The first 150 mm 6 inch layer of backfill shall be of sand. Machine
compaction shall not be used within 150 mm 6 inches of the cable.
3.2.3.3
Other Requirements
Where direct-burial cables cross under roads or other paving exceeding 1.5
m 5 feet in width, such cables shall be installed in concrete-encased
ducts. Where direct-burial cables cross under railroad tracks, such cables
shall be installed in reinforced concrete-encased ducts. Ducts shall
extend at least 300 mm 1 foot beyond each edge of any paving and at least
1.5 m 5 feet beyond each side of any railroad tracks. Cables may be pulled
into duct from a fixed reel where suitable rollers are provided in the
trench. Where direct burial cable transitions to duct-enclosed cable,
direct-burial cables shall be centered in duct entrances, and a waterproof
nonhardening mastic compound shall be used to facilitate such centering.
If paving or railroad tracks are in place where cables are to be installed,
coated rigid steel conduits driven under the paving or railroad tracks may
be used in lieu of concrete-encased ducts. Damage to conduit coatings
shall be prevented by providing ferrous pipe jackets or by predrilling.
Where cuts are made in any paving, the paving and subbase shall be restored
to their original condition.
3.2.3.4
Cable Joints or SplicesMedium-Voltage Cable Joints or Low-Voltage
Cable Splices
Cable joints or splices in direct-burial cables are not permitted in runs
of 305 m 1000 feet or less, nor at intervals of less than 305 m 1000 feet
in longer runs, except as required for taps. Locations of cable joints or
splices in shorter intervals, where required to avoid obstructions or
damage to cables, shall be approved. Cable joints or splices in direct
burial installations shall be installed in above-ground junction boxes or
in cast metal splice boxes suitable for direct burial use. Cable joints or
splices in duct banks shall be made only in manholes, handholes, or
pullboxes.
3.2.3.5
Cable Markers
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NOTE: Coordinate with UFGS-02300 EARTHWORK, for
underground marking requirements.
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Markers shall be located [as indicated] [near the ends of cable runs, at
each cable joint or splice, at approximately every 150 m 500 feet along
cable runs, and at changes in direction of cable runs]. In addition to
markers, a 0.127 mm 5 mil, brightly colored plastic tape not less than 75
mm 3 inches in width and suitably inscribed at not more than 3 m 10 feet on
centers, or other approved dig-in warning indication, shall be placed
approximately 300 mm 12 inches below finished grade levels of trenches.
3.2.4
Insect and Rodent Damage
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NOTE: In areas where insect and rodent damage to
buried cable is a problem, the following steps
should be considered:
a.
Specify armored cable.
SECTION 16375A
Page 52
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