Rule 21.2

21.2    Grounded means connected to earth by a ground connection or by an unintentional conducting path.

A.    Effectively Grounded means grounded through a ground connection of sufficiently low impedance (inherently and/or intentionally obtained) that fault grounds which may occur cannot build up voltages dangerous to connected equipment.

(1)    If an impedance of less than 25 ohms is not obtained, the equivalent of a ground conductor not less than No. 6 AWG copper connected to two corrosion resisting rods, not less than 1/2 inch in diameter and 8 feet in length and continuous throughout, driven to a minimum depth of 8 feet in the earth at not less than 6 foot centers, will be considered an effective ground for the purpose of these rules.

(2)    Where a common neutral system is installed, the grounding provisions for such systems, as covered in Rule 59.4 , shall apply.

B.    Permanently Grounded refers to time, and means grounded while the equipment concerned is in place under the conditions specified in the rules.

C.    Securely Grounded means connected to earth through a metal surface in good contact with the earth (soil, rock, etc.) such as the contact of anchor rods or metal poles set directly in the ground. Metal poles set in concrete are considered as grounded but will not be considered as securely grounded.

Strikeout and Underline Version

Rule 21.2

21.2    Grounded means connected to earth by a ground connection or by an unintentional conducting path.

A.    Effectively Grounded means grounded through a ground connection of sufficiently low impedance (inherently and/or intentionally obtained) that fault grounds which may occur cannot build up voltages dangerous to connected equipment.

(1)    If an impedance of less than 25 ohms is not obtained, the equivalent of a ground conductor not less than No. 6 AWG copper connected to two corrosion resisting rods, not less than 1/2 inch in diameter and 8 feet in length and continuous throughout, driven to a minimum depth of 8 feet in the earth at not less than 6 foot centers, will be considered an effective ground for the purpose of these rules.

(2)    Where a common neutral system is installed, the grounding provisions for such systems, as covered in Rule 59.4 , shall apply.

B.    Permanently Grounded refers to time, and means grounded while the equipment concerned is in place under the conditions specified in the rules.

C.    Securely Grounded means connected to earth through a metal surface in good contact with the earth (soil, rock, etc.) such as the contact of anchor rods or metal poles set directly in the ground. Metal poles set in concrete are considered as grounded but will not be considered as securely grounded.

21.0    Districts mean areas as defined in the following:

A.    Urban Districts mean thickly settled areas (whether in cities or suburbs) or where congested traffic often occurs. Highways on which traffic is often very heavy or locations such as picnic grounds, summer resorts, etc., where people congregate seasonally, are considered as urban.

B.    Rural Districts mean all areas not urban, usually in the country but in some cases within city limits.

C.    Loading Districts mean those areas in which the specified loadings of Rule 43 apply and are known as “Heavy” and “Light” loading districts.

Final Version

Rule 21.2

21.0    Districts mean areas as defined in the following:

A.    Urban Districts mean thickly settled areas (whether in cities or suburbs) or where congested traffic often occurs. Highways on which traffic is often very heavy or locations such as picnic grounds, summer resorts, etc., where people congregate seasonally, are considered as urban.

B.    Rural Districts mean all areas not urban, usually in the country but in some cases within city limits.

C.    Loading Districts mean those areas in which the specified loadings of Rule 43 apply and are known as “Heavy” and “Light” loading districts.