National Electrical Code - RCA DRD102RW Installation Manual

Appendix C/National Electrical Code 127
250-83. Made and Other Electrodes.
Where none of the electrodes specified in Section 250-81 is available, one or more of the electrodes specified in (b) through
(d)* below shall be used. Where practicable, made electrodes shall be embedded below permanent moisture level. Made
electrodes shall be free from nonconductive coatings, such as paint or enamel. Where more than one electrode is used, each
electrode of one grounding system (including that used for lightning rods) shall not be less than 6 feet (1.83m) from any other
electrode of another grounding system.
Clamps suitable
for direct burial
or exothermic weld
(c) Rod and Pipe Electrodes.
Rod and pipe electrodes shall not be less than 8 feet (2.44m) in length and shall consist of the following materials, and shall
be installed in the following manner.
(1) Electrodes of pipe or conduit shall not be smaller than 3/4-inch trade size and, where of iron or steel, shall have the
outer surface galvanized or otherwise metal-coated for corrosion protection.
(2)
Electrodes of rods of iron or steel shall be at least 5/8 inch (15.87mm) in diameter. Stainless steel rods less that 5/
8 inch (15.87) in diameter, nonferrous rods, or their equivalent shall be listed and shall not be less than 1£2inch
(12.7mm) in diameter.
(3)
The electrode shall be installed such that atleast 8 feet (2.44m) of length is in contact with the soil. It shall be driven
to a depth of not less than 8 feet (2.44m) except that, where rock bottom is encountered, the electrode shall be driven
at an oblique angle not to
exceed 45 degrees from the
vertical or shall be buried in
a trench that is at least 2 I£2
feet (762mm) deep. The
upper end of the electrode
shall be flush with or below
ground level unless the
above ground end and the
grounding electrode con-
ductor attachment are pro-
tected again stphysical dam-
age as specified in Section
250-117.