Panasonic KX-HTS Series Manual page 44

3.2.8 Surge Protector Installation
Outside Installation
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 is different from that for trunks.
Installation of an Earth Rod
1. Connect the earth rod to the surge protector using an earthing wire with a cross-sectional area of at least
1.3 mm2.
2. Bury the earth rod near the protector. The earthing wire should be as short as possible.
3. The earthing wire should run straight to the earth rod. Do not run the wire around other objects.
4. Bury the earth rod at least 50 cm underground.
Note
• The above figures are recommendations only.
• The length of earth rod and the required depth depend on the composition of the soil.