zone 2 for generators

7/25/2019 zone 2 for generators

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Area Classification

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:Area Classification of Hazardous Areas

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(Zone0, Zone 1 & Zone 2)

)(Division 1 & Division 2.

)( :((Zone 0.

( :(1)(Zone 1.

( :(2)(Zone 2,

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:

.((Class I

ustsD Fibers & Flyings

Class II & Class III.Class I,NEC

) (1)(Division 1( )( (1)(Zone 0 & Zone 1

.

1998 (DIN VDE14-IEC / EN 60 079

0165 part 1. )

Zones10-IEC / EN 60 079(DIN VDE 0165 part 101)

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, InternationalRecommendations National Standards

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1-.

2-Type of Protection:

-Apparatus ConstructionEnclosure

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Apparatus Group .

Temperature Classification.

rotectionType of P:

1-( (d

Flameproof Enclosure Type of Protection (d):

,

.

( (.53

1-IEC 60 079EN 50 018.

Exd

Principle:


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Parts which can ignite an explosive atmosphere are enclosed inan enclosure, that withstands the explosion pressure in itsinside and prevents the transfer of the explosion to theenvironment.

Applications:

Switchgear, control equipment, display devices, control panels,motors, transformers, lighting fittings and other sparking parts

Exd

2- ( ) ( e)

Increased Safety (Type of Protection (e):

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7-IEC 60 079EN 50 019.

Exe

Principle:

Increased safety is a type of protection by which measures areapplied to prevent with a major degree of safety the possibilityof excessive temperatures and of the occurrence of arcs andsparks in the interior and on the external parts of electrical

apparatus, which does not produce them in normal operation.

Applications:

Terminal boxes,control stations for the installation ofequipment which is protected by another type of protection,squirrel-cage motors, lighting fittings


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Increased safety is together with flameproof enclosure theeconomically most important type of protection. Typical devicesare terminal boxes and junction boxes.

It is not possible to construct electrical equipment by whichexcessive temperatures, sparks and arcs could occur in normal

operation only with this type of protection. It is state of the art toprotect sparking devices with the combination Ex de: Protectionof the contact by a flameproof enclosure; Protection of theterminals by increased safety.

Some features of increased safety:

Avoidance of separate influences by a minimum degree ofprotection IP 54

Impact resistance of at least 7 Nm with IP 54 (non-translucentmaterial)

Avoidance of Sparks and arcs by means of increasedclearances and Creepage distances

Special requirements for terminals (e.g. protection against self-loosening)

Avoidance of excessive temperatures by means of an

appropriate construction of the equipment so that also by acertain overload no Inadmissible temperatures could occur.

Increased Safety Exe

3-( P)

Pressurized Enclosure Type of Protection (P):

( 5 )

.,

. IEC 60

3-079EN 50 016.

Exp


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Principle:

The entry of a surrounding atmosphere into the enclosure of theelectrical apparatus is prevented by maintaining, inside theenclosure, a protective gas at a higher pressure than that of thesurrounding atmosphere. The overpressure is maintainedeitherwith or without a continuous flow of the protective gas.

Applications:

Control panels for the installation of large (Non Ex) equipment,whole rooms for electrical installations, diagnostic equipment,PCs

Possibilities of the technical realization:

without feeding a protective gas (static pressurized apparatus)

feeding a protective gas only to compensate leakages with acontinuous flow of the protective gas

For static pressurized apparatus the following conditions arenecessary:

The protective gas has to be inert (no reaction with oxygen)

The enclosure has to be filled in thesafe area with the inert gas


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Two independent safety devices are required which switch offautomaticallyin case of a loss of pressure. The reactivation isonly allowed to be possiblewith tools.

Pressurized apparatus with leakage compensation orcontinuous flow of the protective gas:

Flammable gases are not allowed to be inside of the enclosure,whenswitching the apparatus on (Purging required).

An automatic switch off is required in case of pressure loss.

The exit apertures have to be outside ofthe hazardous area, ora device is needed which safely prevents the stepping out ofsparks.

Because of the high efforts and expenseswhich are necessaryto control the safety of such apparatus, they were only used forlarge applications.

4-( (i

Intrinsic Safety (Type of Protection (i)):

Specified Fault

.Prescribed Test Condition

.

. (ia)(ib) . IEC 60 079 11

EN 50 016

Ex i


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Principle:

The electrical equipment which is installed in the hazardousarea has to have only intrinsically safe circuits.

A circuit is intrinsically safe, when no spark or heat is able toignite an explosive atmosphere under fixed conditions. Thesepredefined conditions include the normal operation and certainfailure modes.

