plastic wedges or noncorrosive metal clips placed every 610 or 915 mm 2 or
3 feet or as often as necessary to hold the wire down. Where wires cross
existing joints, encase wires in a 305 mm 12 inchlength of flexible tubing
of polyethylene material conforming to ASTM D 1248, Type II or Type III, to
break the bond between the wires and the sealing material. Provide tubing
centered on the joint and of sufficient size to accommodate the wires to
allow for movement of the wires as the joint opens and closes. Wrap ends
of tubing with tape to prevent entrance of sealing materials. Pack the
adjacent joint area temporarily with roving material, such as hemp, jute,
cotton or flax, to prevent sealing material from flowing into the open
joint. Carefully mix and apply sealing materials in accordance with the
manufacturer's instructions and at the recommended temperature. Remove
surplus or spilled material.
3.11
SPLICES FOR AIRFIELD LIGHTING CABLE
3.11.1
Connectors
Use kit type connectors to splice 5 kV single-conductor series lighting
cables. During installation and prior to covering with earth, keep mating
surfaces of connectors covered until connected and clean when plugged
together. At joint where connectors come together, install heat shrinkable
tubing with waterproof sealant.[ Alternately, the Contractor may provide
two half lapped layers of tape over the entire joint.] Joint shall prevent
entrapment of air which might subsequently loosen the joint.
3.11.2
Splicing Fixtures to the Wires in Pavement Saw Kerfs
Make splices with preinsulated watertight connector sleeves crimped with a
tool that requires a complete crimp before tool can be removed.
3.12
GROUNDING SYSTEMS
3.12.1
Counterpoise Installation
Lay counterpoise wire for entire length of circuits supplying airfield
lighting. Provide wire in one piece, except where distance exceeds the
length usually supplied, and install on top of the envelope of
concrete-encased duct and approximately 150 mm 6 inches above direct burial
cables and duct lines. Where trenches or duct lines intersect,
electrically interconnect counterpoise wires by exothermic welding.
Connect counterpoise wires together and to existing counterpoise wires.
Connect counterpoise to earth ground at every [600][_____] meter
[2,000][_____] feet of cable run, at lighting vault, and at feeder
connection to light circuit by means of ground rods as specified.
3.12.2
Fixture Grounding
Ground each fixture or group of adjacent fixtures to the counterpoise
system. Connect fixtures, steel light bases or grounding bushings on steel
conduits to the counterpoise system by a No. 6 AWG bare-stranded copper
wire. Semiflush (pancake) fixtures for direct mounting in pavement may not
be grounded. Connect copper wire to the counterpoise by exothermic weld.
3.13
MARKING AND LIGHTING OF AIRWAY OBSTRUCTIONS
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NOTE: If Section 09900, "Paints and Coatings" is
included, painting requirements should be
SECTION 16522N
Page 36
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