EARTHING SYSTEM.doc

8/14/2019 EARTHING SYSTEM.doc

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INFORMATION SHEETPage 1 of 12

DEPARTMENT : TEACHING SKILLS DEVELOPMENT PROGRAM

SECTION : ELECTRICAL, ELECTRONIC AND TELECOMUNICATIONCOURSE : ELECTRICAL WIRING AND MOTOR CONTROL SYSTEM

DUTY : ELECTRICAL SYSTEMTASK : THREE PHASE SYSTEM Coe No! :TCTP"IS#

TITLE: INSTALL INDUSTRIAL SYSTEM EARTHING

PURPOSE:

This paper descriptions used to describe the system installation earthing system for electrical installations

DESCRIPTION:

1. Earthing system

Earthing system

The definition of grounding.

Grounding is a system of connections made between the metals in the electrical installation to the mass ofthe earth.

The importance of grounding.

Earthing function is to provide security to the user from electrical shock and fire hazards when the earthleakage current to flow to the covers the portion of metal parts that can carry current.

CENTRE FOR INSTRUCTORAND ADVANCED SKILL TRAINING,SHAH ALAM, SELANGOR DARUL EHSANMALAYSIA!


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A$%antages an$ $isa$%antages o" earthing system

a. Earthing system advantages:

i. The whole system is tied to its general mass of earth.

ii. All metals were included provided a path for leakage current to ground and cut the circuit.

b. The weakness of earthing system:

i. The cost of providing a complete grounding system is e!pensive.

ii. TT systems "use E#$%& where the source of the earth is not provided by the supplier if one

conductor is broken or dislodged earth connection there is no further leakage current path to the

mass of the earth is harmful to consumers.

'rotective conductor

$onductor protection formerly the earth continuity conductor. (t is a conductor that connects all parts

of the conductor "metal& in the assembly to the main earthing terminal. This includes earthing

conductor and bonding conductor.

)ow to determine the size of the cross*circuit protection of conductors in an installation manual.

The first way:

%y using +, - table below.

TA&LE '( )

$ross*sectional area

phase conductor "&

/inimum cross*sectional area conductor

circuit protection "'&

mm0

1

1 2 3+

4 3+

mm0

1

50


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6etermine the value of k in Table +,$ the value of k for pvc cable with protection as the coreconductor is 11+.

/etallic materials used as wiring systems such as conduits ducts or duct bo! can be used as aprotective conductor but must comply with (EE regulations the following:

(f the conductor cross*sectional area less than mm0 it must be insulated as well as strong andsturdy.

-or protection conductor is not insulated it must be protected from chemical reactions.

Each protective conductor connection must be made to comply with mechanical and electricalstrength.

-le!ible metal conduit can not be used as a protective conductor. eparate protective conductorshould be held.

'rotective conductor resistance is as follows:

a& -or the conductor of kumprum and aluminum must not e!ceed 1 ohm.b& -or a conductor such as pipe type kondit mains or suckers bo! must not e!ceed 7.+ ohm.

The things that cause high resistanceThe things that cause a high protective conductor resistance is as follows:

a. $auses of 8earth lug8 rustb. #oose wire connections.c. $oat of paint on electrical e9uipment.d. Ground cable connection at the plug and socket loose products.e. The connection between the conduit and terminal bo! loose.

/ulti*'rotective earthing. '/E "'rotective /ultiple Earthing&*T*$ "no use E#$%&

6efinition of multiple protective earthing.

This tool is used when the impedance of the faulty circuit to earth is low enough to operate a fuse orcircuit breaker is leaking to earth. ;hen it is invoked the consent of the supplier shall be obtained inadvance and is only used in low voltage only.


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Page No ' o" #!Earth e+e,tro$e

(ntroduction

Earth electrodes are rods "rods& stingy or strips planted in the ground to provide an effectiveconnection to the mass of the earth.

The types of earth electrodes.

$ommon ground electrode type used is as follows:

a& Galvanise pipe 0*3 m long ! > mm diameter.b& tem "rod& copper 0*3 m long ! , mm diameter.c& tingy 37 cm ! 37 cm.d& $opper trip "strip& 177 m ! 7., cm ! 3 cm.e& tructural steel buildings.f& lead and metal liner which covers the cable.

)ow do ( install the earth electrode

oil containing gas or o!ygen is not suitable for grounding the work because it can cause rust.Earth electrode must be buried deep into the soil and should be kept away from gas pipes waterpipes or cables.

Electrode must be buried in the soil is easily embedded electrodes. andy and rocky land isunsuitable for grounding the work so the electrode should be buried in other places that are notsandy or planted in a deeper level.;ays to reduce the resistance of earth electrodes

Among them are:

a& 'ut salt around the electrodes.b& 'lant in moist places.

c& Apply the iron powder around the electrodes.d& Apply the coal around the electrodes.e& 'ut sulfate solution.f& 'lanting two electrodes in parallel bars.g& /ake many hole electrode.h& (ncreasing the length or cross*sectional area of the electrode interface


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Lightning arrestors or +ightning .rote,tors /+ightning arrestor0 in the high1rise 23i+$ings

The purpose of the installation of lightning arrestors is to conduct resulting from lightning to theground to protect the building and electrical e9uipment. #ightning arrestors are usually installed in thetown which has a high electrical current and is e!posed as the substations high voltage lines the line

of low voltage building sub*station high*rise buildings factories which are flammable or e!plosive andother areas easier struck by lightning.

E9uipment for lightning arrestors

#ightning arrestors e9uipment is divided into three ma?or namely: *

i. rodii. conductorsiii. electrodes


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$onductors

The purpose of this conductor is the electrical current of lightning arrestor is the rod thatresult when the lightning struck by lightning arrestor rod to flow to the electrode. $onductor used iscopper tape.

Earth Electrode

-or installation on a small building such home ground electrode is usually used but for largebuildings and high ground electrodes are buried in piles of buildings and buildings with piles into theground.

DFB

Lightning Rod

Earth

Electrode

Earth

chamber

Copper

Tape


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STRUCTE O) LIGHTNING )LASH6THUNDER

This illustration is designed to demonstrate the main aspects and individual components ofa structural lightning protection system

# Do7n ,on$3,tor net7or8

The down conductor system is the means of carrying the current of a lightning strike safely tothe earth termination network

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!. -i!ings $onductor

'lant a conductor

3. Air Termina+s

@se air terminals in the form of vertical air rods for the protection of prominent roof topfeatures or e9uipment. @se strike pads to e!pose concealed conductors

( Air termina+ 2ases

$hoose the correct air terminal base. This will ensure that the vertical air rods are both solidlyfi!ed to the fabric of the structure and have a low resistance connection to the conductornetwork

' Con$3,tor ointing ,+am.s

elect a component for the interconnection of multiple conductors or for changes of direction.ointing clamps will ensure a low resistance corrosion resistant connection

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- Test ,+am.s

(n order to allow periodic disconnection and testing of the earth termination network select atest clamp to be placed within the run of each down conductor.

4 Earth e+e,tro$es

$hoose an earth electrode to suit the ground conditions in the locality of the structure.Electrodes are available in the form of rods and plates "lattice or solid&.

5 Earth ro$ ,+am.s

elect a high copper content alloy earth rod clamp for the connection of the earthing conductorto the earth rod. (n this below ground application the clamp must ensure a good electricalcontact and resist corrosion throughout the lifetime of the installation

9 Earth ins.e,tion ,ham2ers

(n order to allow periodic disconnection and testing of the earth termination network select atest clamp to be placed within the run of each down conductor

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EARTHING SYSTEM.doc