Change List for this Rule

 

General Order 95

 

Section V

 

Detailed Construction Requirements for Supply Lines
(Class H, L and T Circuits)

 

54.8    Service Drops, 0 - 750 Volts

 

A.    Material and Size

Supply service drops of 0 - 750 volts shall be of material and size as specified in
Table 8 and Rule 49.4–C7a .

 

Note:    Resolution No. E–756 effective May 29, 1951 authorized the use of multiple conductor service drop cable with a bare neutral conductor for service drops of 0 - 750 volts provided that the attachment of such cable at the pole and building ends shall be by means of an insulator.

 

B.    Clearances above Ground, Buildings, Etc.

The vertical clearances of supply service drops above ground, buildings, etc., shall be not less than the minimum clearances specified in
Rule 37 , Table 1, Column B , with the following modifications:

 

(1)    Above Public Thoroughfares: Service drop conductors shall have a vertical clearance of not less than 18 feet above public thoroughfares, except that this clearance may grade from 18 feet at a position not more than 12 feet horizontally from the curb line to a clearance of not less than 16 feet at the curb line, provided the clearance at the centerline of any public thoroughfare shall in no case be less than 18 feet. Where there are no curbs the foregoing provisions shall apply using the outer limits of possible vehicular movement in lieu of a curb line.

 

(2)    Above Private Thoroughfares and Other Private Property:

 

a)    Industrial or Commercial Premises: Over private driveways, lanes, or other private property areas accessible to vehicles on premises used for industrial or commercial purposes, service drops shall have a vertical clearance of not less than 16 feet.

 

b)    Residential Premises: Over private driveways or lanes or other private property areas accessible to vehicles on premise used for residential purposes only, service drops shall have a vertical clearance not less than 12 feet.

 

EXCEPTION:    This clearance may be reduced for insulated services that conform with Rule 20.9-G to not less than 10 feet

 

Note:    Revised January 21, 1992 by Resolution SU-10.

 

(3)    Above Ground in Areas Accessible to Pedestrians Only:

Over areas accessible to pedestrians only service drops shall be maintained at a vertical clearance of not less than 12 feet.

 

EXCEPTION:    This clearance may be reduced for insulated services that conform with Rule 54.8–A , to not less than 8 feet 6 inches.

 

Note:    Revised January 21, 1992 by Resolution SU–10 and January 13, 2006 by Decision No. 05-01-030 

 

(4)    From Buildings and Structures: Service drops should be arranged so as not to hamper or endanger workers and firefighters while performing their duties.

 

a)    Vertical Clearances: Service drop vertical clearances shall be maintained over all portions of buildings and structures as required by Table 10 .

 

Note:    Revised October 2, 1951 by Resolution No. E–762 ; January 6, 1968 by Decision No. 73455; and January 21, 1992, by Resolution SU–10.

 

b)    Horizontal Clearances: Service drops are not required to clear buildings by any specific horizontal distance.

 

EXCEPTION:    A horizontal distance of not less than 3 feet should be maintained around fire escapes, exits, windows or doors.

 

Note:    Revised January 21, 1992 by Resolution SU–10.

 

Table 10: Minimum Allowable Clearance of Service Drops of 0 - 750 Volts from Buildings

 

Minimum Clearance from Buildings

Weather Resistant
Covered
Conductors
0 - 750 Volts

Insulated Conductors
(
Rule 20.9–G )
0 - 750 Volts

Vertical Clearances Above:

1) All portions of buildings including metallic or non–metallic cornice, decorative appendage, eaves, roof or parapet wall of the building served.

8 Feet

(a) (b)

2) Metallic or non–metallic non–walkable overhang, patio cover or other structure.

8 Feet

(a) (b)

3) Other buildings on the same premises.

8 Feet

2 Feet

4) Buildings on other premises.

8 Feet

8 Feet (c)

Horizontal & Radial Clearances:

1) From fire escapes, exits, windows and doors.

3 Feet

3 Feet

 

a)    Minimum clearance of 0.5 inches. 

 

b)    The point of attachment of the service drop for industrial and commercial premises is not to be more than 18 inches back of the front face of the building wall facing the pole line from which the service drop originates.

 

c)    Reduce to 2 feet for non–metallic roofs when roof slope exceeds 9 inches of rise per 12 inches of run (see sketch ).

 

Note:    Revised September 18, 1967 by Decision No. 72984; January 6, 1968 by Decision No. 73455; July 22, 1968 by Decision No. 74342; January 21, 1992, by Resolution SU–10; November 6, 1992 by Resolution SU–15 and January 13, 2006 by Decision No. 05-01-030 


skecth

 

(5)    Over Swimming Pools: (See Rule 54.4–A3 and Figure 54–1 ).

