Standards
• IEC 60708
Construction
Conductors
Solid annealed bare copper, 0.4/0.5/0.6/0.63/0.8/0.9 mm as per class 1 of IEC 60228 & ASTM B-3
Insulation
Foam Skin which is a composite polyethylene insulation made of an inner cellular layer and an outer solid skin, as per IEC 60708/BS EN 50290-2-23/BS 6234/ ASTM D 1248/NFC 32-060/VDE 0207
Twisted Pairs
Insulated conductors are twisted into pairs with varying lay length to minimize crosstalk
Cabling Element
Twisted Pairs
Cable Core Assembly
Cables with 100 pairs or less are composed of 10-pair sub-units; cables with over 100 pairs are composed of 50 or 100-pair units. Any extra pairs form a separate unit. Units are identified by colour coded binders. Standard construction is per IEC 60708 given in Cable Make Up Diagram
Core Wrapping
One or more non-hygroscopic polyester tapes are helically or longitudinally laid with an overlap. These tapes furnish thermal, mechanical as well as high dielectric protection between shielding and individual conductors
Moisture Barrier
A layer of aluminium tape (0.15mm) coated with PE-copolymer on one or both sides is applied longitudinally with overlap over the cable core to provide 100% electrical shielding coverage and ensure a barrier against water vapor. In cables with more than 200 pairs, the aluminum tape may be corrugated for improved cable flexibility
Sheath
Black low density polyethylene as per BS 6234/IEC 60708/ASTM D 1248, being able to withstand exposure to sunlight, temperature variations, ground chemicals and other environmental contaminants
Ripcord
Ripcord may be provided for slitting the sheath longitudinally to facilitate its removal
Optional Construction
Armoured Cable
Steel wire armour or corrugated steel tape armour is applied over an optional inner polyethylene sheath. For steel tape version, the 0.2/0.5mm thick steel tape is coated with a copolymer and applied with an overlap. An outer polyethylene sheath is applied over the armour
Self-Support Cables
A 7-strand galvanized steel strand is used as support wire. Black polyethylene sheath covers both core and support wire in a figure-8 construction
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Outdoor Telephone Cables