General Order 64-A

Original Version

Rule 21.8

21.8    Permanently Grounded means connected to earth in such a manner that no current which can flow in the ground wire will cause a harmful voltage to exist between the grounded conductors and facilities and adjacent exposed conducting surfaces which are in good contact with the earth, or with adjacent surfaces of earth itself, under the most severe conditions which are liable to arise in practice.

If a resistance of less than 25 ohms is not obtained, the equivalent of two ½ inch corrosion resisting rods, not less than 8 feet in length and continuous throughout, driven to a minimum depth of 8 feet at not less than 6 foot centers will considered a permanent ground for the purpose of these rules.

Strikeout and Underlined Version

Rule 21.8

21.8    Permanently Grounded means connected to earth in such a manner that no current which can flow in the ground wire will cause a harmful voltage to exist between the grounded conductors and facilities and adjacent exposed conducting surfaces which are in good contact with the earth, or with adjacent surfaces of the earth itself, under the most severe conditions which are liable to arise in practice.

For all circuits, other than a common primary and secondary grounded neutral distribution system of 5000 volts or less, if a resistance of less than 25 ohms is not obtained, measurement being made by any approved method, the equivalent of two ½ inch corrosion resisting rods, not less than eight (8) feet in length and continuous throughout, driven to a minimum depth of eight (8) feet at not less than 6 foot centers, will be considered a permanent ground.

Where a common primary and secondary grounded neutral system is installed, the grounding provisions for such systems, as covered in Rule 32.4, shall apply.

Final Version

Rule 21.8

21.8    Permanently Grounded means connected to earth in such a manner that no current which can flow in the ground wire will cause a harmful voltage to exist between the grounded conductors and facilities and adjacent exposed conducting surfaces which are in good contact with the earth, or with adjacent surfaces of the earth itself, under the most severe conditions which are liable to arise in practice.

For all circuits, other than a common primary and secondary grounded neutral distribution system of 5000 volts or less, if a resistance of less than 25 ohms is not obtained, measurement being made by any approved method, the equivalent of two ½ inch corrosion resisting rods, not less than eight (8) feet in length and continuous throughout, driven to a minimum depth of eight (8) feet at not less than 6 foot centers, will be considered a permanent ground.

Where a common primary and secondary grounded neutral system is installed, the grounding provisions for such systems, as covered in Rule 32.4, shall apply.