 

Note:    Added January 2, 1962 by Resolution No. E–1109 and Revised November 21, 1990 by Resolution SU–6.

 

C.    Clearances between Supply Service Drops and Other Conductors

The clearances of supply service drop conductors from other conductors shall be not less than the minimum clearances specified in
Rule 38 , Table 2, Column D , with the following modifications:

 

(1)    From Fire Alarm or Other Communication Line Conductors:

 

a)    Crossings in Spans: At crossings in spans, supply service drop conductors may have a clearance of less than 48 inches ( Table 2, Case 3, Column D; and Case 4, Column C ) but not less than 24 inches above any communication line conductors or below communication line conductors not supported on a messenger, provided the crossing is 6 feet or more from any pole which does not support both conductors involved in the crossing (See App. G, Figure 42 ).

 

b)    Supported on the Same Pole: Supply service drop conductors, other than those on a pole–top clearance attachment, may have a clearance of less than 48 inches (Table 2, Case 8, Column D; and Case 9, Column C ) above or below communication line conductors supported by the same pole and not on a messenger provided such clearance is 6 feet or more from any pole which does not support both conductors involved, and provided clearances at least equal to those shown in Table 11 are maintained.

 

Table 11:    Minimum Radial Clearance between Supply Service Drop Conductors and Communication Line Conductors Not on Messengers

Radial Distance of Crossing from Supporting Pole (Feet)

Minimum Radial Clearance (Inches)

From Police and Fire Alarm Conductors

From Other Communication Conductors

5 or less

6

12

10 or less, but more than 5

9

18

15 or less, but more than 10

15

24

20 or less, but more than 15

21

24

More than 20

24

24

 

Supply service drop conductors may have a clearance of less than 48 inches (as specified in Table 2, Case 8, Column D; and Case 9, Column C ) but not less than 24 inches above and laterally from communication line conductors supported on a messenger by the same pole provided such clearance is 6 feet or more from any pole which does not support both conductors. The vertical clearances of not less than 24 inches above or 48 inches below communication conductors supported on messengers are not required where the supply service drop conductors are 24 inches or more horizontally from the vertical plane of the communication messenger (see App. G, Figure 42 ).

 

(2)    On Clearance Crossarms: Supply service drops may be supported on a clearance crossarm at a vertical distance less than 48 inches (specified in Table 2, Case 8, Column D, and Case 9, Column C) but not less than 24 inches above or below either supply circuits of 0 - 750 volts or communication circuits not supported on a messenger, or above communication or supply circuits which are supported on a messenger, provided the supply service drop unprotected conductors are at least 25 inches horizontally from the centerline of the pole or are attached to suitable brackets (at least 25 inches from center line of pole) on each end of the clearance arm and carried on the underside of the clearance arm from end to end in fiber or plastic conduit or under wood protective covering as specified in Rule 54.6–C . The installation of service drops in accordance with this rule will not entail any change in the communication conductors supported on the pole (see App. G, Figure 40 ).

 

Note:    Revised June 7, 1965 by Decision No. 69071.

 

(3)    On Pole Top Extensions: Supply service drops may be carried in a clearance crossing on pole top extensions or brackets above either supply circuits of 0 - 750 volts or communications circuits, with a vertical conductor clearance less than 48 inches ( Table 2, Case 8, Column D; Case 9, Column C ) but not less than 2 feet provided the service drop conductors clear the centerline of the pole (projected) not less than 25 inches horizontally, and also provided the service drop conductors clear the outside pin position conductors of the other circuit not less than 2 feet. Where, in addition to the pole top bracket or extension, the supply service drop conductors are supported on a bracket on the end of the other line crossarm, a clearance of not less than 12 inches will be permitted at the points of crossing of line conductors in the outside pin positions. In such construction the crossarm of the extension shall be of wood. The installation of service drops in accordance with this rule will not entail any change in the communication conductors supported on the pole (see Appendix G, Figure 41 ).

 

(4)    From Communication Service Drops: The radial clearance between supply service drop conductors and communication service drop conductors may be less than 48 inches as specified in Table 2, Column C, Cases 4 and 9; Column D, Cases 3 and 8 , but shall be not less than 24 inches. Where within 15 feet of the point of attachment of either service drop on a building, this clearance may be further reduced but shall be not less than 12 inches.

 

(5)    Above Trolley Contact Conductors: Service drops may be installed above trolley contact conductors, including messenger in catenary construction, at a vertical distance of not less than 4 feet, provided the service drops clear the top of rails a vertical distance of not less than 26 feet where the railroad crossed transports standard freight cars, or not less than 23 feet where the railroad does not transport standard frights cars (see Rule 74.4–B1 ).

