Foam Skin Insulated & AP Sheathed (ALPETH) Jelly Filled Cables to GR-421

Applications

The cables are designed for use in access or trunk networks, from telephone exchange to subscriber area. The cables are suitable for installation in ducts, direct burial in the ground and also for aerial installation with integral suspension strand.Jelly filled option is for subscriber’s cables installed underground or along the edge of pavement. An armoured option is offered for direct burial installations where additional mechanical or rodent protection is required. A figure-8 self support option is offered for aerial installation.

Standards

  • Telcordia (Bellcore) GR-421

Construction

Telephone Cable - GR-421 GR-421 - Telephone Cables
Conductors Solid annealed bare copper, 0.4/0.5/0.63/0.9mm as per ASTM B-3/class 1 of IEC 60028.
Insulation Foam Skin which is a composite polyethylene insulation made of an inner cellular layer and an outer solid skin 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. Standard construction is per GR-421 given in Cable Make Up Diagram.
Core Wrapping(optional) 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.
Filling The cable core interstices are filled with petroleum jelly to avoid longitudinal water penetration within the cable.The water resistant filling compound is applied to the air space between non-hygroscopic tape and shield, shield and sheath within the cable core.
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(optional) 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 Steel wire armour or corrugated steel tape armour applied over an optional inner polyethylene sheath.For steel tape version, the 0.15mm/6mil 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.

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 Screen (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

 

Telephone Cable - GR-421 GR-421 - Telephone Cables

Mechanical and thermal properties

Temperature range during operation (fixed state) : -30°C – +70°C

Temperature range during installation (mobile state) : -20°C – +50°C

Minimum bending radius : 10 x Overall Diameter (unarmoured cables) ; 15 x Overall Diameter (armoured cables)

Colour code

Standard colour code is per GR-421 given in Colour Code Chart.

Dimensions and weight

Foam Skin Insulated & AP Sheathed (ALPETH) Jelly Filled Cables to GR-421

Cable Code Number of Pairs Nominal Sheath Thickness Nominal Overall Diameter Nominal Weight
mm/inch mm/inch kg/km/lbs/kft
0.4mm Conductor, 0.75mm Insulated Wire
TP421-02YSF(A)2Y-20P04 20 1.8/0.071 12.5/0.492 125/84
TP421-02YSF(A)2Y-25P04 25 1.8/0.071 13.5/0.531 150/101
TP421-02YSF(A)2Y-30P04 30 1.8/0.071 14.0/0.551 200/134
TP421-02YSF(A)2Y-50P04 50 1.8/0.071 16.5/0.650 280/188
TP421-02YSF(A)2Y-100P04 100 1.8/0.071 21.0/0.827 450/302
TP421-02YSF(A)2Y-200P04 200 1.9/0.075 27.0/1.06 840/564
TP421-02YSF(A)2Y-300P04 300 2.0/0.079 32.0/1.26 1205/810
TP421-02YSF(A)2Y-400P04 400 2.0/0.079 35.5/1.40 1670/1122
TP421-02YSF(A)2Y-600P04 600 2.2/0.087 42.0/1.65 2430/1633
TP421-02YSF(A)2Y-800P04 800 2.3/0.091 48.0/1.89 3155/2120
TP421-02YSF(A)2Y-900P04 900 2.3/0.091 50.5/1.99 3480/2338
TP421-02YSF(A)2Y-1000P04 1000 2.4/0.094 53.0/2.09 3930/2641
TP421-02YSF(A)2Y-1200P04 1200 2.6/0.102 57.0/2.24 4870/3272
TP421-02YSF(A)2Y-1500P04 1500 2.7/0.106 63.5/2.50 5830/3918
TP421-02YSF(A)2Y-1600P04 1600 2.7/0.106 65.5/2.58 6285/4223
TP421-02YSF(A)2Y-1800P04 1800 2.8/0.110 69.0/2.72 7000/4704
TP421-02YSF(A)2Y-2000P04 2000 2.9/0.114 72.0/2.83 7660/5147
TP421-02YSF(A)2Y-2100P04 2100 2.9/0.114 74.0/2.91 8025/5393
TP421-02YSF(A)2Y-2400P04 2400 3.0/0.118 79.0/3.11 9025/6065
0.5mm Conductor, 0.9mm Insulated Wire
TP421-02YSF(A)2Y-200P05 200 1.7/0.067 31.0/1.22 1245/837
TP421-02YSF(A)2Y-300P05 300 1.7/0.067 38.0/1.50 1845/1240
TP421-02YSF(A)2Y-400P05 400 1.8/0.071 43.0/1.69 2490/1673
TP421-02YSF(A)2Y-600P05 600 1.8/0.071 50.0/1.97 3650/2453
TP421-02YSF(A)2Y-800P05 800 1.8/0.071 56.5/2.22 4810/3232
TP421-02YSF(A)2Y-900P05 900 1.9/0.075 59.0/2.32 5300/3561
TP421-02YSF(A)2Y-1200P05 1200 1.9/0.075 69.0/2.72 7210/4845
TP421-02YSF(A)2Y-1600P05 1600 2.0/0.079 77.0/3.03 9280/6236
0.63mm Conductor, 1.15mm Insulated Wire
TP421-02YSF(A)2Y-10P063 10 1.2/0.047 13.5/0.531 160/108
TP421-02YSF(A)2Y-20P063 20 1.2/0.047 16.5/0.650 260/175
TP421-02YSF(A)2Y-30P063 30 1.2/0.047 19.0/0.748 360/242
TP421-02YSF(A)2Y-200P063 200 1.2/0.047 40.5/1.59 2025/1361
TP421-02YSF(A)2Y-300P063 300 1.4/0.055 48.0/1.89 3025/2033
TP421-02YSF(A)2Y-400P063 400 1.5/0.059 55.0/2.17 4025/2705
TP421-02YSF(A)2Y-600P063 600 1.6/0.063 66.0/2.60 5925/3981
TP421-02YSF(A)2Y-900P063 900 1.6/0.063 79.0/3.11 8800/5913
TP421-02YSF(A)2Y-1200P063 1200 1.8/0.071 90.0/3.54 11400/7660
0.9mm Conductor, 1.5mm Insulated Wire
TP421-02YSF(A)2Y-25P09 25 1.2/0.047 19.8/0.78 528/355
TP421-02YSF(A)2Y-50P09 50 1.2/0.047 26.2/1.03 975/655
TP421-02YSF(A)2Y-100P09 100 1.2/0.047 34.8/1.37 1823/1225
TP421-02YSF(A)2Y-200P09 200 1.2/0.047 48.8/1.92 3578/2404
TP421-02YSF(A)2Y-300P09 300 1.4/0.055 58.4/2.30 5259/3534
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