Power Cables

Power Cables
We offer a comprehensive range of power cables available in plain Annealed copper. These power cables are further insulated with PVC. These wires are fire and heat resistant as well as these wire are insolvent to oil and water. These power cables are available in multi core armoured construction and various sizes.
Techno Flex manufacture high quality heavy duty power cable confirming to IS: 1554 (Part -1) L.T. 1100 volts grade
Construction Details


Plain bright annealed copper / alluminium, solid / stranded conductor confirming to IS: 8130: 1984.


Type A, B, & C (HR) grade according to IS: 5831 : 1984 amended up dated.


Inner sheathing shall done by extrusion or by PVC tape binding that laid up cores shall not loose and prevent to water entering.


Gl armour wire / strip provides not only mechanical support but also earthing. The material use an according to IS : 3975 : 1974 amended up dated.


Extruded STI / ST2(HR, FRLS, Halogenfree FRLS) type PVC is used according to IS : 5831: 1984.


In Thermal Power Station; Petrochemical Refineries; Steel & Cement Plant; Distribution System; Digital Control and Monitoring & Information systems; Air Ports; Building Towers; etc.
Techno Flex manufacture heavy duty Power Cable comprising of cores Single / Two / Three / Three & Half / Four Of Alluminium Conductor, PVC Insulated cores laid up, PVC Inner Sheathed OR PVC tape binding, GI wire / Strip Armoured & overall PVC sheathed cable confirming to IS : 1554 : Part-I.
Basic assumption for Current ratings
(1) Max. Conductor Temp. : 70°C
(2) Thermal resistivity soil : 150°C CM/W
(3) Thermal resistivity of rvc : 650°C CM/W
(4) Ground temperature : 30°C
(5) Amb. air temperature : 40°C
(6) Depth oflaying : 75 cm
     (highest pt. of cable laid)
Rating Factors
1. Rating Factor for depth of laying Twin & Multicore Cables
Depth Of laying cm upto 25mm2 Above 25mm2 & 300mm2 Above & 300mm2 Multicore
75 1 1 1 1
90 0.99 0.98 0.97 0.99
105 0.98 0.97 0.96 0.98
120 0.97 0.96 0.95 0.97
150 0.96 0.94 0.92 0.96
180 or more 0.95 0.93 0.91 0.95
2. Rating Factor for the Single Core Cables (AC) in the formation in Air Applied to the corresponding ratings for trefoil groups in air.
Nominal Area Of Conductor mm2
Rating Factor
Upto & Including 185
3. Rating Factor for variation in underground temperature for cables laid direct in ground & laid in duct.
Ground Temperature 0C 15 20 25 30 35 40 45
Rating Temperature 1.17 1.17 1.17 1.17 1.17 1.17 1.17
4. Rating Factor for variation in underground temperature for cables laid direct in ground & laid in duct.
Ground Temperature 0C 15 20 25 30 35 40 45
Rating Temperature 1.33 1.25 1.16 1.09 1.0 0.90 0.83
Short Circuit Rating Of Alluminium Conductor Cable :
Techno Flex cables manufacturing method based on quality assurance plan & use of high standard raw material, therefore it withstand high Magnitude of short circuit rating. It is calculated as under:
where    Ish --> short circuit ratings in r.m.s. amp.
             t --> duration of short circuit in seconds
             A --> Area of conductor in sq.mm
Tabulated The Constant For Different Duration Of Short Circuits :

Duration of Short Circuit in sec.

1 Cycle = 0.02 sec

2 Cycle
= 0.04 sec

5 Cycle
= 0.1 sec

10 Cycle
= 0.2 sec

25 Cycle
= 0.5 sec

50 Cycle
= 1.0 sec





Short Circuit constant Per unit area











Example: Short Circuit rating of 70 sq.mm area of conductor with short duration 0.5 sec = 70 x 107 = 7490A
Recommendation For Installation:
Cables are the most important asset of any organization. Any damage to it will result in break down of the complete plant & machinery, hence proper attention should be paid while handling and laying them. So for its silent features which should be kept in view during installation as under:-
1. Before laying the installation ofthe cable, It should be checked by meggar as a preliminary check against any probable fault.
2. The drum should be always rolled in the direction of the arrow or opposite to the outside cable end.
3. Avoid the possibility cable twist which will brutally damage the cable because cable have itself twisting force.
4. Properly check the sequence of cores & no crossing of cores while connecting, also decide the direction in which the cable is to be pulled.
5. Possible bending radius should be 12 times the overall diameter of the cable to be maintained. But at any case it should not be less than 8 times.
6. In low temperature area the bending should not be very small radius because PVC compound become stiff & brittle and it shall get crack.
7. All joints terminations armour wires & external metallic bonding should be connected to the earth, wherever possible armour at one end of the cable should be connected to main earth system at the supplying end by employing metallic connectors.
Precautions should be taken to eliminate the chemical & by metallic corrosion ofthe earth connector.
8. The design of the box & composition of the filling compound should provide an effective sealing against entry of moisture to conductor & annour connector.
9. If hot pouring protective compounds are used, the temperature of the compound while pouring should not exceed 150°C.
10. Where the cables are crossing the roads, the same should be laid in concrete ducts & avoid the sharp edges of concrete ducts in other hand cable may be damaged.
11. We strongly recommend the user that after installation, 2KV DC voltage test should be carried out, through the each core before earthing.
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