***Cont../ Useful Information for Electricians & Apprentices***

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O.S.G.. The use of other methods’ of determining Maximum Demand is Not Precludedwhere Specified by the Installation Designer

FirstlyI make no Apologies for the Way am Writing on any Matters . it can be a first day Apprentice or some one Needing aJog of Memory .
Sowe are all in the Same Boat . “ To Learn “

For the Apprentices . The Day we stop learning is the Day we hang Upour Tool-Bag

CookerDesign Current Calculations

Thefirst thing you have to do is get Your Head around the Calculations !!

(From a Design point of View ) 2392-10

DomesticInstallation Oven(s) & Hob(s) are to be Calculated upon their MAXIMUM LOADING
Startwith a simple Calculation ( An Oven has a rating of 2kW ) 2000

(I = P/V ) Formula … I = 2000 ÷ 230V = 8.70A …. Weare Using the Unit Amps


2392-10/ Domestic Installation Oven(s)

Ovenhas 4 Rings ( 2 x 1kW ) & ( 2 x 1.5kW ) & Grill ( 2kW ) & Oven (3kW )

-Controlled via a CookerSwitch with a Socket outlet .

Asa Designer . we’ll have to Apply Diversity ??

Important )- Diversity allowance to be Applied to the FULL LOAD CURRENT for CookingAppliances .

TheO.S.G. is telling us . Purpose of the Final Circuit fed from theConductors )
O.S.G.Table 1B p/97 – column (3) Cooking Appliances → At the Top of the Page Note : Type ofPremises ( 2392-10 → Household Installations ) Domestic Installation(s)

DomesticInstallation(s) Only O.S.G. - 10A + 30% f.l – Full Load ) of connected Cooking Appliances in the Excess of 10A+ 5A if a socket-outlet is incorporated in the Control Unit . ( C.C.U. ) – 45A + 13A Socket Switched with Neon .

Fromyour point of View ( The First 10A ofthe rated current plus 30% of the reminder ( Plus) 5A if the Control Unit incorporates s Socket.

Calculations)- You bank “ Hold OFF“ the first 10 Amps of the Maximum Load Current )
The10A will be used at the End of the Calculations’

-So your Work out the Total Power Rating & then calculate the Full Load Current

Calculations)- Power = ( 2 x 1 ) + ( 2 x 1.5 ) + ( 2+ 3 ) = 10kW

I= 10000 ÷ 230V = 43.48A … round it up to the first four numbers43.47826087 ( 48 ) 43.48A

UsingDiversity allowance stated ↑↑ ( 43.48A sub 10A = 33.48A )

I= 33.48 x 30 ÷ 100 = 10.04A

Youradding the ( 5A ) for Socket outlet . I = 10A + 10.04 + 5A = 25.04A )- Asa Designer this is your Expected Current Demand .

Remember )- Supply Cables Rated to suit DesignCurrent ( Iz )

 

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First Amendment . p/4

Introduction to BS-7671:2008 .

Note 2 )- Particular attention is drawn to Section 701 . This section now allows socket-outlets (Other than SELV & shaver supply units to BS-EN 61558-2-5 ) to be installedin locations containing a bath or shower ( 3m ) horizontally beyond theboundary of zone 1 .

 

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SWA. ?? Example . :hurray:

□ The Wire Armouring is ( Steel ) & therefore is ( Conductive ) The steel is covered by an Exposed Oversheathof Insulation . So not Exposed .
□ The cable is Terminated on mostinstallation(s) with ( Brass-glands ) which are ( Conductive ) These parts aretherefore ( Exposed conductive parts ) these may also be covered with ( PVC. Shrouds )

“ Function(s) “

TheArmouring is to protect the Cable against ( Mechanical damage ) & to allow the cableto be run out of safe Zone .
TheArmouring is connected to Earth to enable the supply to be ( Automatically disconnected) by the ( Circuit Protective Device ) Underthis Fault Condition(s)

Types of ProtectiveConductor . 543.2. :svengo:

543.2.1. A protectiveconductor may consist of ( One ) or ( More ) of the following .

i) A single-core cable .
ii) A conductor in a cable.
iii) A An insulated or bare conductor in a common enclose withinsulated live conductor(s) .
iv) A fixed bare orinsulated conductor .
v) A metal covering . for example . ( THE sheath . screen orarmouring of a cable )
vi) A metal conduit . metallic cable management system or otherenclosure or electrically continuous support system for conductors .
vii) An (Extraneous-conductive-part ) complying with Regulation 543.2.6.

