Panasonic KX-TD500 System Reference Manual page 171

5.00 Installation of an Earth Rod
Lightning
Protector
CO
Grounding
Wire
(Underground)
1) Installation location of the earth rod ....................Near the protector
2) Check obstructions .............................................None
3) Composition of the earth rod...............................Metal
4) Depth of the earth rod .........................................More than 50 cm
5) Size of the grounding wire ..................................Thickness is more
Notes • The above figures are recommendations only.
• The length of earth rod and the required depth depend on the
composition of the soil.
Main
Unit
Earth Rod
2-G-3
(20 inches)
than 16 AWG