ECX4234 Lesson 2

ECX4234 – Session Lalith A. Samaliarachchi

2

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The

Session 2 The wiring regulations

Contents

2.1 2.1

Hist Histor ory y of the the IEE IEE wiri wiring ng reg regul ulat atio ions ns

2.2

Plan of the 17th edition of the IEE regulations

2.3 2.3

Defi Defini nitio tions ns use used d in the the regu regula latio tions ns

2.4 2.4

Symb Symbol olss use used d in in the the regu regula lati tion onss

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Aim he aim of this session is to tea!h you the basis of the IEE "iring #egulations$ get an

idea about the meanings of some terms and symbols used in ele!tri!al installation .

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Specific Objectives %t the end of this session you will be able to

1.

&riefly re!all the history of the "iring #egulations

2.

&riefly des!ribe the 'lan of the 17 th Edition

3.

Identify a #egulation in terms of number identifi!ation system and sear!h for it in the #egulations

4.

E('lain the meanings of some terms used in ele!tri!al installation

).

Identify the symbols used right throughout the wiring #egulations

lessons.

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Introduction In the 're*ious session we learnt that the main legal ena!tment regarding the ele!tri!al installations is the Ele!tri!ity %!t and that under this %!t$ Ele!tri!al Installations must satisfy the IEE "iring #egulations. "hy has the IEE "iring #egulations been s'e!ified+ "hy not some lo!al regulation+ Probably the #egulations of the ,ondon Institution were originally s'e!ified be!ause we were under the &ritish rule at the time of the original -rdinan!e in 1/0. "e !ontinue to use it as our regulation as for one thing drawing u' afresh a regulation of that nature for Sri ,ana is not a feasible 'ro'osition$ for another thing our ele!tri!ity system is based on the &ritish 'attern and finally the IEE "iring #egulations ha*e been drawn u' after !areful thought and 'resently in line with International "iring #egulations.

1.1

2.1

istor! of the I"" wiring regulations

here ha*e been reuirements for safe ele!tri!al wiring as far ba! as 170 and$ in 12$ the So!iety of elegra'h Engineers and Ele!tri!ians$ later to be!ome the Institution of Ele!tri!al Engineers 'rede!essor of IEE 5 now 'art of the IE6$ 'ublished the ‘Rules and Regulations for the Prevention of Fire Risks arising from Electric Lighting’. his first 'ubli!ation of the IEE "iring #egulations was ust a sim'le four8'age do!ument. It was from these small beginnings that the idea of an ins'e!tion body with teeth to 'rote!t the general 'ubli! from the dangers asso!iated with ele!tri!ity use was born. he first edition !o*ered the to'i!s dynamo ma!hine$ the wires$ lam's and danger to 'erson$ as these were the im'ortant to'i!s at that t ime for 'ubli! lighting. "ith time the !ontent and title of the regulations underwent *arious !hanges from edition to edition$ the wor being undertaen by the IEE "iring #egulation 9ommittee. he "iring #egulation 9ommittee are a grou' of members of t he IEE who ser*e as indi*idual e('erts together with re'resentati*es of other 'rofessional institutions$ go*ernment de'artments$ nationali:ed industries and ele!tri!al !ontra!tors and manufa!turers asso!iations. During the early 1)/s$ the ele!tri!ity su''ly industry had begun taing in!reased interest in installation issues$ e*en 5 at one stage 5 'ro'osing re'la!ing the IEE "iring #egulations with a ;9ode of %llied
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%fter about a de!ade$ a modifi!ation@analysis to the 13 th Edition by ?I9EI9 is announ!ed and in 100 the 14th Edition was issued. he metric edition of the same is introdu!ed in early 10. "ith the 'ro'osed laun!h of the 15th Edition in 11 5 more huge !ontro*ersy ensued$ with many arti!les$ news and *iews being aired in the trade 'ress. % maor issue was that of mainland Euro'ean influen!e$ as the 1) th Edition was based in layout on the IE9 "iring #egulations. It should be noted that the two international bodies res'onsible for the 'ubli!ation of IEE wiring regulations 1) th edition are the International Ele!trome!hani!al 9ommission IE96 and the Euro'ean 9ommittee for Ele!tro t e!hni!al standardi:ation 9E?E,E96. hese are *oluntary standards bodies made u' of re'resentati*es of member !ountries. %fter a about another de!ade$ in De!ember 12$ it was announ!ed that im'lementation of the 16th Edition of the IEE "iring #egulations would !ome into effe!t from 1st Aanuary 13. he !o'yright of the 'ubli!ation is held ointly by the IEE and &SI. Subseuently 2//46 se*eral amendments ha*e been made to maintain te!hni!al alignment with 9E?E,E9 harmoni:ation do!ument HD6 su!h asB Identifi!ation of !ondu!tors by !olors or numerals$ safety 'rin!i'les for man8ma!hine interfa!e et!. Cor e(am'le installation !ommen!ing on site after 31 st of
"hat=s in the 17th Edition "iring #egulations+ here are many im'ortant !hanges. he most signifi!ant !hanges !an be summari:ed as followsB % so!et outlet !an now be installed in bathrooms sube!t to being 3m from the edge of a shower or bath and it must be 'rote!ted by a #9D. 