 

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Defining Protective Conductor . p/32

Protective Conductor isdefined in ( PE ) (BS-7671:2008 ) First Amendment . underPart 2 Definitions as .

A conductor used for some measures of protection against electricshock & intended for connecting together any of the following parts .

- Exposed conductive parts.
- Extraneous conductiveparts .
- The main earthing terminal .
- Earth electrode(s) .
- The earthed point of the source . or an artificial neutral .

 

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Earthing Arrangements for Protective Purposes . 543.6. :svengo:

543.6.1. – Where overcurrent protective devices areused for fault protection . the protective conductor shall be incorporated inthe same wiring system as the live conductors or in their immediate proximity .

 

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134.1.4.p/19 – p/21.
Erection )- Terminating the Cable Ends of S.W.A. cables . :20:

BS-7671:2008. Fundamental requirements set out in Regulation . FirstAmendment / 17[SUP]th[/SUP] Edition

Everyelectrical joint & connection shall be of proper construction as regards Conductance . Insulation. Mechanical strength & Protection .

 

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The most effective way ofTesting for ( Earth Faults) in the wiring or equipment is byMeasuring the Insulation Résistance . as described in Section 6 . 612.3.1.
( Nobreakdown of the Conductor Insulation ) Nails . & Picture hooks . Screws . ???????????? :svengo:

2392-10 .
Floorboards’ Nail driven between the Neutral & Earthconductor(s) creates a ( Neutral to Earth Fault) :hurray:
“ RCD to Trip “
The Fault can be located byInsulation Testing .
Damaged cable must be replaced& either relocated to avoid further damage or protected .

2392-10 :- Requirements to protect cables from Impact& Penetration are given in Regulation 522.6.5. ( v ) p/100 . 522.6.5. the same . ( v ) p/124

 

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Section 712 :

Solar Photovoltaic ( PV ) Power Supply System(s)

712.512 : p/243 Accessibility.

712.513.1. The selection & erection of equipment shall facilitatesafe maintenance & shall notadversely affect provisions made by themanufactures of ( PV ) equipment to enable maintenance or service work to becarried out safely .

Scope .
Section 712 of BS-7671:2008 - ( Applies to the Electrical Installationof ( PV ) power )

Supply systems including system(s) with a.c. modules .

Note )- Section 712 does NOT apply to ( PV )power supply system(s) which are intended for ( Standalone Operation )

New Topics covered . On-Site Guide is Portable Generators .
Two classes of ( TemporaryGenerators ) – (i) Portable Generators .(ii) Mobile Generators .
Generators used for short periods :- One-day & these used for longer timescales .

□ Portable generators with an electrical output rating of up to( 10kVA ) used for small scale work –short term use ( Less than one day )
□ Mobile Generators . used for longer periods & can be in Excess of (( 10kVA ))

• Portable generator used with a Floating Earth .
• Portable generator used without reference to the general mass ofthe Earth .
• Portable generator referenced to the general mass of the Earth .

Permanent use of Generators . Guidance Note 5 - Guidance Note 7 .Section 551 . BS-7671:2008 / 2011 .

Generator(s) are used to ( supply Concession Vehicles ) such as (Burger Vans ) look Section 717 . Mobile & Transportable Units . / GuidanceNote 7 .

Temporarily supply electrical equipment or electricalinstallations with a generator where the mains or usual supply is Unavailable .

Portable generator with Floating Earth :

Small portable generators’ . ranging in ( Output ) from 0.3kVA / 10kVA single phase often have a ( Floating Earth )
Connection of the Socket-outlet of the Unit to the ( Neutral ) of the generator winding.
The ends of the generator winding are brought out to one or more (Three-pin socket-outlet(s) which should conform to BE-EN 60309-2.
[ The Earth socket-tube ofthe socket-outlet(s) are usually connected ( Internally to the Frame of the GeneratorOnly ] ► This arrangement is a form of ( Electrical Separation )

