Change List for this Rule

 

General Order 95

 

Section VIII

 

Detailed Construction Requirements for Communication Lines
(Class C Circuits)

 

86.4    Clearances

The basic minimum clearances are specified in Tables 1 and 2 , Rules 37 and 38 respectively. Modifications are specified in the following provisions:

 

A.    Above Ground

 

(1)    Over, across or along Public Thoroughfares: Minimum clearance shall not be less than 18 feet (Table 1, Case 3, Column A ).

 

EXCEPTIONS:

 

(a)    A minimum clearance of 16 feet is permitted over an entrance to or exit from industrial or commercial premises.

 

(b)    A minimum clearance of 14 feet is permitted over an entrance to or exit from private residential premises.

 

(c)    Clearances of overhead guys along public thoroughfares, above ground which is not normally accessible to vehicles, may be less than as specified in Table 1, Column A, Cases 3 and 4 (18 feet and 15 feet respectively) but shall not be less than 8 feet.

 

Note:    Revised January 19, 1994 by Resolution SU25 and October 9, 1996 by Resolution SU40.

 

(2)    Over Private Property: Those portions of guys over private roadways or areas normally accessible to vehicles may have a clearance above ground less than 18 feet (Table 1, Case 3, Column A ) but not less than 16 feet in rural districts and not less than 14 feet in urban districts.

 

(3)    Over Swimming Pools (See Rule 84.4A5c and Figure 841 )

 

Note:    Added January 2, 1962 by Resolution No. E1109 and revised November 21, 1990 by Resolution SU6.

 

B.    Above Railways and Trolley Lines

 

(1)    Which Transport Freight Cars: The clearance specified in Table 1, Case 1, Column A (25 feet) is based upon the maximum height of standard freight cars, 15 feet 6 inches from top of rail to top of running board. This clearance shall in no case be reduced more than 5% because of temperature, wind or mechanical loading.

 

(2)    Operated by Overhead Trolley: The clearance of 26 feet specified in Table 1, Case 2, Column A is based upon a trolley pole throw of 26 feet. Guys and span wires may have clearances of less than the trolley throw distance (26 feet) above the running surfaces, top of rail or surface of street, used by trolley cars or coaches provided the guys and span wires are not less than 4 feet above the trolley contact conductors and are encased in wood boxing or moulding 7/8 inch or more in thickness for distances of at least 2 feet horizontally from the vertical plane through each trolley contact conductor.

 

C.    From Conductors

 

(1)    Crossing in Spans: Vertical clearances at points of crossing not less than as specified in Table 2, Case 1 , and radial clearances not less than as specified in Table 2, Case 18 , shall be maintained between guys or span wires and conductors supported on other poles.

 

(2)    On Colinear Lines: The radial clearances between guys on a line and conductors on a colinear line shall be not less than as specified in Table 2, Case 18 . Vertical clearances not less than as specified in Table 2, Case 1 , shall also be maintained at points of crossing between guys on a line and conductors supported on other poles of a colinear line.

 

(3)    Parallel on Same Poles: The radial clearances between guys and communication conductors which are approximately parallel and supported by the same poles may be less than as specified in Table 2, Case 18 , but shall be not less than 3 inches.

 

(4)    Passing on Same Poles: The radial clearances between guys and conductors supported by or attached to the same poles or crossarms shall be not less than as specified in Table 2, Case 19 except that the clearance between guys and communication messenger and/or cable attached directly to surface of pole may be less than the 3 inches specified in Table 2, Case 19, Column C provided: the guy is not a guy in proximity, or all parts of the guy are not less than 6 feet below 0 - 750 volt supply conductors supported on same pole, and a wood guard or equivalent is placed on the messenger and/or cable; also, a guy attached to a pole which supports supply conductors at a distance of not less than 6 feet above communication messenger and/or cable shall (1) have an insulator placed in the guy above the communication messenger and/or cable, at a distance of not less than 6 feet horizontally from the pole, or (2) have an insulator placed in the guy not less than 3 inches nor more than 6 inches above the messenger and/or cable, and a wood guard or equivalent placed on the messenger and/or cable.

 

Note:    Revised February 14, 1968 by Decision No. 73722.

 

D.    From Span Wires or Other Guys

 

(1)    Crossing in Spans: At points of crossing, vertical clearances, not less than 18 inches as specified in Table 2, Case 1, Column A , and radial clearances of not less than 12 inches, shall be maintained between guys or span wires and other guys or span wires which are not attached to the same poles.

 

(2)    Passing and Attached to Same Pole: Where a guy of a communication system and a guy of a supply system pass each other and are attached to the same pole, a separation of not less than 3 inches shall be maintained between such guys. No separation is required between such guys of communication systems, provided neither is an exposed guy (see Rule 21.5C ).

 

(3)    Approximately Parallel and Attached to Same Poles: Where two or more overhead guys are approximately parallel and attached to the same poles, either or both of which poles support supply conductors, such guys shall have a vertical separation of at least one foot between the points of attachment on the pole, or poles, which support supply conductors. In cases where this 1 foot minimum separation is not practicable other means may be employed to insure the effectiveness of guy insulators, but in no case shall the distance between any guy wire and the surface of the insulator in any other guy be less than 3 inches. This rule shall not prohibit the contact of such guys to the same shim and shall not apply to guys acting in different directions, nor to guys in which insulators are not required by any provision of Rule 86.6 .

Where two or more anchor guys are attached to the same pole carrying supply conductors and the same grounded anchorage, either directly or through the medium of a stub, they shall be separated at the pole by a vertical distance of at least one foot, provided any guy wire shall be not less than 3 inches from the surface of the insulator in any other guy. In lieu of securing this 3 inches minimum separation by means of the 1 foot minimum separation of guy attachments at the pole, it shall be afforded by separation of the grounded anchorages or by other practicable means which shall insure the minimum clearance of 3 inches. The provisions of this rule do not apply to guys which act in different directions from the pole or to guys attached to grounded metal structures or to guys which do not require insulators.

The provisions of this rule requiring separation of guys shall not be held to apply to guys attached to poles supporting only communication conductors.

 

E.    From Poles

Where guys passing poles supporting supply conductors are less than 15 inches from surface of pole and less than 8 feet below supply conductors of less than 35,500 volts supported on such pole, the guys shall be sectionalized, in addition to the normal sectionalization required by
Rule 86.6 , by means of insulators in accordance with Rule 86.6B2 as though attached to the pole or structure.

 

Note:    Revised March 29, 1966 by Decision No. 70489; August 9, 1966 by Decision No. 71094 and November 20, 1979 by Decision No. 91030.

 

F.    Above Buildings

The minimum vertical clearance of 8 feet specified for guys above buildings (
Table 1, Case 6, Column A ) may be reduced to a clearance of not less than 2 feet when the roofs slope exceeds 9 inches of rise per 12 inches of run (see sketch).

 

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Note:    Revised October 9, 1996 by Resolution SU40.