3-4
Connecting the Ground Wire
Connect the AC ground wire properly since it is crucial to lightning protection and electromagnetic
susceptibility (EMS).
The power input end of the AC is connected with a noise filter, whose central ground is directly
connected to the chassis, forming the chassis ground (also known as PGND). This chassis ground must
be securely grounded so that induced and leaked electricity can be safely discharged to the ground,
enhancing the EMS capability of the AC. Ground the AC as follows:
z
When a grounding strip is available, attach one end of the yellow-green ground wire of the AC to
the grounding terminal on the grounding strip and fasten the captive nut. Note that the fire main and
lightning rod of a building are not suitable for grounding the AC. The ground wire of the AC should
be connected to the grounding device in the equipment room.
Figure 3-5
Ground the AC through a grounding strip
(1) AC power socket
(2) Grounding terminal
(3) Protection ground wire
(4) Grounding strip
z
When there is no grounding strip but earth is available nearby and allows a grounding body to be
buried, hammer an angle steel or steel pipe longer than 0.5 m (1.64 ft) into the earth. In this case,
weld the yellow-green ground wire of the AC onto the angle steel or steel pipe, and treat the joint for
corrosion protection.