When do NEW INSTALLATIONS have to COMPLY with Amendment No 1 . Requirements
Amendment No 1 July 2011& will come into effect on ( 1 January 2012 ) This means that Installation(s) designedafter ( 1 January 2012 ) will need to comply with the Amendment 1 requirements

An Installation that was designed to the 17[SUP]th[/SUP] Edition “ BEFORE “ 1 January 2012 but gets completed after thisdate should be Certified to the 17[SUP]th[/SUP] Edition

 

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110.2. Exclusions fromScope . :hurray:

First Amendment ( xii )Electric fences covered by BS-EN 60335-2-76 . The rest are thesame . ( i ) - ( xi )

 

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( T ) Testingpurposes :- suitablewarning sign(s) & / or notices shall be provided 2391 / 2392 .

134.1.7. Where necessary forsafety purposes . suitable warning sign(s) & / or notices shall be provided.

134.2. Initial Verification .
During erection & on completion of an installation or anaddition or alteration to an installation . & before it is put into service. appropriate ( Inspection & Testing ) shall be carried out by CompetentPersons to verify that the requirements of this Standard have been met .

Appropriate certification shall be issued in accordance withSection 631 & 632 .

134.2.2. The designer ofthe installation shall make a recommendation for the interval to the firstperiodic inspection & test as detailed in Part 6 .
Note : The requirements of Chapter 34 ( Maintainability ) should be taken into consideration .

135 . Periodic Inspection and Testing .
135.1. It is recommendedthat every electrical installation is subjected to Periodic Inspection andTesting . in accordance with Chapter 62.

Definitions – Part 2 . p/25 .
□ Current-carrying capacityof a conductor .
The maximum current which can be carried by a conductor under specified conditions without its steady-statetemperature exceeding a specified value .

□ Current-using equipment .
Equipment which converts electrical energy into another form ofenergy . such as light . heat or motive power .

 

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Definitions . p/26 . New .to First Amendment

Discrimination : Ability ofa protective device to operate in preference to another protective device inseries .

 

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Definitions . p/26 . change.

Exposed-conductive-part . :carols:
Conductive part of equipment which can be touched & which isnot normally live . but which can become live under fault conditions .

Exposed-conductive-part .
Conductive part of equipment which can be touched & which is notnormally live . but which can become live when basic insulation fails .

 

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UsefulJunk .

17[SUP]th[/SUP] Edition Wiring Regulations . Requirements forElectrical Installations 2008 . :gettree:

The term ( Phase ) is replaced with the term ( Line )

Line is the Internationallyused term . Do Not confuse ( Line ◄ ) conductor with ( Live ◄ )conductor which can be a ( Neutral ) conductor .

Line Conductor )- p/29 . Definitions

A conductor of an A.C. system for the transmission of electricalenergy other than a ( Neutral ) conductor . A protectiveconductor or a ( PEN ) conductor . Theterm also means the equivalent conductor of a D.C. system unless otherwisespecified in the Regulations .

( PEN Conductor ) p/33 . Definitions
A conductor combining the functions of both protective conductor& Neutral conductor .

 

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Portablegenerator referenced to the general mass of the Earth.

Wherethere are ( Extraneous-conductive-parts ) or ( Exposed-conductive-parts ) fromother electrical systems present .
Generatorreference Earthing by means of an (Earth Electrode ) to the general mass of Earth should beinstalled .

NOTE )- That this does NOTcreate a ( TT Arrangement ) Thesupply will be ( TN-S ) from the generator but the ( Neutral ) or (Star point ) will be referenced to thegeneral mass of Earth .

( Generator reference Earthing - Using Earth Electrode )
Wherean Earth Electrode is supplied it will need to be tested by the Standard Method using a (Proprietary Earth Electrode résistance tester )

NOTE )- That an Earth FaultLoop Impedance Tester cannot be used for this Test as the Earth Electrode is NOT used as a meansof Earthing it used to reference the portable generator to the general mass ofthe Earth . As the Earth Electrode isused for referencing & NOT as a means of Earthing . The résistance should .( Ideally be Less than 200Ω )

If buried . generator reference Earthing&/or Bonding conductors should be sized in accordance with Table 54.1. & suitably protected in accordancewith Regulation 543.3.1. Whererestrictions . such as concreted / paved areas or the portable generator isbeing used some distance above ground level . make it impossible to install anEarth Electrode . ( Simultaneously )accessible metal parts . i.e. accessibleExtraneously-conductive-parts or Exposed-conductive-parts from other electrical systems . may beBonded to the ( MAIN ) Earthing Terminal of the generator .

