This document discusses different types of wires and cables used for power transmission. It describes common wire types like PVC wire and MICC wire and their advantages. It also discusses cable structure, classification based on insulation, conducting material and voltage rating. Cable termination and standard wire gauge for measuring current carrying capacity are also summarized.
2. Wires and Cables
Wires & Cables are purpose built conductors.
The size & type of wire/cable must suit the power rating required
for their use. The higher the power the thicker the wire/cable.
Uses of Wires
Domestic & small industry
Wiring in appliances
Uses of Cable
Small & big industries
Distribution Lines
Transmission lines
3. Wires
Various types of wires.
1.VIR wire:
• It is called vulcanized insulation rubber wire. Copper & aluminum
conductor and rubber coating are used in it. Now single & double
braided wires are mostly in a use. But it has lower tensile strength,
chemical reaction & bad insulation so it is not used.
• suitable for: low & medium voltage supply only
• old type: not readily available to purchase
4. 2. CTS & TRS wire:
It is called crab tyre sheath wire & tuff rubber sheath wire.
Hard & good rubber coating on copper wire is used in this
wire. Its used in house wiring & industrial wiring.
Available in 250/440V only
5. 3. Weather proof wire:
No weather reaction , in this types of wire. Because it has
cotton breeding with water proof. But it is flammable so no in use
now.
4. LC wire:
It is called lead covered wire. Lead pipe on rubber insulation
& its coating on conductor. It is very good in moisture condition
but less tensile strength so low uses now.
5. MICC wire :
It is called mineral insulated copper covered wire. In this type
wire copper conductor coated is with magnesium oxide. And After
copper coating is coated on it. In case of moisture weather PVC
coating (serving) is coated on its. It is uses in mines, factory,
furnace, boiler, rolling mills etc. magnesium oxide is used for
avoiding moisture problems.
6. 6. PVC wire:
It is called poly vinyl chloride wire. PVC coating on copper conductor so its
so many advantages as follows.
(a) High dielectric strength
(b) High tensile strength
(c) More defense against moisture
(d) High life
(e) No disturb in vibration
Available in 600, 660, 1100 Voltage, Widely used Long life Durable against
water, heat, oil, UV light
7. Three Core Wire
This is three core wire. It is pvc insulated wire.
Its used for 1-phase.
1.Blue wire for Neutral
(Returns current to power source)
2. Brown for live wire
(Provides current to appliance)
3. Yellow wire for earth
(Takes current to ground if appliance has fault)
There is color code used for wiring
&supply.
8. CABLE STRUCTURE
There is cable wire. Its
Use for power transmit ion.
1- core
2- pvc insulation
3- oil duct
4- metallic screen
5- rubber insulation
9. General construction & main parts of
cable
• Core
• Insulation
• Metallic sheath
• Bedding
• Armouring
Metallic Sheath: A power cable is an assembly of two or
more electrical conductors, usually held together with an overall sheath. The
assembly is used for transmission of electrical power.
Armouring: Armoured cable is the name given to any electrical cable
constructed with a layer of aluminium wire armour or steel wire armour. The
armour sits below the sheath of the cable to provide protection for the
conductor and insulating layers.
Bedding: Cable bedding compounds are mainly used in multi-conductor
cables, filling the spaces between conductors and making the cable round.
10. Classification of Cables
Type of insulation
1. Cotton covered
2. Silk coated
3. Asbestos covered
4. Rubber coated
5. PVC coated
Type of conducting material
1. Copper
2. Aluminum
11. Shape
1. Flat
2. Round
Mechanical Protection
1. Unarmored
2. Armored
Voltage Rating
1. Low voltage cable.(1000V)
2. High voltage cable.(11KV)
3. Super tension cable.(upto 132kV)
4. Extra high tension.(132kV and more)
5. Ultra high voltage cables(400kV and more)
12. Grading of cables
The voltage gradient is maximum at the surface of the conductor
and minimum at the inner surface of the sheath (i.e., the stress
decreases from conductor surface to sheath). This causes
breakdown in the insulation. For avoiding this breakdown, it is
advisable to have more uniform stress distribution throughout the
dielectric. The process of achieving uniform distribution in
dielectric stress is called the grading of cables.
13. S.W.G. (standard wire gauge)
Introduction
A Instrument which is use for measure Cross Area (gauge) of
wire
Various uses of wire gauge
• To measure Cross
area of wire
• To measure gauge
14. Standard Wire Gauge & Current
Carrying Capacity
Higher current will heat the
cable and damage the
insulation and may result in
short circuit
Each number
represents a size of
wire
Maximum safe
current that can flow
through a cable
15. Cable Termination
• When a cable enters into an accessory its called a termination
or Cable termination is the process of connecting power cables
up to the final equipment or the upstream circuit breaker.
• Thimble or terminals must be used at termination points, where
thimble is the termination point which can be connected to the
source or load.
• These must be as mechanically &
electrically strong as the conductor
or device which it is used.
16. Cable Safety
• Weather Proof
• Rust proof
• Free from wear and tear
• Armoured
• Good insulation