;S'e!ial ,o!ations= su!h as 'hoto*oltai! 'ower su''lies$ fairgrounds and amusement 'ars$ marinas$ e(hibitions and floor and heating systems are now !o*ered. 

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he !ha'ters ha*e now been re8stru!tured and re8numbered for alignment with international standards. 

&elow is an o*er*iew of the history of *arious editions of the IEE wiring regulationsB

12 1st Edition of the "iring #ules issued. Entitled ;#ules and #egulations for the 're*ention of Cire #iss %rising from Ele!tri! ,ighting= !onsisted of a 4 'age do!ument 1

2nd

Edition

17

3rd

Edition Entitled ;eneral #ules re!ommended for "iring for the Su''ly of Ele!tri!al Energy=

1/3

4th

Edition of the IEE "iring #egulations$ !alled ;"iring #ules=

1/7

)th

Edition of the IEE "iring #egulations

111

0th


110

7th


124

th

Edition of the IEE "iring #egulations ;#egulations for the Ele!tri!al Eui'ment of &uildings=

127

th

134

1/th Edition of the IEE "iring #egulations

13

11 th Edition of the IEE "iring #egulations$ #e*ised issue 1436$


re'rinted with minor amendments 14)6$ Su''lement issued 1406$ #e*ised Se!tion 146 1)/

12th

Edition of the IEE "iring #egulations laun!hed$ Su''lement issued 1)46

1))

13th

Edition of the IEE "iring #egulations laun!hed$ #e'rinted$ 1)$ 101$ 102 and 104

100

14th

Edition of the IEE "iring #egulations 'ublished #e'rinted$ 10$ 10$ 1970 (in metric units) $ 172$ 173$ 174 and 170

With the publication of the fifteenth edition it was decided that in future reprints of the same edition (amendments) would be contained in one of five different colored covers red, green, yellow, blue and brown, a new edition would be published when the brown covered reprint required updating. 11

he 1) th Edition of the IEE "iring #egulations laun!hed

13

10th Edition of the IEE "iring #egulations 'ublished

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In about 2//$ 17th Edition of the IEE "iring #egulations !ame into effe!t.

2.2 #lan of the 1$th edition of the I"" wiring regulations 1.2

Sin!e the 17th Edition of the IEE "iring #egulations is the latest guidan!e for designer of ele!tri!al installations$ let us first st udy the layout of the regulations.

Its !ha'ters$ se!tions$ 'arts et! are not numbered in identi!al manner as normal te(tboos so that you may at first get !onfused. ?umbering follows the 'attern of IE90/304. Howe*er$ on!e you understand the 'lan$ sear!hing through the #egulation be!omes uite easy. he #egulations is di*ided into se*en 'arts followed by 10 a''endi!es.

In the numbering system used$ the first digit signifies a Part$ the se!ond digit a 9ha'ter$ the third digit a Se!tion and the subseuent digits the #egulation number.

"e will first see what the 7 'arts are.

