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Telephone Cables |  |
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Foam Skin Insulated & LAP Sheathed Jelly Filled Cables to IEC60708
Application
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. A figure-8 self support option is offered
for aerial installation.
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
TwistedPairs
Insulated conductors are twisted into pairs with varying lay length to minimize crosstalk
CablingElement
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
Filling (optional)
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/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
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 0.2/0.5mm 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
Electrical Properties
| Nominal Conductor Diameter | mm | 0.4 | 0.5 | 0.6 | 0.63 | 0.8 | 0.9 |
|---|---|---|---|---|---|---|---|
| Conductor Gauge Size | AWG | 26 | 24 | - | 22 | 20 | 19 |
| Conductor Size | mm2 | 0.126 | 0.196 | 0.283 | 0.312 | 0.5 | 0.636 |
| Maximum Average Conductor Resistance @20°C | Ω/km | 143 | 91 | 63 | 58 | 34.6 | 28 |
| Minimum Insulation Resistance @500V DC | MΩ.km | 5000 | 5000 | 5000 | 5000 | 5000 | 5000 |
| Maximum Average Mutual Capacitance @800Hz | nF/km | 53 | 53 | 56 | 56 | 59 | 59 |
| Maximum Individual Mutual Capacitance @800Hz (for 99% cases) |
nF/km | 60 | 60 | 60 | 60 | 64 | 64 |
| Maximum Individual Capacitance Unbalance @800Hz pair-to-pair |
pF/500m | 250 | 250 | 250 | 250 | 160 | 160 |
| Maximum Individual Capacitance Unbalance @800Hz pair-to-pair ( for 95% cases) |
pF/500m | 150 | 150 | 150 | 150 | 100 | 100 |
| Maximum Individual Capacitance Unbalance @800Hz pair-to-ground |
pF/500m | 1700 | 1700 | 1700 | 1700 | 1700 | 1700 |
| Maximum Individual Capacitance Unbalance @800Hz pair-to-ground ( for 95% cases) |
pF/500m | 1000 | 1000 | 1000 | 1000 | 1000 | 1000 |
| Maximum Conductor Loop Resistance @20°C | Ω/km | 300 | 192 | 130 | 114 | 73 | 60 |
| Impedance @1KHz | Ω | 994 | 796 | 665 | 660 | 500 | 445 |
| Impedance @100KHz | Ω | 147 | 134 | 127 | 125 | 124 | 122 |
| Impedance @512KHz | Ω | 120 | 118 | 117.5 | 117 | 116.5 | 116 |
| Impedance @1MHz | Ω | 117 | 115 | 114.5 | 114 | 113.5 | 113 |
| Maximum Average Attenuation @0.8KHz | dB/km | 1.64 | 1.30 | 1.1 | 1.04 | 0.9 | 0.74 |
| Maximum Average Attenuation @1KHz | dB/km | 1.68 | 1.35 | 1.14 | 1.08 | 0.93 | 0.76 |
| Maximum Average Attenuation @3KHz | dB/km | 3.18 | 2.52 | 2.3 | 2.01 | 1.74 | 1.42 |
| Maximum Average Attenuation @150KHz | dB/km | 11.4 | 8.3 | 7.2 | 6.2 | 5.7 | 4.4 |
| Maximum Average Attenuation @772KHz | dB/km | 24.3 | 19.4 | 17.4 | 15.4 | 13.1 | 10.8 |
| Maximum Average Attenuation @1000KHz | dB/km | 27.1 | 21.4 | 18.5 | 17.5 | 13.7 | 12.8 |
| Dielectric Strength | |||||||
| Conductor to Conductor (1min) | V DC | 500 | 500 | 500 | 500 | 500 | 500 |
| Conductor to Screen (1min) | V DC | 1000 | 1000 | 1000 | 1000 | 1000 | 1000 |
| Nominal Insulation Thickness | mm | 0.175 | 0.20 | 0.25 | 0.26 | 0.3 | 0.3 |
| Nominal Insulated Conductor Diameter | mm | 0.75 | 0.90 | 1.1 | 1.15 | 1.4 | 1.5 |
Mechanical and Thermal Properties
Temperature range during operation (fixed state): -30°C – +70°C
Temperaturerange during installation (mobile state): -20°C – +50°C
Minimumbending radius: 10 x Overall Diameter (unarmoured cables);15 x Overall Diameter (armoured cables)
Colour Code
Standard colour code is per IEC 60708 given in Colour Code Chart
Dimensions And Weight
Foam Skin Insulated and LAP Sheathed Jelly Filled Cable to IEC 60708
| Cable Code | Number of Pairs | Nominal Sheath
Thickness mm |
Nominal Overall
Diameter mm |
Nominal Weight kg/km |
|---|---|---|---|---|
| 0.4mm Conductor, 0.75mm Insulated Wire | ||||
| TP708-02YSF(L)2Y-10P04 | 10 | 1.5 | 9.0 | 82 |
| TP708-02YSF(L)2Y-20P04 | 20 | 1.5 | 10.0 | 120 |
| TP708-02YSF(L)2Y-30P04 | 30 | 1.5 | 11.0 | 161 |
| TP708-02YSF(L)2Y-50P04 | 50 | 1.5 | 14.0 | 239 |
| TP708-02YSF(L)2Y-70P04 | 70 | 1.5 | 15.0 | 315 |
| TP708-02YSF(L)2Y-100P04 | 100 | 1.5 | 18.0 | 434 |
| TP708-02YSF(L)2Y-150P04 | 150 | 1.5 | 21.0 | 630 |
| TP708-02YSF(L)2Y-200P04 | 200 | 1.8 | 24.0 | 824 |
| TP708-02YSF(L)2Y-300P04 | 300 | 1.8 | 29.0 | 1195 |
| TP708-02YSF(L)2Y-400P04 | 400 | 1.8 | 32.0 | 1556 |
| TP708-02YSF(L)2Y-500P04 | 500 | 2.0 | 36.0 | 1921 |
| TP708-02YSF(L)2Y-600P04 | 600 | 2.0 | 39.0 | 2282 |
| TP708-02YSF(L)2Y-800P04 | 800 | 2.5 | 44.0 | 2987 |
| TP708-02YSF(L)2Y-900P04 | 900 | 2.5 | 46.0 | 3364 |
| TP708-02YSF(L)2Y-1000P04 | 1000 | 2.5 | 49.0 | 3712 |
| TP708-02YSF(L)2Y-1200P04 | 1200 | 2.8 | 53.0 | 4411 |
| TP708-02YSF(L)2Y-1500P04 | 1500 | 2.8 | 59.0 | 5483 |
| TP708-02YSF(L)2Y-1800P04 | 1800 | 3.2 | 64.0 | 6567 |
| TP708-02YSF(L)2Y-2100P04 | 2100 | 3.2 | 69.0 | 7626 |
| TP708-02YSF(L)2Y-2400P04 | 2400 | 3.5 | 73.0 | 8663 |
| TP708-02YSF(L)2Y-2700P04 | 2700 | 3.5 | 77.0 | 9697 |
| TP708-02YSF(L)2Y-3000P04 | 3000 | 3.5 | 81.0 | 10729 |