Whereseparate accessible Extraneous-conductive-parts or Exposed-conductive-parts from other electricalsystems are connected together . protective conductors can be sized inaccordance with Regulation 544.1.1.

 

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Importantto Emphasise that Generators must be Used in “ Accordance with the Manufacturers Instructions “ :iagree:

WhereGenerators are ( Hired from plant-hire companies ) it is ( Responsibilityof the plant-hire company ) toprovide the Hirer with Information regarding the Safe use of their Equipment . Underno circumstances should Hirers attempt to change the Internal electricalconnections of Hired Equipment .

Where( Doubt Exists ) as to the Internal Earthing connectionsof the generator . a ( Continuity Testbetween Neutral & Earth socket-tubesat the socket-outlet can be undertaken ) Very Low reading – Less than ( 0.1Ω ) wouldindicate that it is not a generator with ( Floating Earth)

 

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Responsibilitiesof the Duty Holder :carols:

Minor Electrical Installation Work(s) Certificate .
( Requirements for Electrical Installations BS-7671 [[ IET Wiring Regulations ]]

To be Used only for minor electrical work which does NOT includethe provision of a NEW circuit .

System Earthing Arrangement . TN-C-S □ - TN-S □ - TT □
Part 2 )- Installation details . Comments on existing installation . Includingadequacy of ( Earthing & Bonding ) arrangements ( T -&-s ) Regulation 131.8. )
131.8. Moved by BS-7671:2008 Amendment No 1 to 132.16 . ◄ p/393

( T -&-s ) 132.16. p/20 .
Additions & Alterations to anInstallation .

No addition or alteration . temporary orpermanent . shall be made to an existing installation . Unless it has beenascertained that the rating & the CONDITION of any EXISTING EQUIPMENT . including that of the distributor . will beadequate for the altered circumstances . furthermore . the EARTHING & BONDING arrangements . if necessary forthe protective measure applied for the SAFETY of the ADDITION or ALTERATION .shall be adequate .

 

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For Minor Works the Installer is often the Designer of theAddition or Alteration . :svengo:

 

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Definitions – Part 2 : p/31 (NEW ) First Amendment :carolers:

Minor Works .

Additions & Alterations to an installation that do not extendto the provision of a new circuit .

 

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Definitions – Part 2 : p/31 / p/28 :christmaswreath:

From a Inspectors point of View.

Reporting : Communicatingthe results of ( Periodic Inspection& Testing ) of an electricalinstallation to person Ordering the Work .

 

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Standard ( PVC )Insulated Cable(s) are designed to operate at Temperature’s up to ( 70°C ) beyond this there is a risk of Damage . :gettree:

p/340 . Table 4D5 - ( 70°C ) Thermoplastic Insulated & Sheathed flatcable with Protective Conductor - ( Copper Conductors ) T&E .

Cableis guided by two main principles’ .

i)Cable should be able to carry the current load ( Imposed ) on it without ( Overheating )
(( Extreme conditions of temperature it willencounter during its Working Life . ))

ii) You should have sufficient sound Earthing - Limit the voltage to which people areExposed . Safe Level . ( Fault Current to trip MCB inshort time . )

OverCurrents can be Classed into two types

Overload )- An overload occurs when a current flows thatis somewhat to High .
□ Overloadsdon’t normally cause immediate damage . ( The likelihoodof Damage gradually as the duration of the Overload Increases )
□Cables will Overheat & Melt . (Exposing bare conductor(s)

□ DomesticInstallations Overloads usually results from using to many Appliances at the same time . 2392-10

ShortCircuit )-
□ isa connection between Line & Neutral . OR Line & Earth .
Youare looking for a ( Low Résistance ) & thecurrent that can flow may be hundreds or thousands of times to High for thesystem .