Part 1B gives the overriding requirements. hese are the s!o'e$ obe!t and effe!ts$ fundamental 'rin!i'les.

Part 2B gives the underlying definitions. hese gi*e the sense in whi!h !ertain terms are used throughout the #egulations.

he subseuent 'arts gi*e the body of the #egulations. hey areB

Part 3B deals with the identification of the risk or hazard. hese identify the general !hara!teristi!s of the installation$ or 'art of an installation$ that will need to be taen into a!!ount in !hoosing and a''lying the reuirements of the subseuent 'arts.

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Part 4B describes the basic measures of protection against the various risks and the circumstance for which the measures are suitable. hese are for the 'rote!tion of 'ersons$ li*esto!$ and 'ro'erty against the ha:ards that may arise from the use of ele!tri!ity. % modifi!ation to 'rote!tion against *oltage disturban!es and ele!tromagneti! disturban!es are now in!luded in the 17 th edition. % new se!tion has been added$ whi!h deals with measures against ele!tromagneti! disturban!es. Ele!tromagneti! interferen!e E
Part )B deals with the requirements for the selection and erection of equipment.

Prote!tion$ isolation$ swit!hing$ !ontrol and monitoring$ now in!ludes a new se!tion )34 in 17 th edition whi!h deals with the installation of surge 'rote!ti*e de*i!es SPD6. he reuirements of se!tion )34 are for the sele!tion and ere!tion of SPDs for ele!tri!al installations of buildings in order to limit transient o*er *oltages of atmos'heri! origin transmitted *ia the su''ly distribution system and against swit!hing o*er8*oltages. he reuirements are also intended to 'rote!t against transient o*er8*oltages !aused by dire!t lightning stries or lightning stries in the *i!inity of buildings 'rote!ted by a lightning 'rote!tion system. he reuirements do not tae into a!!ount surge 'rote!ti*e !om'onents$ whi!h may be in!or'orated in the a''lian!es !onne!ted to the installations.

Part 0B covers the inspection and testing that is required to be carried out to check that the installation concerned complies with the wiring Regulations.

Part 7B pecial installation or locations Fnder this se!tion identifies the s'e!ial installation lo!ations lie &athrooms$ Swimming Pools$ Hot %ir Saunas$ 9onstru!tion sit es$ %gri!ultural and Horti!ultural ,o!ations$ #estri!ti*e 9ondu!ti*e ,o!ations$ 9ara*an and 9am'ing Pars$
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%''endi!es 181)B Pro*ide tabulated and other ba!ground information reuired by the designer@installer@tester

?ow let us ha*e a loo at the 'lan of 17 th edition of IEE regulations.

Cigure 2.1 shows the im'ortant 'arts$ !ha'ters and se!tions of the Se*enteenth edition. ?umbering follows the 'attern of IE90/304 and 9E?E,E9. ou !an see from the diagram that *arious 'arts$ !ha'ters and se!tions are mentioned$ and that an all8number identifi!ation system is used.

Question If you are reuired to sear!h for #egulation 413.2$ how would you s et about doing it+ "hat do the indi*idual digits mean+

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%iscussion Cirst digit signifies the 'art$ namely 'art 48i.e . protection for safety. "e ha*e to then turn to the !ha'ter referred to by the se!ond digit$ namely !ha'ter 1 of 'art 48i.e. protection against electric shock . "e then ha*e to sele!t the !orres'onding se!tion referred to by the third digit$ namely se!tion 3 of !ha'ter 1 of 'art 48i.e. Prote!ti*e measureB Ele!tri!al Se'aration. he figure following the 'eriod@'oint is the regulation or grou' number$ namely regulation 2 of se!tion 3 of !ha'ter 1 of 'art 4$ whi!h for sim'li!ity is denoted by #egulation 413.2 Cour -ne hree 'oint wo6.

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Cigure 2.2 y'es of 'rote!ti*e !ondu!tors

2.3

%efinitions used in the regulations

%s mentioned in our one of the obe!ti*es$ an integral and essential 'art of the #egulations is that whi!h gi*es the meanings of the terms used$ namely the definitions. "e will state here some of the rele*ant definitions$ while some other will be gi*en later when they a''ear in the te(t.

