General Order 95
Construction Requirements for Supply Lines
(Class H, L and T Circuits)
58.1 Enclosed Equipment (Transformers, Capacitors, Regulators, etc.) (For purposes of this rule, enclosed means encased such as with cases or tanks of equipment operated at greater than 750 volts.)
A. Position on Pole
(1) Multiple Units: Where more than one unit is installed on a pole, they shall be placed on the same side of the pole. Transformers installed on metal mounting brackets shall not extend beyond the vertical plane through the centerline of the pole.
Exception: Units installed on non-climbable poles may extend beyond the vertical plane through the centerline of the pole. (See Rule 22.6-D)
Note: Revised January 15, 2015 by Decision 15-01-005.
(2) Pole Top Extensions: Equipment shall not be supported on pole top extensions.
EXCEPTION: Pole top extensions that conform with strength requirements for a whole pole (see Rule 49.1–A ) may be used to support equipment.
Unprotected Lead Wire Clearances: Unprotected vertical and lateral
leads between line conductors and equipment shall comply with Rules 54.6 and 54.4–C6 ; and with the clearances specified
in Table 1, Cases 8 and 9 ; and Table
2, Cases 15, 16 and 17
. Such lead wires may be installed in the working space but shall not be
installed in the climbing space.
The clearance specified in Table 1, Case 8, Columns D and E , need not apply to apparatus installed on poles consisting of single–pole structures or on crossarms attached thereto, provided that terminals and lead wires are not less than 6 inches from surface of pole instead of 3 inches specified in Table 1, Case 9, Columns D and E , and have as much as possible of the clearances specified in Table 1, Case 8, Columns D and E. No reduction of the clearances specified in Table 1, Case 8, Columns D and E is permitted for interconnection wiring of polyphase installations nor to any lead wire passing between pole and apparatus.
(2) Cases above Ground: Cases of equipment supported on poles or structures shall be not less than 17 feet above the ground except that in areas which are not in any way accessible to vehicles, the clearance of cases above ground may be less than 17 feet provided all cases which are less than 8 feet above ground shall be effectively grounded.
Equipment cases, hangers, and other metal parts in contact therewith shall
clear through bolts, arm braces of metal, and other hardware elements, by not
less than 1.5 inches; except that such cases and hangers shall clear crossarm
braces and crossarm through bolts by not less than 1 inch air–gap distance and
1.5 inch creepage distance.
The minimum clearance of 1.5 inches need not apply to through bolts in metallic contact with equipment cases or metal parts thereof nor to through bolts supporting heel arms, provided the portion of such through bolts extending into the climbing space is covered with non–conducting material as specified in Rule 22.8 .
(4) From Guys: Equipment cases and their hangers shall not be less than 4 inches from all portions of guys which are 6 inches or more from the surface of poles or crossarms at the guy attachments. Such cases and hangers shall not be less than 1.5 inches from all portions of guys which are within 6 inches of the surface of poles or crossarms at the guy attachment.
Equipment Cutouts or Other Equipment Disconnecting Devices
Equipment cutouts, fuses, disconnects or switches shall be located so that they are readily accessible from climbing and working spaces. Such devices or their connecting leads shall not extend into the climbing space, but may extend into the working space.
The vertical clearance between equipment cutouts, fuses, disconnects or switches and unprotected conductors of other circuits below shall not be less than the clearances required between conductors as specified in Table 2, Cases 8 to 13 .
The horizontal clearance between equipment cutouts, fuses, disconnects or switches and unprotected conductors of different phase or polarity shall not be less than the clearances specified in Table 2, Case 17 .
The provisions of this rule shall not apply to partial underground distribution systems.
D. Ungrounded Case Clearances from Line Conductors (See Table 58–2 )
E. Grounded Case Clearances from Line Conductors (See Rule 54.4–G )
Cases of equipment may be bonded together but shall not be bonded to cutouts, metal pins or deadend hardware.
(a) May be reduced to 20 feet provided such lead or bus wires are guarded by transformer platform flooring which extends not less than 1 foot horizontally outside the vertical planes of all such lead and bus wires.
(d) May be reduced to 3 inches radially from unenergized cases and hangers, provided no line conductor which is less than 12 inches horizontally from the case or hanger is less than 3 inches above the level of the top surface of the crossarm.