Telephone Cables
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Ordering Information

 Cellular PE Insulated & PE Sheathed Jelly Filled Cables to CW1236

Application

The cables are fully filled with petroleum jelly, being designed for use in access or trunk networks, from telephone exchange to subscriber area. The cables are suitable for installation in ducts and direct burial in the ground.

Standards

CW1236

Construction

CW1236

CW1236

Conductors

Solid annealed bare copper 0.32/0.4/0.5/0.63/0.9mm as per class 1 of BS 6360/IEC 60228

Insulation

Cellular polyethylene as per BS 6234/BS EN 50290-2-23/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 100 pairs are composed of 25-pair units or 12/13-pair units; cables with over 100 pairs are composed of 25, 50 or 100-pair units cabled together. Any extra pairs form a separate unit. Units are identified by colour coded binders. Standard construction is per CW 1236 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(optional)

An optional 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 ensures a barrier against water vapor

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 BS 6234/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 200 and larger 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 is applied over an optional inner polyethylene sheath. For steel tape version, the 0.15mm thick steel tape is coated with a copolymer and applied with an overlap. An outer polyethylene sheath is applied over the armour

CW1236

CW1236

Electrical Properties

Nominal Conductor Diameter mm 0.32 0.4 0.5 0.63 0.9
Conductor Gauge Size AWG 28 26 24 22 19
Conductor Size mm2 0.08 0.126 0.196 0.312 0.636
Maximum Average Conductor Resistance @20°C Ω/km 223 143 91 58 28
Minimum Insulation Resistance @500V DC MΩ.km 1500 1500 1500 1500 1500
Maximum Average Mutual Capacitance @800Hz* nF/km 56 56 56 56 59
Maximum Individual Mutual Capacitance @800Hz (for 99% cases) nF/km 64 64 64 64 65
Maximum Individual Capacitance Unbalance @800Hz pair-to-pair
(for 99% cases)
pF/500m 275 275 275 275 275
Maximum Conductor Loop Resistance @20°C Ω/km 470 300 192 114 60
Impedance @1KHz 1000 994 796 660 445
Impedance @100KHz 156 147 134 125 122
Impedance @512KHz 122 120 118 117 116
Impedance @1MHz 120 117 115 114 113
Maximum Average Attenuation @0.8KHz dB/km 1.76 1.64 1.30 1.04 0.74
Maximum Average Attenuation @1KHz dB/km 1.8 1.68 1.35 1.08 0.76
Maximum Average Attenuation @3KHz dB/km 3.4 3.18 2.52 2.01 1.42
Maximum Average Attenuation @150KHz dB/km 16.8 11.4 8.3 6.2 4.4
Maximum Average Attenuation @772KHz dB/km 29.5 24.3 19.4 15.4 10.8
Maximum Average Attenuation @1000KHz dB/km 33.5 27.1 21.4 17.5 12.8
Dielectric Strength Conductor to Conductor (3secs) V DC 500 500 500 500 500
Nominal Insulation Thickness mm 0.145 0.175 0.20 0.26 0.30
Nominal Insulated Conductor Diameter mm 0.61 0.75 0.90 1.15 1.50

*Mutual capacitance values for 0.63mm & 0.9mm may be increased by 3% for cables with a nominal number of pairs less than 400.

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 CW 1236 given in Colour Code Chart

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