!gricultural and horticultural "remises# whereB 8 

#ooms$ lo!ations or areas

8

,i*esto! are e't$ or

8

Ceed$ fertili:ers$ *egetable and animal 'rodu!ts are 'rodu!ed$ stored$ or 're'ared 'ro!essed$ or

8

Plants are grown$ su!h as greenhouses.

!m$ient tem"erature# he tem'erature of the air or other medium where the eui'ment is to be used. 

%ack&u" "rotection. Prote!tion whi!h is intended to o'erate when a system fault is not !leared$ or abnormal !ondition not dete!ted$ in the reuired time be!ause of failure or inability of other 'rote!tion to o'erate or failure of the a''ro'riate !ir!uit8breaers6 to tri'. 

% 'art 'ro*iding a defined degree of 'rote!tion against %arrier# !onta!t with li*e 'arts from any usual dire!tion of a!!ess. 

%asic insulation# Insulation a''lied to li*e 'arts to 'ro*ide basi! 'rote!tion and whi!h does not ne!essarily in!lude insulation used e(!lusi*ely for fun!tional 'ur'oses. 

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%asic "rotection# !onditions. 

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Prote!tion against ele!tri! sho! under fault8free

?-EB Cor low *oltage installations$ systems and eui'ment$ basi! 'rote!tion generally !orres'onds to 'rote!tion against dire!t !onta!t$ that is !onta!t of 'ersons or li*esto! with li*e 'arts.

%onding conductor# bonding 

% 'rote!ti*e !ondu!tor 'ro*iding eui'otential

%n assembly of ele!tri!al eui'ment su''lied from the 'ircuit# same origin and 'rote!ted against o*er!urrent by the same 'rote!ti*e de*i!es6. 

'ircuit&$reaker# % de*i!e !a'able of maing$ !arrying and breaing normal load !urrents and also maing and automati!ally breaing$ under 're8 determined !onditions$ abnormal !urrents su!h as short8!ir!uit !urrents. It is usually reuired to o'erate infreuently although some t y'es are suitable for freuent o'eration. 

'ircuit "rotective conductor (c"c)# % 'rote!ti*e !ondu!tor !onne!ting e('osed8!ondu!ti*e8'arts of eui'ment to the main earthing terminal. 

9lass * e+ui"ment# Eui'ment in whi!h 'rote!tion against ele!tri! sho! does not rely on basi! insulation only$ but whi!h in!ludes means for the !onne!tion of e('osed8!ondu!ti*e8'arts to a 'rote!ti*e !ondu!tor in the fi(ed wiring of the installation 

'lass ** e+ui"ment# Eui'ment in whi!h 'rote!tion against ele!tri! sho! does not rely on basi! insulation only$ but in whi!h additional safety 're!autions su!h as su''lementary insulation are 'ro*ided$ there being no 'ro*ision for the !onne!tion of e('osed metal wor of the eui'ment to a 'rote!ti*e !ondu!tor$ and no relian!e u'on 're!autions to be taen in the fi(ed wiring of the installation. 

'onduit# % 'art of a !losed wiring system for !ables in ele!tri!al installations$ allowing them to be drawn in and@or re'la!ed$ but not inserted laterally. 

'onsumer unit (may also be known as a consumer control unit or electricity control unit). % 'arti!ular ty'e of d i s t r i b u t i o n board !om'rising a ty'e8 tested !oordinated assembly for the !ontrol and distribution of ele!tri!al energy$ 'rin!i'ally in domesti! 'remises$ in!or'orating manual means of double8'ole isolation on the in!oming !ir!uits6 and an assembly of one or more fuses$ !ir!uit8breaers$ residual !urrent o'erated de*i!es or signaling and other de*i!es 'ro*en during the ty'e8test of the assembly as suitable for su!h use. 

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'urrent&carr,ing ca"acit, of a conductor. he ma(imum !urrent whi!h !an be !arried by a !ondu!tor under s'e!ified !onditions without its steady8state tem'erature e(!eeding a s'e!ified *alue. 

