| Sl. No. |
Description |
| 1.0 |
SCOPE : |
1.1 |
This specification covers the requirements and tests for armoured and unarmoured single core, twin core, three core and multi-core copper conductors pvc insulated and sheathed cables for railway signaling. This specification covers the complete requirement of underground (u/g), unscreened (u/s), railway signalling cable.. |
| 1.2 |
The cable covered in this specification shall be suitable for use on AC systems (earthed or unearthed) for rated voltages upto & including 1100 volts. These cables may be used on DC systems for rated voltages upto and including 1500 volts to earth. |
| 1.3 |
The cables covered in this specification or suitable for use where the combination of ambient temperature and temperature rise due to load results in a conductor tempretaure not exceeding 70°C. |
| 2.0 |
GENERAL REQUIREMENTS : |
| 3.0 |
CONDUCTORS : |
| 3.1 |
a) Diameter : 0.90mm ± 0.02 mm.
b) Maximum Resistance : 28 Ohm/Km At 20°C.
c) Maximum, Loop Resistance : 56 Ohm/Km At 20°C.
|
| 4.0 |
INSULATION (DIELECTRIC) |
| 4.1 |
Each conductor shall be insulated with solid polythene of MDPE or HDPE.
Recycled or reclaimed material shall not be used.
|
| 4.2 |
Minimum diameter of Insulated Conductor : 1.55 mm |
| 4.3 |
Nominal Insulation Thickness : 0.325 mm |
| 4.4 |
The colour scheme of polyethylene insulated quads shall be as per Table given below |
| |
| Colour of the conductor insulation |
| Quad No |
| |
A- Wire |
B-Wire |
C-Wire |
D-Wire |
| 1. |
White |
Orange |
Red |
Grey |
| 2. |
White |
Blue |
Red |
Grey |
| 3. |
White |
Brown |
Red |
Grey |
| 4. |
White |
Green |
Red |
Grey |
| 5. |
White |
Yellow |
Red |
Grey |
| 6. |
White |
Black |
Red |
Grey |
Note : Wire A and wire B shall form a pair. Similarly wire C and wire D shall form a pair. |
|
| 5.0 |
QUADDING : |
| 5.1 |
Four conductors insulated as above shall be standard to form a star quad each, two conductors diagnonally opposite forming one pair and the remaining two diagnonally opposite conductors forming the second pairs of the quad. Polyethylene centre strings of required diameter may be used. The quad shall be held together firmly by means of an open helical whipping of cotton / nylon yarn or coloued tape of suitable material of appropriate thickness. |
| 5.2 |
The colour scheme of the quad whipping shall be in accordance with the Table given below
| QUAD NUMBER |
COLOUR SCHEME |
| 1 |
Orange |
| 2 |
Blue |
| 3 |
Brown |
| 4 |
Green |
| 5 |
Yellow |
| 6 |
Black |
|
| 6.0 |
LAYING UP : |
| 6.1 |
The quads shall be assembled to form a symmetrical core with a right lay. Polythene strings of required diameter may be used as fillers, if necessary, for proper circular core formation. |
| 6.2 |
Each quad shall retain its position in the cable with reference to the other quads. The manufacturing process shall be such that there is no physical displacement of the quads, either during manufacture of the cable or during its subsequent handling. |
| 7.0 |
FILLING COMPOUND (JELLY) : |
| 7.1 |
The cable core shall be fully filled with a suitable water resistance compound like jelly which is fully compatible with the polythene insulation of the conductors. |
| 9.0 |
CORE WRAPPING : |
| 9.1 |
Polythene coated aluminum tape shall be applied longitudinally on the quad with a minimum overlap of 6mm. The thickness of aluminium tape shall be 0.20 mm ± 10% & that of polythene / copolymer coating on each side 0.05mm nominal. The thickness of composite tape shall be 0.3mm ±15%. |
| 10.0 |
INNER SHEATH : |
| 10.1 |
Cable shall be sheathed with the polythene grade 03C or H03C as per BS:6234. and containing a suitable anti-oxidant system. The material shall be virgin as per ASTM-D-883. |
| 10.2 |
The sheath shall be reasonably circular, free from pinholes, joints and other defects. The nominal thickness of sheath shall be 2mm (excluding Poly-Al. laminate). The minimum thickness shall not be less than 75% of the specified nominal thickness. The average of six measurements, equally place around the circumference, shall not be less than 85% of the specified nominal value. |
11.0 |
SCREENING |
| 11.1 |
The cores with inner sheath shall be surrounded by a reasonably close fitted screen of aluminum in the form of wires/strips |
| 12.0 |
PROTECTION : |
| 12.1 |
The aluminum screen shall be wrapped with a single layer of woven tape impregnated with Barium chromate with minimum 20 % overlap |
| 13.0 |
INTERMEDIATE SHEATH : |
| 13.1 |
Further protection for the screening shall be provided by extruded PVC sheath over screening. Its shall be circular. |
| 13.2 |
The PVC used for intermediate sheath shall meet the requirement of ST-1 (General purpose sheath for use at maximum rated conductor temperature 70 Deg. C) compound of IS : 5831-84, Re-cycled or re-claimed material shall not be used. |
| 13.3 |
The colour of the intermediate sheath shall be Grey |
| 14.0 |
ARMOURING : |
| 14.1 |
The galvanized steel tape armouring conforming to IS : 3975 shall be applied tightly over the intermediate sheath with two layers. The armour shall be free from rust, blooming, oxidation, cracks, splits etc |
| 14.2 |
The armour shall be lapped as per IS : 692-1973. The intermediate sheath shall not be visible throughout the length of the cable |
| 14.3 |
The direction of the lay of the armour shall be opposite to that of the outermost layer of screening |
| 15.0 |
OUTER SHEATH : |
| 15.1 |
The outer sheath shall be applied by extrusion in one continuous process over the armouring and shall be homogenous and free from joints and repairs. |
| 15.2 |
The PVC used for outer sheath shall meet the requirement of ST-1 (General purpose sheath for use at maximum rated conductor temperature 70 Deg. C) compound of IS : 5831-84, Re-cycled or re-claimed material shall not be used. |
| 15.3 |
The colour of the outer sheath shall be Black. |
| 16.0 |
MARKING : |
| 16.1 |
The following information shall be legibly and indelibly indicated at every meter or less throughout the length of cable by embossing or engraving / indenting on outer sheath of the cable. All the marking shall be in white or yellow colour. The marking shall be clear, distinct and visible to the naked eye from a distance of about 1 meter, the size of marking shall be of minimum 3mm |
| 16.2 |
-
Name or trade mark of the manufacturer.
- IRS-TC 30-05
- Month and year of manufacture.
- Cable Drum number.
- Sequential length marking at every meter with an accuracy of ± 0.2%.
|
| 16.3 |
Finished cable is being supplied in non returnable wooden drum. |
