Subscribe

0

Enterprise Telecom Services

Telecom Cable Jelly or Foam ?

author-image
Voice&Data Bureau
New Update

Conventionally, for telephone networking, jelly-filled
underground telephone cables have been used in our country, since the mid-80’s.
This type of cable replaced the old Paper Insulated Cables (PICs), which were
predominantly used earlier. However, due to its design and other
characteristics, several problems were encountered, especially during the
monsoons when due to the seepage of water into the cable core, the cable used to
malfunction and caused breakdowns in telephone services.

Advertisment
Performance
Test Result

Major global companies have conducted studies on
performance of foam skin cables underground, and the results are as
follows:

  • Mutual capacitance variation is less than ± 2
    percent

  • Attenuation variation is less than ± 2 percent

  • Unbalance to ground variation is between 5 — 20
    percent.

  • No change in appearance of copper found

  • No oxidation of copper

  • Insulation colors distinguishable

  • OT values remain at 80 to 120 minutes

  • ESCR results good after 1,000 hours of testing time

  • HV, IR and breakdown tests all meet requirements

  • Wirebull analysis indicates 30 to 35 years of service life

By switching over to jelly-filled cables, where jelly is used
as a water-resistant compound, telephone services have improved to a large
extent, and customer satisfaction level has also increased considerably. Slowly,
all PICs are being replaced by jelly-filled cables in the country’s telephone
networking areas, thus, hopefully overcoming the problems faced by the consumer.

However, in developed countries, an improved or advanced
version of jelly-filled cable is used. This cable is called ‘Foam Skin’ type
of cable and has various advantages over the currently-used solid jelly-filled
cable.

Advertisment

The saving on costs by using ‘Foam Skin’ cable over the
conventional solid filled cable is approximately 8 percent. While being
cost-effective, the ‘Foam Skin’ cable retains all its technical
characteristics and, as such, has become acceptable in many countries all over
the world. Today, even developing countries in Africa, Middle East and South
East Asia, have standardized on using ‘Foam Skin’ type of cables in their
networking, and repeat tenders or orders are a proof of its acceptability.

In our country, the annual telephone cable requirement costs
approximately Rs 3,500 crore. However, the main cable used still remains the
conventional type– solid jelly-filled insulated cable, as the concept of using
‘Foam Skin’ type of cable is yet to catch on, in our country’s networking
area. This is, in spite of the fact that there is a valid specification
formulated by the concerned government body. If one has to calculate the saving
to the exchequer on the annual purchase, the government will end up saving
approximately Rs 275 to Rs 300 crore annually, on its cable purchases.

Advantages

  • Electrical parameters are exactly the same as that
    of the conventional solid jelly-filled cable

  • Due to lower dimensions, the cable weight is lower,
    and is easy to handle in a filed environment

  • Cost of the cable is approximately 8 percent than
    the conventional cable

  • Cable diameter being lower, it can be accommodated
    in smaller duct size

  • The wooden drum size will be lower, by saving
    precious natural resources

  • Freight cost will be lower

  • Already in use in all the developed countries and also developing
    nations in Africa, Middle East, South East Asia

By our correspondent