Thiscurrent is called the ( FaultCurrent or Short Circuit Current )

Short Circuit Current . An overcurrent resulting from a fault ofnegligible impedance between ( Live Conductors L/N ) having a difference in potential under normaloperating conditions . p/34

Fault Current : A currentresulting from a Fault . p/28

InPractice )- DomesticInstallation(s) Overload protection& Short circuit protection are both provided by the same Device . ( MCB ) or ( RCBO )
Additional Protection . may beprovided by an ( RCD )

Residual Current Operated circuit breaker withIntegral Overcurrent Protection ( RCBO ) designed to perform the functions of protection against Overload & Short Circuit.
“ Resi/ dual “ dual - two - L/N

 

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Circuit Breaker : ( MCB ) Definitions . p/25 - p/21 :17:

A device capable of making . carrying & breaking normal loadcurrents & also making & automatically breaking . under pre-determinedconditions . ( Abnormal Currents )
Such as ( Short Circuit Currents ) . it is usually required to operateinfrequently although some types are suitable for frequent operation .

 

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Just a Reminder : 2392-10 :santa_cheesy:

132.6. Cross-sectional Area of Conductors . ( C.S.A. ) :rant:
:rant:
The Cross-sectional area ofconductors shall be determined for both normal operating conditions & .where appropriate . ( for Fault Conditions according to )

i) The admissible maximum temperature .
ii) The admissible voltage drop . ( Vd )
iii) The electromechanical stresses likely to occur due to ( Short – circuit ) & ( Earth Fault Currents )
iv) Other mechanical stresses to which the ( Conductors ) are likely to be ( Exposed )
v) The maximum ( Impedance ) for correct operation of ( Short Circuit ) & (Earth Fault Protection )
vi) The method of installation .
vii) Harmonics .
viii) Thermal insulation .

 

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The “ Fundamental Principles “

thatare given in Chapter 13 are intended to provide for the safety of persons .livestock & the protection of property against dangers & damage whichmay arise in the reasonable use of electrical installations .

itis recognised that good workmanship by competent persons using proper materialswill reduce any hazards that may arise & that every item of equipment shallcomply with the Appropriate BritishStandard .

Electricaljoints are a potential source of overheating & if NOT securelymade could ultimately cause a fire . for this reason there are severalregulations relating to electrical connections .

Thisis mentioned within Chapter 13 . in regulation 134.1.4. Every electrical joint& connection shall be of proper construction as regards conductance .insulation . mechanical strength & protection .

“Good workmanship by competent persons using the proper materials will reducethe risk of Overheating or Fire . “

 

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Maintenance Free Connections ( 2392-10 )

Junctionboxes are commonly used .

Regulation 526.3.requires that every connection shall be accessible for ( Inspection . Testing & Maintenance )
There are 6 exceptionsto the rule ( vi ) is .

Equipmentcomplying with ( BS-5733) for a ( Maintenance Free ) accessory & ( Marked ) with thesymbol ( MF) & installed in accordance with the Manufactures Instructions .

BS– 5733 . ( Defines ) a Maintenance Free accessory as :-
Anaccessory which does NOT require further ( Inspection . Testing or Maintenance ) afterinstallation in a circuit . & which incorporates ( ScrewlessTerminals ) & cable clamps to secure any associated cables .

TheElectrical Safety Council Technical Manual States that a junction box with Screw Terminals must be ( ACCESSIBLE ) MUSTbe ACCESSIBLE .
Thisis to allow ( Inspection ) of jointswhich could have relaxed or loosened over time . a potential problem withscrewed terminals . SO . unless provision is made for ( Access ) where boarding . carpet or other similar covering is laidover a ( JunctionBox ) it may not be consideredaccessible & maintenance free terminals should be Used .

Appendix15 of the Wiring Regulations which states “ Junction Boxes with Screw Terminals must be Accessible for ( Inspection . Testing & Maintenance ) or Alternatively . use Maintenance Free Terminals / Connection - Regulation 526.3.

“Junction Boxes with Screw Terminals must be Accessible for Inspection …… ETC

Regulation : 526.3. p/106

i) . ii) . iii) . iv) the Same

Regulation : 526.3. p/131 :christmastree1:

v) Joints or connectionsmade in equipment by the manufacturer of the product & not intended to be ( Inspectedor Maintained )

vi) Equipment complyingwith BS-5733 for amaintenance-free-accessory & marked with the symbol ( MF ) & installed in accordance with theManufactures Instructions .

 

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DownlighterJunction box . :svengo:

Whenfitting recessed downlighters the following method would overcome all the issues .