-esign current. he magnitude of the !urrent rms *alue for a.!.6 to be !arried by the !ir!uit in normal ser*i!e. 

-istri$ution $oard# %n assembly !ontaining swit!hing or 'rote!ti*e de*i!es e.g. fuses$ !ir!uit8breaers$ residual !urrent o'erated de*i!es6 asso!iated with one or more outgoing !ir!uits fed from one or more in!oming !ir!uits$ together with terminals for the neutral and !ir!uit 'rote!ti*e !ondu!tors. It may also in!lude signaling and other !ontrol de*i!es.
Earth. he !ondu!ti*e mass of the earth$ whose ele!tri! 'otential at any 'oint is !on*entionally taen as :ero. 

Earth fault current# %n o*er!urrent l resulting from a fault of negligible im'edan!e between a line !ondu!tor and an e('osed8!ondu!ti*e8'art or a 'rote!ti*e !ondu!tor. 

Earth fault loo" im"edance . he im'edan!e of the earth fault !urrent loo' starting and ending at the 'oint of earth fault his im'edan!e is denoted by 

the symbol Js.

Earth electrode# 9ondu!ti*e 'art$ whi!h may be embedded in the soil or in a s'e!ifi! !ondu!ti*e medium$ e.g. !on!rete or !oe$ in ele!tri!al !onta!t with the Earth. 

Electric .hock . % dangerous 'hysiologi!al effe!t resulting from the 'assing of an ele!tri! !urrent through a human body or li*esto!. 

Electrical E+ui"ment. %ny item for su!h 'ur'ose as generation$ !on*ersion$ transmission$ distribution or utili:ation of ele!tri!al energy$ su!h as ma!hines$ transformers$ a''aratus$ measuring instruments$ 'rote!ti*e de*i!es$ wiring systems$ a!!essories$ a''lian!e and luminaries. 

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Electrical installation# %n assembly of asso!iated ele!tri!al eui'ment ha*ing !oordinated !hara!teristi!s to fulfill s'e!ifi! 'ur'oses. 

E/"osed&'onductive&Part. % 9ondu!ti*e 'art of eui'ment whi!h !an be tou!hed and whi!h is not normally li*e$ but whi!h may be!ome li*e under fault !onditions. 

E/traneous&'onductive&Part % !ondu!ti*e 'art liable to introdu!e a 'otential$ generally earth 'otential$ and not forming 'art of the ele!tri!al installation. 

*solation. % fun!tion intended to !ut off for reasons of safety t h e su''ly from a l l $ or a dis!rete se!tion$ of the installation by se'arating the installation or se!tion from e*ery sour!e of ele!tri!al energy. 

Ele!tri! !urrent in an unwanted !ondu!ti*e 'ath Leakage current# under normal o'erating !onditions. 

Live Part. % !ondu!tor or !ondu!ti*e 'art intended to be energi:ed in normal use$ in!luding a neutral !ondu!tor but$ by !on*ention$ not a PE? !ondu!tor. 

0vercurrent# % !urrent e(!eeding the rated *alue. Cor !ondu!tors the rated *alue is the !urrent8!arrying !a'a!ity. 

0vercurrent detection# % method of establishing that the *alue of !urrent in a !ir!uit e(!eeds a 'redetermined *alue for a s'e!ified length of time. 

0verload current# ele!tri!ally sound 

1)

%n o*er!urrent o!!urring in a !ir!uit whi!h is


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PE conductor % !ondu!tor !ombining the fun!tions of both 'rote!ti*e !ondu!tor and neutral !ondu!tor 

Protective 'onductor# % !ondu!tor used for some measures of 'rote!tion against ele!tri! sho! and intended for !onne!ting together any of the following 'artsB 



8

E('osed !ondu!ti*e 'arts

8

E(traneous !ondu!ti*e 'arts

8

he main earthing terminal

8

Earth ele!trodes6

8

he earthed 'oint of the sour!e$ or an artifi!ial neutral.

Pros"ective fault current I 'f 6.

he *alue of o*er!urrent at a gi*en 'oint

in a !ir!uit resulting from a fault of negligible im'edan!e between li*e !ondu!tors ha*ing a differen!e of 'otential under normal o'erating !onditions$ or between a li*e !ondu!tor and an e('osed8!ondu!ti*e8'art.

