point
2.0 mm
2
or more
Class D
grounding*
2.0 mm
2
or more
5.5 mm
2
or more