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    Solid PE Insulated & AP Sheathed (ALPETH) Air Core Cables to GR-421

    Application

    The cables are designed for use as subscriber distribution cables and as connection between central offices. The cables are suitable for installation in ducts, direct burial in the ground and also for aerial installation with integral suspension strand. An armoured option is offered for direct burial installations. A figure-8 self support option is offered for aerial installation.

    Standards

    • Telcordia (Bellcore) GR-421

    Construction

    Conductors
    Solid annealed bare copper, 0.4/0.5/0.63/0.9mm, as per ASTM B-3/class 1 of IEC 60228

    Insulation
    Solid medium or high density polyethylene as per ASTM D 1248/IEC 60708

    Twisted Pairs
    Insulated conductors are twisted into pairs with varying lay length to minimize crosstalk

    Cabling Element
    Twisted Pairs

    Cable Core Assembly
    Cables with up to 400 pairs are composed of 25-pair units or 12/13-pair units; cables with over 400 pairs are composed of 50 or 100-pair units. Any extra pairs form a separate unit. Units are identified by colour coded binders. Construction is per GR-421 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 bare aluminium tape (0.2mm/8mil) is applied longitudinally with overlap over the cable core to provide 100% electrical shielding coverage and ensures 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 ASTM D 1248/IEC 60708, 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

    Spare Pairs (optional)
    Spare pairs may be incorporated for large pair cables

    Continuity Wire (optional)
    One tinned copper drain wire may be longitudinally laid to ensure electrical continuity of the screen

    Optional Construction

    Armoured Cable
    0.15mm thick corrugated steel tape armour is applied with an overlap over an optional inner polye-thylene sheath. 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

    Aabbreviations

    LAP (CAP):Copolymer coated aluminium tape + PE sheath 
    LAPSP (CAPSP):LAP sheath + steel tape armour + PE sheath
    AP (ALPETH): Bare aluminium tape + PE sheath
    PAP: PE inner sheath + bare aluminium tape + PE sheath 
    PASP: PE inner sheath + bare aluminium tape + steel tape armour + PE outer sheath 
    ASP (STAPETH): Bare aluminium tape + steel tape armour + PE outer sheath
    CACSP: Copolymer coated aluminum tape + copolymer coated steel tape armour + PE outer sheath
    LAPSP: Copolymer coated aluminum tape +PE inner sheath + steel tape armour + PE outer sheath
    FIGURE 8 LAP: Copolymer coated aluminum tape + PE outer sheath + self supporting