Rated current# Galue of !urrent used for s'e!ifi!ation 'ur'oses$ established for a s'e!ified set of o'erating !onditions of a !om'onent$ de*i!e$ eui'ment or system. 

Residual current# %lgebrai! sum of the !urrents in the l i*e !ondu!tors of a !ir!uit at a 'oint in the ele!tri!al installation. 

Residual current device (R'-)# % me!hani!al swit!hing de*i!e or asso!iation of de*i!es intended to !ause the o'ening of the !onta!ts when the residual !urrent attains a gi*en *alue under s'e!ified !onditions. 

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Residual current o"erated circuit&$reaker 2ith integral overcurrent "rotection (R'%0)# % residual !urrent o'erated swit!hing de*i!e designed to 'erform the fun!tions of 'rote!tion against o*erload and@or short8!ir!uit. 

Residual current o"erated circuit&$reaker 2ithout integral % residual !urrent o'erated swit!hing overcurrent "rotection (R''%)# de*i!e not designed to 'erform the fun!tions of 'rote!tion against o*erload and@or short8!ir!uit. 

Residual o"erating current# o'erate under s'e!ified !onditions. 

#esidual !urrent whi!h !auses the #9D to

% !urrent 'assing through the body of a 'erson or .hock current# li*esto! su!h as to !ause ele!tri! sho! and ha*ing !hara!teristi!s liely to !ause dangerous effe!ts. 

.hort&circuit current# %n o*er!urrent resulting from a fault of negligible im'edan!e between li*e !ondu!tors ha*ing a differen!e in 'otential under normal o'erating !onditions. 

.ocket&outlet# % de*i!e$ 'ro*ided with female !onta!ts$ whi!h is intended to be installed with the fi(ed wiring$ and intended to re!ei*e a 'lug. % luminaire tra! system is not regarded as a so!et8outlet system. 



."ur#

% bran!h from a ring or radial final !ir!uit.

Goltage ?ominal 8 Goltage by whi!h an installation or 'art of an installation6 is designated. he following ranges of nominal *oltage r.m.s. *alue for a.!.6 are defined. 

E(tra lowB

17

?ot e(!eeding )/ G a.!. or 12/ G ri''le8free d.!.$ whether between !ondu!tors or to Earth.


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,owB

E(!eeding e(tra8low *oltage but not e(!eeding 1/// G a.!. or 1)// G d.!. between !ondu!tors$ or 0// G a.!. or // G d.!. between !ondu!tors and Earth.

High

?ormally e(!eeding low *oltage.

Cigure 2.2 diagrammati!ally shows the *arious ty'es of 'rote!ti*e !ondu!tors and their use.
1


2

–

The

wiring

Cigure 2.2 y'es of 'rote!ti*e !ondu!tors

2.4

S!mbols used in the regulations

'

rating fa!tor 5 general

'a

rating fa!tor for ambient tem'erature

'c

rating fa!tor for 'rote!ti*e de*i!e or installation !ondition

1

regulations


2

–

The

wiring

regulations

'f

rating fa!tor for higher harmoni! !urrents in line !ondu!tors

'g

rating fa!tor for grou'ing

'i

rating fa!tor for !ondu!tors embedded in thermal insulation

't

rating fa!tor for o'erating tem'erature of !ondu!tor

-e

o*erall !able diameter mm

*$

design !urrent of !ir!uit A

If

fault !urrent A

*n

rated residual o'erating !urrent of the 'rote!ti*e de*i!e in am'eres A

*"f

'ros'e!ti*e fault !urrent A

*t

energy let8through *alue of de*i!e A2s

k

material fa!tor taen from able 43.1

k .

energy withstand of !able A2s

n

number of !ir!uits in a grou'

.

si:e nominal !ross8se!tional area of the !ondu!tor mm2

e

'art of the earth fault loo' im'edan!e whi!h is e(ternal to the installation K

&s

earth fault loop impedance K

2/

ECX4234 Lesson 2

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