Original General Order
Detailed Construction Requirements for Supply Lines
(Class H, L
and T Circuits)
A. Protection Against Corrosion (see Rule 49.8)
B. Metal Braces
(1) For Wood Crossarms: Metal crossarm braces on wood crossarms shall be not less than 1 ½ inches from lead wires, ground wires and bond wires (except as provided in Rule 53.4), metal pins and other insulator hardware, switch and cutout hardware, conduits and fittings of riser cables and cable runs, and metal braces which extend to a crossarm at another conductor level; except that on wood crossarms supporting conductors of only one circuit of more than 7500 volts, metal crossarm braces may contact bond wires, metal pins and other insulator hardware where such contact is intentionally and securely made the lower extremity of such metal braces is not less than 3 feet above the next conductor level below such braces.
(2) For Metal Crossarms: The lower extremities of metal crossarm braces attached to metal crossarms on wood poles shall be not less than 3 feet above the next conductor level below such braces. See rule 52.5 for the grounding metal arms.
C. Separation from Bond Wires and Ground Wires
Bond wires and ground wires shall have a clearance of not less than 1 ½ inches from metal pins, bolts, and other hardware on wood crossarms except where the hardware is intended to be connected to the bond or ground wires, and in being so connected does not violate other rules of this Order, in which case suitable electrical contact shall be made.
D. Separation from Metal Pins and Dead-end Hardware
Through bolts, metal signs, conduits, metal braces, mounting bolts and hardware for cutouts or other apparatus, metal street light fixtures, metal pole top extensions and metal arm extensions supported by or attached to the surface of wood poles and wood crossarms shall have a clearance of not less than 1 ½ inches from metal pins and dead-end hardware. Guys and space bolts shall have a clearance of not less than 1 ½ inches from metal pins and dead-end hardware unless contact is intended, in which case a positive electrical contact shall be made. Any guy contacting or connected to a metal pin or part of dead-end hardware shall not be placed in the climbing space.
E. Metal Back Braces
The use of metal back braces is not recommended. (see Rule 54.7-A3 for climbing space requirements.)
(1) Circuits of 0-7500 Volts: On Wood crossarms, wood poles, or wood structures, hardware which is less than 3 feet above or 6 feet below unprotected conductors of 0-7500 volts shall be nongrounded. Excepted from the requirements of this rule are the following:
Hardware of riser terminals treated as specified in Rule 54.6-F;
Hardware associated with grounded cables and messengers supported on crossarms with vertical clearances and pole clearances as specified in Tables 1 and 2 for such cables and messengers; and
Hardware associated with guarded cables and messengers which are treated as specified in Rule 57.4-F.
Circuits of More Than 7500 Volts:
Hardware of circuits of more than 7500 volts shall be securely and permanently
grounded where such hardware can act as a bond between metal parts of the
insulating supports of an energized conductor and of a de-energized portion of
the same conductor or of the de-energized portion of another conductor where
work is to be performed on the de-energized conductor. Such hardware includes the bases of
air-break switches and the tanks of oil switches. Bond wires are excepted from this requirement, and are not
required to be grounded.
The permanent grounding specified in this rule will not be required provided the regular written operating (safety) rules of the utility concerned require that:
Conductors of Circuits exceeding 7500 volts which are de-energized for work thereon shall be securely grounded during all periods of such work, and
When work is to be performed at the location of hardware described in this rule, such hardware shall be temporarily and securely grounded and securely connected to any de-energized conductors involved during all work at the location, or in lieu of temporary grounding such hardware shall be proven by test to nonenergized immediately preceding each period of work at that location.
(3) Transformer Cases and Hardware: See Rule 58.3-C3.