General Order 64-A
Section V
Detailed Construction Requirements For Supply Lines
(Class H, L and T Circuits)
58.3 Street Lighting Equipment.
A. Clearances. (See App. G, Fig. 55.)
(1) Above Ground: No part of street lighting equipment shall be less than 20 feet above thoroughfares except for lamps supported on brackets or fixtures which do not extend more than 48 inches from the face of pole or street side form curb, in which case the clearance may be reduced to 15 feet, provided the voltage does not exceed 750.
(2) Above Railways: No part of street lighting equipment shall be less than 23 feet or 26 feet, depending on the ultimate location of the contact conductors (see Rule 74.4-B) above the rails of railroads which are operated by overhead trolley contact conductors. For railroads not operated by overhead trolley contact conductors, the vertical clearance shall be not less than 25 feet except that in either case this clearance may be reduced to 20 feet for that portion of the equipment which is 8.5 feet or more from center line of tracks.
(3) From Conductors: Street lighting equipment, including the supporting rods, braces and guys, shall not be less than one foot above or below all conductors of open wire and not less than one foot above or 2 feet below all circuits carried in cables.
(4) From Poles: All exposed metal parts of lamps and all such parts of their supports, unless insulated from the parts carrying current, shall be maintained not less than 20 inches from the surface of pole structure if of wood (unless at pole tops). This rule shall not apply if the voltage of the circuit from which the lamp is supplied does not exceed 750 volts.
B.
Open Wire Drops.
Open wire drops from the line
conductor to service conductor and to street lights shall not impair the
climbing or working space, nor shall they pass between conductors of any other
circuit other than the pole conductors, nor shall they clear the conductors of
other circuits by a distance of less than 12 inches under the most severe
conditions. It is recommended that
wherever practicable the lead wires from the line conductor to the street light
be carried in conduit attached to the pole and properly protected, as specified
in Rule 54.6-A1. Where the distance
between levels is in excess of 10 feet, additional supports shall be installed equidistant
between the levels involved.
C.
Insulators In Supports.
Where a series street lamp is
supported by a span wire, a strain insulator shall be inserted in the span wire
on both sides of the lamp not more than 9 feet nor less than 6 feet from the
supporting structures, except that where supporting span wires are used as
trolleys for the purpose of drawing lamp to the pole, the strain insulator at
the service end may be located a minimum distance of 15 inches from the center
line of pole.
Where metallic ropes or chains
are used for the suspension of street lamps, said ropes or chains shall be
effectively insulated from current carrying parts of equipment and of such
length that when the lamp is in its normal position the lower end of the chain
or rope will not be less than 8 feet from the ground, or a strain insulator
shall be inserted in the free end of the rope or chain at a point not less than
7 ½ feet from the ground when the lamp is in its normal position.
In case this construction will
not permit the lamp to be lowered sufficiently for trimming purposes, a
nonmetallic rope shall be used.
D.
Lighting Units on Transformer Poles.
Where a lamp is installed above a
vertical separation of 4 feet from any portion of the transformer or switch and
the lighting unit shall be maintained.
Where a lamp is installed below a
transformer, any portion of the lighting equipment shall clear all supply
equipment a minimum distance of one foot, under the most severe conditions.
E.
Cut-Outs.
A suitable device shall be
provided by which each street lamp on series circuits of more than 750 volts
may be safely and entirely disconnected from the circuit, before the lamp is
handled, unless the lamps are worked on from the poles or from suitable
insulating stools, platforms or tower wagons.
Exempted from this provision are lamps such as incandescent lamps which
is themselves present a non-current carrying surface which may be utilized as a
handle in removing them from their support.
F.
Exceptions.
Lighting units supported on
ornamental posts and supplied from underground sources are not included herein.