Applications:

Instrumentation,Information technology

This type of protection uses the fact, that a specific energy isneeded to ignite an explosive atmosphere. Therefore a circuit isintrinsically safe, if its voltage and current does not exceedspecific limits and if it is not possible to cause an ignition undercertain testing conditions and safety factors.

Intrinsic Safety is suitable especially for applications with lowenergy consumption, e.g. instrumentation and informationtechnology.

It is important to differ between an intrinsically safe electricalapparatus, which contains only intrinsically safe circuits and an

associated electrical apparatus, which contains intrinsically safeand non-intrinsically safe circuits.


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An associated electrical apparatus has to be installed in the safearea, because of its non-intrinsically safe circuits.

Intrinsically safe electrical apparatus and circuits are divided intwo categories:

Electrical Circuits with category ia are provided for the use inZone 0 and higher.

Electrical Circuits with category ib are provided for the use inZone 1 and higher.

Category ia has a higher degree of safety than category ib,which is caused by a different fault determination during thetesting of these categories.

5-( o)

Oil Immersion (Type of Protection (o)):

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,,

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,((o

( .2)(Zone 2) -IEC 60 0796EN 50 015.

Ex o


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Principle:

The electrical apparatus or parts of the electrical apparatus areimmersed in oil in such a way that an explosive atmospherewhich may be above the oil or outside the enclosure cannot beignite

Applications:

Transformers

(hardly used any more

Oil immersion prevents the connection of an explosiveatmosphere with an ignition source by enclosing the electricalapparatus with oil.

In these days this type of protection has practicallydisappeared.

Mineral oil is, if it is new, is a very good isolator, but it has thebig disadvantage that is very hygroscope and that it soots

because of the disintegration in the arc.

Switchgears with this type of protection need high maintenanceefforts, otherwise there is the possibility of short-circuits andconductible bridge contacts.

Beside mineral oil according to IEC 29 there are other protectivefluids allowed (e.g. silicone oil). The name oil immersion staysthe same.

6-

(

q)

filled (Type of Protection (q))-Sand:

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. IEC5-60 079EN 50 017.

Ex q


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Principle:

The enclosure of an electrical apparatuses filled with a materialin a finely granulated state so that, in the intended conditions ofservice, any arc occurring within the enclosure will not ignitethe surrounding atmosphere. No ignition shall be caused eitherby flame or by excessive temperature of the surface of theenclosure.

Applications:

Transformers, capacitors, electronic Parts, (not often used)

This type of protection is not able to prevent the incoming ofhazardous atmosphere into the enclosure in each case. Thoughan internal ignition of the atmosphere is possible, but anexternal will be prevented.

This extinction is done by means that the free internal volume inthe powder filling is very small which causes the suppression ofthe flame of a potential internal explosion.

The filling material is quartz sand or other mineral particles.

The electrical apparatus has to be protected against short-circuit and thermal overload so that the limiting temperatureclass on the surface of the enclosure will not be exceeded.


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The maximum short-circuit current has to be limited to 1500Amps or a safe current limitation has to be installed in order toprotect the powder filling against destruction by an arc.

7-( S)

Special Protection (Type of Protection (s)))):

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. (Molding)..

EncapsulationExm18-IEC 60 079EN 50 028.

Ex m

Principle:

Parts that could ignite an explosive atmosphere are enclosed ina resin sufficiently resistant to environmental influences in sucha way that this explosive atmosphere cannot be ignited either bysparking or heating which may occur within the encapsulation.

Applications:


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Switchgear for low power,control equipment,display devices,sensors

When using this type of protection to encapsulate electronicparts it is necessary to guarantee that an internal fault is notable to inactivate the protection.

For example electrolytic capacitors have to be installed andencapsulated in such a way, that a response of the pressurerelief device is not able to destroy the encapsulation.

Besides these facts this type of protection requires much effortin constructing and testing the equipment

8-(

2

( )N)

Apparatus for Zone (2) (Type of protection (N)):

Sparking Type)-(Non(Increased Safety)

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( . (2

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. 15-IEC 60 079

EN 50 021.

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:

( 1( )2).

((EEx.((Ex

:Temperature Classification

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T6T145085IEC

T3DCBAT2 ABCT4A

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80%

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AmbientTemperature40

.40

)VDE G1 toG5)

(T5T1. (

:T6)(T1

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Relationship Between T Class & International Standards


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Apparatus Gas Grouping:

1Group IIEC. )(

2

Group II

AII

BII

CII

(Groups II, III& IV)229

((FlameproofExd.Intrinsically Safe

((Gaps((Flame Paths

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zone 2 for generators