Rule 21.4

21.4    Insulated means separated from other conducting surfaces by a dielectric substance, (including air-space) offering a high resistance to the passage of current.  Air space when used as insulation shall be maintained by permanently forming the conductor or by adding additional mechanical means (e.g. spreader bar).  When an object is said to be insulated, it is understood to be insulated in a suitable manner for the condition to which it is normally subjected.

Strikeout and Underline Version

Rule 21.4

21.4    Insulated means separated from other conducting surfaces by a dielectric substance, (including air-space) offering a high resistance to the passage of current.  Air space when used as insulation shall be maintained by permanently forming the conductor or by adding additional mechanical means (e.g. spreader bar).  When an object is said to be insulated, it is understood to be insulated in a suitable manner for the condition to which it is normally subjected.

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.

Final Version

Rule 21.4

21.4    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.