Panasonic KX-TDA30 Installation Manual page 67

Outside Installation
Surge Protector
Trunk
Terminal
Extn.
SLT
If you install an extension outside of the building, the following precautions are recommended:
a.
Install the extension wire underground.
b.
Use a conduit to protect the wire.
Note
The surge protector for an extension and CS is different from that for trunks.
Installation of an Earth Rod
Surge Protector
Trunk
Earthing
Wire
(Underground)
(Main Building)
Trunk
PBX
Board
Extn.
Extn.
PT CS
PBX
Earth Rod
2.2.12 Surge Protector Installation
(Another Building)
SLT
PT
Extn.
CS
Surge
Protector
Earth
Extn.: Extension Line
Installation Manual 67