CABLES AND WIRES - Novkabel

Laying of CablesGeneral conditionsCables can be laid in the ground, water, open space, air, on trays, in cable channels and tubesand enclosed spaces.The laying of cables should be carried out carefully in order to avoid cable damage, not onlyduring the laying process, but also later in operating conditions.It is important to take care of the following:- The laying should be carried out at appropriate temperature that shall not cause anydamages to cables or endanger the safety of people and equipment;- Cable stretching should be performed by a stretching device equipped by a tensile strengthcontrol;- When laying in the ground, a cable should always be laid on a prepared bedding, which mustnot have aggressive influence on the sheath;- Cables must not be dragged over the ground, especially not over stony terrain;- You should respect the permitted bending radius;- Cable trench should not be covered up with rough stones;- Protections and warning tapes should be placed over the cables;- Cable ends should be closed by watertight caps during laying and transportation.Laying TemperaturePVC sheathed cables could be laid at ambient temperature up to -5 O C, whereas PE sheathedcables could be laid at ambient temperature up to -20 O C.In case the ambient temperature is lower during laying, the cables should be warmed upapplying one of the adequate methods (e.g. by keeping them in warm room). One of thepossible methods includes the use of heaters placed at an appropriate distance from thecables. Additionally, the cable reels should be rotated occasionally, taking care that even thelowest cables remain sufficiently heated. Cables can also be heated by electrical power.Permitted Pulling Force238In case of cable grip application, the following pulling forces have been permitted, based onthe principle that the elongation of conductor material shall not exceed 0,2%:- for Cu conductors F ≤ n x q x 50 N/mm 2- for Al conductors F ≤ n x q x 30 N/mm 2Where: F – pulling force (N),n – no. of conductors in a cable (or no. of cables),q – conductor cross-section (mm 2 ).In case of cable stocking application, the following pulling forces have been permitted:- for steel-wire armored cables F ≤ 12 x Ø 2- for steel-tape armored cables F ≤ 3 x Ø 2- for all other types of cables F ≤ 5 x Ø 2Where: F – pulling force (N),Ø – cable diameter (mm).When applying the cable stocking in the process of cable laying, the part of the cable coveredby the stocking should be obligatorily cut off after traction.