Original General Order 95

Section V

Detailed Construction Requirements for Supply Lines

(Class H, L and T Circuits)

54.7    Climbing and Working Space

A.    Climbing Space

Climbing space, measured from centerline of pole, shall be provided on one side or in one quadrant of all poles or structures, with dimensions as specified in Rules 54.7-A1, 54.7-A2 and 54.7-A3.

The climbing space shall be maintained in the same position for a distance of not less than 4 feet vertically both above and below each conductor level through which it passes. Compliance with this requirement necessitates that the position of the climbing space shall not be changed through conductor levels which are less than 4 feet apart.  Where the vertical distance between consecutive conductor levels is 4 feet or more, and less than 8 feet the position of the climbing space through such consecutive levels may be shifted not more than one-quarter of the distance around the pole.  Where a conductor is installed at the top of a pole under the provisions of Rule 54.4-D8, the climbing space shall extend up to the level of such pole-top conductor but need not be provided through and above such level.

Allowable obstruction of these climbing spaces, where necessary, are specified in Rule 54.7-A4

(1)    Dimensions Where Crossarms are Not Involved:

Climbing space through the levels of conductors deadended on poles in vertical configuration shall be a square of the horizontal dimensions tabulated below; and one side of such climbing space shall be bounded by the vertical plane of the dead-ended conductors with the centerline of pole bisecting such side (see App. G, Fig, 15)

For climbing space dimensions for low voltage rack construction see Rule 54.9-F.

(2)    Dimensions Where Line Arms Only Are Involved:

The climbing space through levels where line arms without related buck arms are present on poles or structures shall be on one side or face of the pole, with the center line of pole approximately midway on one side of the climbing space (see App. G Fig. 16), and shall have the following dimensions:

For conductors of 0-7500 volts, the climbing space shall be not less than 30 inches square except that for combination arm construction the climbing space shall be not less than 36 inches square.  (see Rule 54.8-E for additional requirements where service drops from combination line arms are involved.)

For conductors of 750-46,000 volts the climbing space shall not be less than 36 inches square.

For conductors of more than 46,000 volts the climbing space shall be a square the sides of which shall be not less than 36 inches plus ½ inch per kV in excess of 46 kV.

The above dimensions may be reduced not more than 2 percent because of line angles.

(3)    Dimensions Where Buck Arms Are Involved: The climbing space where line arms and related buck arms are involved on pole or structures shall be in a quadrant and shall have at least the dimensions, determined according to voltage classification as given below.  These dimensions are based on the minimum clearance from center line of pole (Table 1, Case 8) and minimum pin spacings (Table 2, Case 15) for the voltages involved, with the pin position numbered outward from the pole on the climbing side.

Where metal back braces are used they shall be considered as one of the arms of double arm construction.

a)    For Conductors of 0-750 Volts: Where single line arm and buck arm construction is involved and the climbing space is left open opposite the single arm, the No. 1 pin Position shall be left vacant in the single arm.  (See App G, Fig 18.)

Where double line arm and double buck arm construction is involved , the No. 1 pin position shall be left vacant in each arm.  (see App. G, Fig. 19)

b)     For conductors of More than 750 Volts: Where single arm and single buck arm construction is involved and the climbing space is left open on the opposite side of the pole from the arms, the No. 1 pin position shall be left vacant in both line arm and buck arm (see App. G, Fig. 20).  As an alternative, where the conductors are of 750-7500 volts, the No. 1 and No. 2 pin positions in one arm may be left vacant provided the arms involved are in top positions on the pole.

Where double line arm and single buck arm, or vice versa, construction is involved and the climbing space is left open on the side of the pole opposite the single arm, the No. 1 pin position shall be left vacant in both line arm and buck arm (see App. G, Fig. 21).  AS an alternative, where the conductors are of 750-7500 volts the No. 1 and No. 2 pin positions may be left vacant in the single arm provided the arm involved are in top positions on the pole.

Where double line arm and double buck arm construction is involved the No. 1 pin position shall be left vacant in one double arm and the No. 1 and No. 2 pin positions shall be left vacant in the other double arm.  (See App. G, Fig 22.)

c)    For Combination Arm Construction with Line Arm and Line Buck Arm or Service Buck Arm:  (See Rule 54.8-E for additional requirements where service drops are involved.)

