submision of building services

8/12/2019 Submision of Building Services

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Submitted to Nikhil Vyas sir,From

Ar-0711 Gandhi Shaily.

Ar-2911 Rawal Aneri.

Ar-0812 Gajera Aabha.

Id-0911 Kansara Niki.

AssignmentTypes of wires


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TYPES OF WIRES & CABLES


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INTRODUCTION.


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INTRODUCTION TO WIRES There are mainly 6 types of wires are there.

vulcanised indian rubber wire (V.I.R)

tough rubber sheathed wire (T.R.S)

poly vinyl chloride wire (P.V.C.)

Lead alloy sheathed wire

weather proof wires

flexible wire


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V.I.R (Vulcanised Indian Rubber)

wires.

A VIR wire mainly consists of a tinned conductorhaving rubber coating.

Tinning of conductor prevents the sticking of rubberto the conductor.

Thickness of rubber mainly depends on the operatingvoltage to which wire is designed.

A cotton bradding is done over the rubber insulationsto protect the conductor against the moisture.

Finally the wire is finished with wax for cleanliness.

Nowadays these wires are not used since a betterquality wires are available at a cheaper rate.


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T.R.S. (Tough Rubber Sheathed)

wires.

This type of wire is a modification of V.I.R. wire. Itconsist of the ordinary rubber coated conductors withan additional sheath of tough rubber.

This layer provides better protection against moistureand wear and tear. Also it provides an extra insulation.

These wires are generally available in singleconductor, two conductors or three conductors.


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P.V.C. (Poly Vinyl Chloride) wires.

This is the most commonly used wire for wiringpurpose.

Conductor is insulated by poly vinyl chloride(insulating material).

P.V.S. has following properties:1. Moisture proof.

2.Tough.

3.Durable.

4.Chemically inert.

But it softens at high temperatures therefore notsuitable for connection to heating appliances.


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Lead alloy sheathed wires.

The ordinary wires can be used only at dry places butfor damp places these wires are covered withcontinuous lead sheaths.

The layer of lead covering is very thin like 0.12 cm

thick.These wires provides little mechanical protections to

the wires.


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Weather proof wires.

These types of wires are used outdoor i.e. providing aservice connection from overhead line to building etc.

In this type of wire the conductor is not tinned and theconductor is covered with three braids of fibrous yarnand saturated with water proof compound.


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Flexible wires.

These wires consists of number of strands instead of asingle conductor. (Strand is a very thin conductor).

The conductor is insulated with P.V.C. material.

These wires are very useful for household portable

appliances where flexibility of wire is more important.Typical specifications

55/.01mm(55 strands of 0.1mm diameter), maximumcurrent 6A,used for household purposes.


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INRODUCTION TO CABLES.

A power cable is an assembly of two or more electricalconductors, usually held together with an overallsheath. The assembly is used for transmission ofelectrical power. Power cables may be installed as

permanent wiring within buildings, buried in theground, run overhead, or exposed.

Flexible power cables are used for portable devices,mobile tools and machinery.


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GENERAL CONSTRUCTION.

1. Conductor or Core.

2. Insulation.

3. Metallic Sheath.4. Bedding.

5. Armouring.

6. Serving.


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TYPES OF CABLES.

The types of cables basically

decided based on the voltage

level for which it is manufactured

and material used for the insulationsuch as paper,cotton,rubber etc. the

classification of cables according to

the voltage levels is,

Low Tension Cables (L.T. Cables).Medium and High tension Cables

(H.T. Cables).


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BELTED CABLES.These cables are used for the

voltage level up to 11 kV. The

construction of belted cable is

is shown in fig.

The cores are not in circularshape.

The cores are insulated from

each other by use of impregnated

paper.The gaps are filled with fibrous

material like jute.

The belt is covered with lead

sheath.


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SCREENED TYPE CABLES.

These cables are used for the voltage levels of 22 kV.The two types of screened cables are:

H-Type cables.

S.L. Type cables.


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H-Type cables.

Designed by M. Hochstetler andhence named H-type cable.

No paper belt in this type of

cable.

Each conductor is insulated

with a paper, covered with a

metallic screen.


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S.L. Cables.

S.L. leads for Separate Lead

Screened Cables.

Each lead is insulated with an

impregnated paper than

covered by separate sheath

lead.


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SUPER TENSION (S.T.) CABLES.

The S.T. cables are intended for132 kV to 25 kV voltage levels.

In such cables, the following

methods are specially used to

eliminate the possibility of

void formation:

Instead of solid type insulation,

low viscosity oils under pressureis used for impregnation.

Using inert gas at high pressure in

b/w the lead sheath & dielectric.


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OIL FILLED CABLES

In case of oil filled cables, thechannels or ducts are provided

within or adjacent to the cores,

through which oil under pressure

is circulated. It consists of concentric standard

conductor but built around a hallow

cylindrical steel spiral core, which

acts as a channel for oil.


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GAS PRESSURE CABLES

An inert gas like N at high pressureis introduced lead sheath and

dielectric.

Gas like SF6 is also used in

cables.

Pressure is about 12-15

atmosphere.

Working power factors isalso high.


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THANK YOU

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