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Design

We have considered four major parameters of cable design to illustrate the proper design

Conductor

The heart of the cable is the Conductor. (Unfortunately, many manufacturers do not acknowledge this fact and go on basis of their conveniences / machine availability.)

A comparison of number of strands used by us vis-à-vis others are shown below:

NUMBER OF STRANDS USED IN CONDUCTOR

SIZE IN SQ.MM MINNIMUM NO. OF WIRES IN COMPACT CONDUCTOR AS PER BS/IEC MIN. REQMT.
RCL S-1 S-2 S-3
70 19 15 12 15 12
240 37 36 30 37 30
400 61 58 53 58 53

From this, you can see that it is plain engineering that 12/15 wires cannot form a uniform circle.

Hence when such conductors are shaped, they have gaps, sharp edges in between the wires, which may lead to failures, after a period of time.

Gaps also increase Conductor Resistance

A properly designed conductor is smooth and compact. (Visuals) Of course even with proper number of wires, if the compaction is not proper, it can lead to air gaps, which increase conductor resistance.

  • A Bad Design of Conductor Can Cause
  • 3% to 9% Transmission loss, Failure due to Sharp Edges.

Insulation

A good Insulation should have:

High insulation resistance
High dielectric strength
Good mechanical properties
Tenacity & elasticity should not be affected by chemicals.
Should be non-hygroscopic.

  • At RCL we use Raw materials with Dielectric strength of 36 to 40 kV/cm (About 90% higher than its original value)

Our Insulation Resistance Values are

  • 350 Mega Ohm for PVC
  • 2000 Mega Ohm for XLPE

Uniformity of insulation thickness & eccentricity.

  1. Avoids increase in charging current and lessens the voltage drop.
  2. If dielectric is not uniform, it leads to increase in the capacitance of the conductor and resultant higher temperature.

Armouring

  • Armouring protects the cable from mechanical damage.
  • We maintain 98-100% coverage to protect the cable from any mechanical damage because of sharp edges.

Outer Sheating

  • This Protects the Overall Cable
  • As a practice in RCL we offer sheathing with ST, FR & Higher Oxygen Index Properties for all PVC & XLPE cables.

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