Where the vertical separation between conductor levels on line and buck arms is not less than 4 feet and the climbing space is in a 0-750 volt quadrant, the climbing space dimensions shall be not less than those prescribed in Rule 54.7-A3a for 0-750 volt conductors provided that the required vacant pin conductors provided that the required vacant pin spaces shall be in addition to the 36-inch horizontal conductor separation required in Rule 54.4-C2b.  (See App. G, Figs 23, 24 and 25.)

Where the vertical separation between conductor levels on line and buck arms is not less than 4 feet and the climbing space is in a 750-7500 volt conductors provided that the required vacant volt conductors provided that the required vacant pin spaces shall be in addition to the 36-inch horizontal conductor separation required in Rule 54.4-C2b.  (See App. G, Figs 26, 27 and 28.)

Where the vertical separation between conductor levels the vertical separation between conductor levels on line and buck arms is less than 4 feet such separation shall not be less than 2 feet and the climbing space dimensions, in any quadrant, shall be not less than those prescribed in Rule 54.7-A3b for 750-7500 volt conductors, provided that the required vacant pin spaces shall be in addition to the 42-inch horizontal conductor separation required in Rule 54.4-C2b.  (See App. G Figs 29, 30 and 31.)

d)    Alternatives: Where a single line arm or single buck arm is involved and it is impractical to locate the climbing space in the quadrant on the opposite side of the pole from the single arm, it may be located in another quadrant provided that any single arm or arms within the climbing space shall be treated as a double arm.

In applying the pin position spacings as prescribed in Rule 54.7 not less than the minimum spacings of Table 2, Case 15 shall be used.  In the event the crossarms used are not bored for the minimum spacings, a spacing of conductors to give equivalent dimensions will be considered as meeting the requirements.

(4)    Allowable Climbing Space Obstructions: Crossarms and their supporting members are allowed in climbing spaces provided that, where buck arms are involved, any arms within climbing spaces are treated as double arms.

Suitably protected vertical conductors attached tot eh surfaces of poles, and guys, (except those guys contacting metal pins or dead-end hardware as specified in Rule 52.7-D) are allowed in climbing spaces provided that not more than one guy and one vertical riser, run, or ground wire are installed in any 4-foot vertical section of climbing space.  The terminals or terminal fittings of risers or runs shall not be installed within climbing spaces.

Pin-type insulators which support line conductors of 20,000 volts or less may extend not more than one-half of their diameter into the climbing space.  Dead-end or strain type insulators which support line conductors of 0-750 volts may extend not more than one-half of their diameter into the climbing space.

Modifications of these requirements for rack construction are specified in Rule 54.9-F.

B.    Working Space

Working Spaces, unobstructed by conductors or other equipment except as provided in Rule 54.7-B2, of the dimensions as specified in Rule 54.7-B1, shall be provided dimensions as specified in Rule 54.7-B1, Shall be provided between conductor levels on all poles in such positions that the working levels on all poles and in such positions that the working space include the climbing space.

(1)    Dimensions of Working Space:  Dimensions of Working Space:  The vertical dimensions of the working space above and below any conductor level shall be equal to the vertical clearances between conductors specified in Table 2, Cases 8 to 14 inclusive, for the voltages involved.

The width of the working space where crossarms are involved shall be the distance between outside pin positions of the crossarms involved.  The depth of the working space where crossarms are involved shall be equal to the width of the climbing space and shall be measured perpendicularly from the face of crossarm.

(2)    Allowable Working Space Obstructions: Taps from conductors on line arms to conductors on related buck arms may pass through the working space between the levels of conductors on related line and buck arm.

Service drops of 0-750 volts may pass through the working space of conductors and may pass through working space of 750-7500 volt conductors provided not less than the clearance between service drop and line conductors specified in Rule 54.8-C6 are maintained.

Cutouts and their leads may be installed in the working space (but not the climbing space).

Switches and their leads may extend into the working space (but not the working space).

Lead wires to transformers or capacitors may pass through the working space adjacent to the line conductors to which such leads are attached.

Terminal fittings of risers and runs, and their taps, may extend into the working space provided these fittings are the only obstruction of the working space at their level on the same side of the climbing space.