Original General Order 95
Section
VIII
Detailed Construction Requirements for
Communication Lines
(Class C Circuits)
84.8 Service Drops
A. Material And Size
Communication service drops shall be of material and size as specified in Table 8 and Rule 49.4-C7b with a covering at least equivalent to standard double-braid weatherproofing.
B. Attached To Surface Of Pole
(1) Service Drops From Open Wire Lines: Where open wire communication line conductors are supported on crossarms, service drop attachments (by means of hooks, knobs or brackets) on the surface of pole shall be not less than 6 feet below or 4 feet above the level of the nearest unprotected supply conductor supported. on the same pole.
(2) Service Drops From Cabled Lines:
a) Cable Supported on Crossarm: Service drops attached to crossarms supporting cables shall be not less than 15 inches from center line of pole as required by Table 1, Case 8, Column B.
b) Cable Without Guard Arm, Supported on Surface of Pole: Where the cable is supported on the surface of pole with messenger and cable 6 feet or more below the level of the nearest unprotected supply conductor, service drops may be attached to opposite sides of poles but not more than two sides (there being four sides). Such service drop attachments shall be not f less than 6 feet below the level of any supply conductor of more than 750 volts and shall be not less than 5 feet vertically below the level of any unprotected supply conductor of 0-750 volts. Where drive hooks are used, they shall occupy pole surface areas not more than 8 inches in vertical extent and 1 inch in width, and not more than four hooks shall be placed in each of these areas.
c) Cable With Guard Arm, Supported on Surface of Pole: Where the cable is supported on the surface of pole at a minimum of 4 feet below the nearest unprotected supply conductor supported on the same pole, and is below a guard arm, service drop attachments may be attached to the face, back and bottom of the guard arm, provided such attachments are not less than 15 inches from center line of pole, the drop wires are below the top surface of the guard arm and the lateral run of the drop wires is installed in accordance with the provisions of Rule 84.6-C.
C. Clearances Above Ground And Buildings
The vertical clearances of communication service drops 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 center line 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 Or Private Property:
a) Industrial and Commercial Premises: Over private driveways or lanes, or over private property accessible to vehicles, service drops shall have a vertical clearance of not less than 16 feet.
b) Residential Premises: Over residential driveways or lanes, or over residential property accessible to vehicles, service drops shall have a vertical clearance of not less than 12 feet. If the building served does not permit an attachment which will provide this 12-foot clearance without the installation of a structure on the building the clearance shall be as great as possible but in no case less than 10 feet.
(3) Above Ground In Areas Accessible To Pedestrians Only:
a) Industrial and Commercial Premises: Over areas accessible to pedestrians only, service drops shall have a vertical clearance of not less than 12 feet.
b) Residential Premises: Over areas accessible to pedestrians only, service drops shall be maintained at a vertical clearance of not less than 10 feet. If the building served does not permit an attachment which will provide this 10-foot clearance without the installation of a structure on the building, the clearance shall be as great as possible but in no case less than 8 feet 6 inches.
c) Above Ground on Fenced Railway Rights-of-Way: Service drops to railway signal devices shall be maintained at clearances as specified in Rule 84.4-A4. Service drops which are entirely on affected railway rights-of-way in areas accessible to pedestrians only may have clearances above ground less than as specified in Table 1, Column B, Case 5 (10 feet), but not less than 7 feet.
(4) From Buildings And Structures: Service drops shall be so arranged as to hamper and endanger firemen and workmen as little as possible in the performance of their duties.
Service drops are not required to clear buildings any specified horizontal distance but shall be so installed that they do not interfere with the free use of fire escapes, exits, windows, doors and other points at which ingress or egress might be expected.
Service drops of less than 160 volts and 50 watts are not required to clear the roofs of buildings on the premises served any specified vertical distance. The vertical clearance above buildings on premises other than the one being served shall be not less than 8 feet, except that a reduction to not less than 2 feet is permitted for service drops of less than 160 volts and 50 watts under the following conditions:
Over roofs of 3/8 pitch (37 degrees from the horizontal) or greater;
Over roofs where the conductor do not overhang the building by more than 6 feet.
Service drops of other communication lines (greater than 160 volts and 50 watts) shall have vertical clearances above buildings as specified for supply service drops in Table 10 (Rule 54.8-B4b).
D. Clearances Between Conductors
The clearances of communication service drop conductors from other conductors shall be not less than the minimum clearances specified in Rule 38, Table 2, Column C, with the following modifications:
(1) Above Or Below Supply Line Conductors: (See Rule 32.2-F.)
a) Crossings in Spans: Service drops which cross below supply line conductors of 0-750 volts, or above supply line cables where treated as in Rule 57.8, may have a vertical clearance less than as specified in Table 2, Case 4; Column C (48 inches), from such supply conductors, but not less than 24 inch; provided the crossing is 6 feet or more from any pole which sup- ports any conductor involved in the crossing but which does not support both conductors involved in the crossing.
b) Supported on the Same Pole: Service drops which are supported on a pole which also supports supply conductors and which are not on a pole-top clearance attachment may have a vertical clearance less than as specified in Table 2, Case 9, Column C (48 inch), above or below supply line conductors provided not less than the clearance shown in Table 15 are maintained :
TABLE 15 Minimum Radial Clearance Between Communication Service Drops and Line Conductors |
||
Radial distance of crossing from supporting pole (feet) |
Minimum radial clearance (inches) |
|
From police and fire alarm line conductors |
From supply line 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 |
(2) On Clearance Crossarms: Communication service drops may be supported on a clearance crossarm at a vertical distance less than as specified in Table 2, Case 9, Column C (48 inches), but not less than 24 inches above or below supply circuits of 0-750 volts, or above supply cables when treated as in Rule 57.8, provided the communication service drop conductors are at least 25 inches horizontally from the center line of pole or are attached to suitable brackets on each end of the clearance arm and carried on the underside of the clearance arm from end to end in fiber conduit or under wood protective covering.
Service drops installed in accordance with this rule will not entail any change in the supply conductors supported on the pole.
(3) On Pole-Top Extensions: Communication service drops may be carried in a clearance crossing on pole-top extensions or brackets above supply conductors of 0-750 volts with a minimum vertical conductor separation of 24 inches, provided the service drop conductors clear the center line of pole (projected) not less than 25 inches horizontally, and further provided the service drop conductors clear the outside pin position conductors of the other circuit not less than 24 inches. Where, in addition to the pole-top extension or bracket, the communication service drops are supported on a bracket on the end of the 0-750 volt supply line crossarm, a minimum radial clearance of 12 inches will be permitted at the point of crossing of the outside pin position conductor. In such construction the crossarm of the extension shall be of wood.
Service drops installed in accordance with this rule will not entail any change in the supply conductors supported on the pole.
(4) Above Or Below Supply Service Drops: The radial clearance between communication service drop conductors and supply 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 cross above trolley contact conductors, including messenger in catenary construction, at a vertical distance of not less than 4 feet, provided they clear the top of rails a vertical distance of 26 feet where the railway crossed transports standard freight cars or 23 feet where the railway does not transport freight cars. See also Rule 32.2-F.
E. Clearance From Other Poles
Service drops shall clear the center line of any pole by which they are not supported by not less than 22 ½ inches, except where such pole is less than 10 feet from the pole which supports the service drops. Where these two poles are less than 10 feet apart this clearance may be less than 22 ½ inches but shall be not less than 15 inches.