    Electrical Properties

    Nominal Conductor Diameter

    mm

    0.4

    0.5

    0.63

    0.9

    Conductor Gauge Size

    AWG

    26

    24

    22

    19

    Maximum Average DC Resistance

    Ω/km / Ω/mile

    140/225

    87/140

    55/88.6

    27.0/43.4

    Maximum Individual DC Resistance

    Ω/km / Ω/mile

    144.2/232

    89.5/144

    56.5/91.0

    28.0/45.0

    Minimum Insulation Resistance @500V DC

    MΩ.km / MΩ.mile

    1600/1000

    1600/1000

    1600/1000

    1600/1000

    Maximum Average Resistance Unbalance

    %

    1.5

    1.5

    1.5

    1.5

    Maximum Individual Resistance Unbalance

    %

    5

    5

    5

    5

    Average Mutual Capacitance nF/km / nF/kft

    48.5-54.0 /14.8-16.5

    48.5-54.0 /14.8-16.5

    48.5-54.0 /14.8-16.5

    48.5-54.0 /14.8-16.5

    Maximum Individual Mutual Capacitance nF/km / nF/kft

    57/17.4

    57/17.4

    57/17.4

    57/17.4

    Maximum Individual Capacitance Unbalance pair-to-pair pF/km / pF/kft

    145/44

    145/44

    145/44

    145/44

    Capacitance Unbalance RMS pair-to-pair pF/km / pF/kft

    45/13.7

    45/13.7

    45/13.7

    45/13.7

    Maximum Individual Capacitance Unbalance
    pair-to-ground
    pF/km / pF/kft

    2625/800

    2625/800

    2625/800

    2625/800

    Maximum Average Capacitance Unbalance
    pair-to-ground
    pF/km / pF/kft

    574/175

    574/175

    574/175

    574/175

    Maximum Conductor Loop Resistance @20°C Ω/km / Ω/mile

    300/482

    192/309

    114/183.6

    60/96.4

    Impedance @1KHz Ω

    994

    796

    660

    445

    Impedance @100KHz Ω 147 134 125 122
    Impedance @512KHz Ω 120 118 117 116
    Impedance @1MHz Ω 117 115 114 113
    Maximum Average Attenuation @0.8KHz dB/km / dB/kft 1.64/0.5 1.30/0.39 1.04/0.32 0.74/0.22

    Maximum Average Attenuation @1KHz

    dB/km / dB/kft

    1.68/0.51

    1.35/0.41

    1.08/0.33

    0.76/0.23

    Maximum Average Attenuation @3KHz

    dB/km / dB/kft

    3.18/0.97

    2.52/0.77

    2.01/0.61

    1.42/0.43

    Maximum Average Attenuation @150KHz

    dB/km / dB/kft

    11.4/3.47

    8.3/2.53

    6.2/1.89

    4.4/1.34

    Maximum Average Attenuation @772KHz

    dB/km / dB/kft

    24.3/7.4

    19.4/5.9

    15.4/4.7

    10.8/3.3

    Maximum Average Attenuation @1000KHz

    dB/km / dB/kft

    27.1/8.25

    21.4/6.52

    17.5/5.33

    12.8/3.89

    Dielectric Strength

     

     

     

     

     

    Conductor to Conductor (3secs) V DC

    2400

    3000

    4000

    5000

    Conductor to Conductor (3secs) V DC

    10000

    10000

    10000

    10000

    Minimum EL Far-end Cross-talk-Mean Power Sum          

    @150KHz

    dB/305m / dB/kft

    61

    63

    63

    65

    @772KHz

    dB/305m / dB/kft

    47

    49

    49

    57

    @1.6MHz

    dB/305m / dB/kft

    41

    42

    43

    44

    @3.15MHz

    dB/305m / dB/kft

    35

    37

    37

    39

    @6.3MHz

    dB/305m / dB/kft

    29

    31

    31

    33

    Minimum Far-end Cross-talk-Worst Pair Power Sum          

    @150KHz

    dB/305m / dB/kft

    57

    57

    57

    59

    @772KHz

    dB/305m / dB/kft

    43

    43

    43

    45

    @1.6MHz

    dB/305m / dB/kft

    37

    37

    37

    39

    @3.15MHz

    dB/305m / dB/kft

    31

    31

    31

    33

    @6.3MHz

    dB/305m / dB/kft

    25

    25

    25

    27

    Minimum Near-end Cross-talk-Mean Power Sum          

    @150KHz

    dB/305m / dB/kft

    58

    58

    58

    58

    @772KHz

    dB/305m / dB/kft

    47

    47

    47

    47

    @1.6MHz

    dB/305m / dB/kft

    43

    43

    43

    43

    @3.15MHz

    dB/305m / dB/kft

    38

    38

    38

    38

    @6.3MHz

    dB/305m / dB/kft

    34

    34

    34

    34

    Minimum Near-end Cross-talk-Worst Pair Power Sum

             

    @150KHz

    dB/305m / dB/kft

    53

    53

    53

    53

    @772KHz

    dB/305m / dB/kft

    42

    42

    42

    42

    @1.6MHz

    dB/305m / dB/kft

    38

    38

    38

    38

    @3.15MHz

    dB/305m / dB/kft

    33

    33

    33

    33

    @6.3MHz

    dB/305m / dB/kft

    29

    29

    29

    29

    Nominal Insulation Thickness

    mm

    0.175

    0.2

    0.26

    0.3

    Nominal Insulated Conductor Diameter

    mm

    0.75

    0.9

    1.15

    1.5

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