 

(6)    From Conductors of 750 - 7,500 Volts: Service drops may cross above or below line conductors of 750 - 7,500 volts supported on the same pole at clearances less than specified in Table 2, Case 10, Column D , provided such drops shall be not less than 2 feet vertically or 1 foot horizontally from the supply line conductors.

 

D.    Clearance from Other Poles

The clearance between service drop conductors and the centerline of any pole not supporting them shall be not less than 22 1/2 inches (
Rule 32.3 ). In case the pole involved in this clearance is within 10 feet of a pole supporting the service drop, this clearance may be less than 22 1/2 inches but shall be not less than 15 inches.

  

(1)    From Nonclimbable Street Lighting or Traffic Signal Poles or Standards: Supply service drops of 0 - 750 volts passing (unattached) nonclimbable street lighting and traffic signal poles or standards including mastarms, brackets and lighting fixtures, shall clear a radial distance of 15 inches as specified in Table 1, Case 10, Column B , except when the drops are mechanically protected from abrasion by materials specified in Rule 22.8 . Such mechanical protection shall extend not less than 15 inches in each direction along the drop from centerline of pole, standard, attaching mastarm or fixture, whether passing above, below or alongside. The drops shall be installed in such a manner so as not to interfere with light distribution from lighting fixtures and shall not hamper workmen when changing lamps or maintaining equipment.

 

Note:    Added January 8, 1980 by Decision No. 91186 and revised March 9, 1988 by Resolution E–3076.

 

E.    Clearances from Conductors on Combination Arms

In combination arm construction the following clearances are required between service drop conductors of 0 - 750 volts and the conductors of 750 - 7,500 volts:

 

(1)    36–Inch Minimum Pole Pin Position Separation: Where conductors of the two voltage classifications are supported on opposite ends of a crossarm with a minimum horizontal separation of 36 inches between pole pin positions, service drops which are run directly from such crossarm shall not cross conductors of the 750 - 7,500 volt classification on the same arm.

 

(2)    42–Inch Minimum Pole Pin Position Separation:

 

a)    Services from Line Arms: Where conductors of the two voltage classifications are supported on opposite ends of the crossarm with a minimum horizontal separation of 42 inches between pole pin positions, service drops may be run directly from the 0 - 750 volt portion of a line arm and may cross below conductors of 750 - 7,500 volts on the same arm. Under these conditions the vertical separation at the point of crossing shall be not less than 2 feet, and the point of crossing shall be not less than 6 feet radially from the centerline of pole.

 

b)    Services from Buck Arms: Where conductors of the two voltage classifications are supported on opposite ends of the buck arm with a minimum horizontal separation of 42 inches between pole pin positions and not less than 2 feet vertical separation between line arm conductor level and buck arm conductor level, service drops may be run from line buck arms or service buck arms, provided:

 

Such service drops shall clear conductors of 750 - 7,500 volts by not less than 2 feet vertically at the point of crossing;

 

Such service drops shall not pass through the climbing space specified in Rule 54.7–A3c ;

 

Such service drops shall not cross under the 750 - 7,500 volt end of the line arm within the third pin position; and;

 

Where such service drops are run from double buck arms, or from single buck arms installed on the side of the pole below the 750 - 7,500 volt portion of the related line arm, the pole–pin position on the 750 - 7,500 volt end of the line arm shall be left vacant.

 

F.    From Racks

Service drops may be run directly from low voltage racks on poles. Where multiple conductor service cable is used, the cable grip shall be attached to the neutral insulator of the rack on the pole or suitable insulation shall be used between the point of attachment on the rack or pole and the surface of the cable, except where the rack hardware is effectively grounded through the medium of a metal pole.

 

G.    Service / Clearance Poles (See Rule 22.6-F For Definition)

 

(1)    Service / Clearance Poles Shall Support Only:

 

a)    0 - 750 Volt conductors (See Rule 54.8–G2 )

 

b)    Service drops

 

c)    Associated risers and runs

 

d)    Associated guys

 

e)    Lighting and its associated equipment

 

f)    Communication facilities

 

(2)    Construction Requirements:

 

a)    All supply service drop strength requirements may be applied to 0 - 750 volt conductors (secondary) installed under this Rule.

 

b)    Span lengths shall not exceed 150 feet.

 

c)    Supply conductors (secondary) installed between service / clearance poles shall meet the 0 - 750 volt conductor clearance requirements of Rule 37 , Table 1, Column D and Rule 38 , Table 2, Column D

 

d)    Multiple service drops, risers and street lights may be served from 0 - 750 volt conductor (secondary) installed under this Rule.

 

Note:    54.8G added November 6, 1992 by Resolution SU–15