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Examoogle • User • info@examoogle.com • EE-2024-8821
Chapter 1 of 12 • Page 1 of 248🔒 Protected PDF • Watermarked
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The bedding on a cable consists of
hessian cloth
jute
any of above
none of above
any of above
Quick Summary: The bedding of an underground power cable is a protective layer placed between the metallic sheath and the armouring. It serves to cushion the sheath against the mechanical pressure exerted by the armouring wires or tapes.
The bedding of an underground power cable is a protective layer placed between the metallic sheath and the armouring. It serves to cushion the sheath against the mechanical pressure exerted by the armouring wires or tapes.
P=AF — Where P represents the pressure reduced by the bedding layer through increased surface area distribution of the armouring force.
The bedding material, typically fibrous such as hessian cloth or jute, is treated with a bituminous compound to prevent corrosion of the metallic sheath. Its primary mechanical role is to prevent the hard metallic armour (steel wires/tapes) from causing indentations or punctures on the lead or aluminium sheath during the cable manufacturing process or during laying.
Bedding is composed of fibrous materials like jute or hessian.
It is always impregnated with preservative compounds to resist moisture and decay.
It acts as a buffer layer between the delicate sheath and the rugged armour.
Without bedding, the metallic sheath would suffer from direct mechanical damage.
Prevents corrosion of the metallic sheath.
Provides mechanical cushioning against armour pressure.
Inexpensive and easy to apply during manufacturing.
Susceptible to moisture ingress if the outer serving is damaged.
Adds to the overall thickness and weight of the cable.
Underground transmission and distribution cables.
Submarine power cables.
The sequence of layers from inner to outer is: Core, Insulation, Metallic Sheath, Bedding, Armouring, Serving.
Hessian is a woven fabric made from jute or other vegetable fibers, widely used for its cost-effectiveness in cable bedding.
C is correct — Bedding can consist of either hessian cloth or jute, as both serve the required function of protecting the metallic sheath.
Always remember the order of cable layers: S-B-A-S (Sheath-Bedding-Armour-Serving). If you forget the order, recall that the protective layer (bedding) must sit directly beneath the protective armour.