Metallic fences enclosing, and other metal structures in or surrounding a substation with exposed electrical conductors and equipment shall be grounded and bonded to limit step, touch, and transfer voltages.Where metal fences are located within 5 m (16 ft) of the exposed electrical conductors or equipment, the fence shall be bonded to the grounding electrode system with wire-type bonding jumpers as follows
(1) Bonding jumpers shall be installed at each fence corner and at maximum 50 m (160 ft) intervals along the fence.
(2) Where bare overhead conductors cross the fence, bonding jumpers shall be installed on each side of the crossing.
(3) Gates shall be bonded to the gate support post, and each gate support post shall be bonded to the grounding electrode system.
(4) Any gate or other opening in the fence shall be bonded across the opening by a buried bonding jumper.
(5) The grounding grid or grounding electrode systems shall be extended to cover the swing of all gates
(6) The barbed wire strands above the fence shall be bonded to the grounding electrode system
Alternate designs performed under engineering supervision shall be permitted for grounding or bonding of metal fences.
Information Note 1: A non-conducting fence or section may provide isolation for transfer of voltage to other areas.
Information Note 2: See IEEE 80-2000, IEEE Guide for Safety In AC Substation Grounding, for design and installation of fence grounding.
