A. Install vertically if practicable, then at not more than a 45-degree angle if not
practicable to install vertically, then in a ditch at least 21⁄2 ft (750 mm) deep if not
practicable to install at not more than a 45-degree angle.
B. In dry or arid regions, it is required to install rods that are longer than 8 ft to reach
permanent moisture level.
C. First measure the resistance of the first ground rod, and install additional rods until
the resistance of the group is 25 ohms or less.
D. It is permitted to install the rod vertically, at not more than a 45-degree angle or in a
ditch at least 21⁄2 ft (750 mm) deep, at the installer’s option.