HANDBOOK REQUIREMENTS - Central Maine Power Company
HANDBOOK REQUIREMENTS - Central Maine Power Company
HANDBOOK REQUIREMENTS - Central Maine Power Company
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2. Metal frame of building or structure, where<br />
effectively grounded.<br />
3. Concrete-encased electrode consisting of at least 20<br />
feet of 1/2 inch reinforcing bar or #4 AWG copper wire<br />
encased within and near the bottom of a concrete footing or<br />
foundation.<br />
4. Ground ring consisting of a minimum of 20 feet of bare<br />
copper wire not smaller than #2 AWG, in direct contact<br />
with the earth, buried at least 30 inches deep all the way<br />
around the building or structure.<br />
5. Driven ground rod or pipe, which must be at least 8<br />
feet long; consisting of rod not smaller than 5/8 inch<br />
diameter made of galvanized steel, or copper clad steel; or<br />
pipe not smaller than 3/4 inch trade size and protected from<br />
corrosion. At least 8 feet of electrode must be in contact<br />
with the soil, and it must be driven vertically or up to a 45°<br />
angle where rock is encountered. As an alternative, the<br />
electrode may be buried in a trench that is at least 30 inches<br />
deep. See Notes 1 and 2, below.<br />
6. Other listed electrodes for grounding shall be<br />
permitted.<br />
7. Metal plate electrode with at least 2 square feet of<br />
surface in contact with soil and buried at least 30 inches<br />
deep. Iron or steel plates shall be at least ¼ inch thick;<br />
nonferrous plates at least 0.06 inch thick. See Notes 1 and<br />
2, below.<br />
8. Local underground metal piping system or tank (a gas<br />
piping system shall NOT be used as a grounding electrode).<br />
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