Thesheath of both solid conductors & flexible conductors for the light fittingcan be secured as they enter the Enclosure .
ThisEnables compliance with . Regulation 522.8.5. in particular where it states that thereshall be no ( Undue Mechanical Strain on the Terminations )of the conductor(s)

Regulation 526.8. whichrequires the cores of Sheathed Cables from which the Sheath has been removed tobe Enclosed . can be seen to be complied with .

Cableclamps prevent Strain on Terminations for Compliance with Regulations .

Regulation 522.8.5. p/125 / Regulation 522.8.5. p/101 Thesame

Every cable or conductor shall be supported in such a way that itis not exposed to ( Undue MechanicalStrain ) & so that there is noappreciable mechanical strain on the terminations of the conductors . accountbeing taken of mechanical strain imposed by the supported weight of the cableor conductor itself .

Regulation 526.8. Connectionof multiwire . fine wire & very fine wire conductors .

Regulation 526.8.1. p/107.
In order to avoid inappropriate separation or spreading ofindividual wires of multiwire . fine wire or very fine wire conductors .suitable terminals shall be used or the conductor ends shall be suitablytreated

Regulation 526.9.1. p/131 . Connection of multiwire . fine wire & veryfine wire conductors .
In order to avoid inappropriate separation or spreading ofindividual wires of multiwire . fine wire or very fine wire conductors .suitable terminals shall be used or the conductor ends shall be suitablytreated

Requirements of 17th Edition Wiring Regulations – BS-7671:2008 .

A further potential problem can be found within the ( Junction Box ) concerning the type of conductors that are typicallyterminated . it is often the case in Domestic Installation(s) that solid twin & CPC cables will be used for the fixed wiring withthe conductor to the light fitting . Etc . or transformer if the lighting is ( ELV )
Being a ( Flexible conductor )

Strands of flexible cable are Secured adequately in the terminal& not been damaged to ensure compliance with regulation 526.2.

Asa Tester . How many time have you seen this . ?? . Q - Junctionbox :bulb2:
Whenthe conductor was removed for (Inspection ) it is clear that some ofthe Strands have been damaged during termination .

 

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MaintenanceFree Terminals ,
Theaccess to electrical connections should be adequate for their ( Safe ) &proper ( Inspection) Testing & Maintenance .

Inthis Respect . connections should be in a locationwhere they can reasonably be reached & where there is adequate workingspace . :svengo:

Whereconnections are made in roof spaces & inter-floor spaces the Enclosures containingthe connections should normally be fixed & provision must be made for theiraccess .

Providing )- These TWO CONSTRANINTS are COMPLIED with .Then the continued use of standard circular junction boxes remain ACCEPTABLE . :iagree:

 

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Plain English .

MaintenanceFree Junction Box )- Suitable for use in INACCESSIBLE LOCATIONS . ( MF ) :svengo:

TraditionalJunction Boxes )- Acceptable forLocations which are ACCESSIBLE .

 

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UsefulJunk .

BS-7671 is a British Standard for the “ Requirements for ElectricalInstallations “ it is important torealise that the regulations apply to the “ Design . Erection &Verification of Electrical Installations “

&are NOT intended to be a ( Product Standard ) This is covered at the beginning of thisdocument in Part 1 . Scope :welcome:

Regulation. 113 . Equipment .
113.1. The regulations apply to items of electricalequipment only so far as ( selection& application of the equipment inthe installation are concerned . The regulations Do Not Deal with requirementsfor the construction of assemblies of electrical equipment which are required tocomply with appropriate Standards .

Itis also important to appreciate that BS-7671 does NOTPRECLUDE the use of equipmentthat complies with the appropriate ( Product Standard) regardless of whether the construction of the equipment meets all theRegulations within BS-7671 .

Example.. Etc .
CeilingRose . BS-67 . Etc

Abovehave features which are NOT in accordwith BS-7671 but are ( PERMITTED )by virtue of their compliance to the appropriate ( PRODUCT STANDARD )

 

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The ( Principle) behind the Use of a ( Key or Tool ) is thatit requires a ( DeliberateAct ) to expose the ( LIVE ) conductor(s) . resents2:

 

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Regulation 412.2.2.3. p/62 :20:

Is concerned with ( Ensuring ) thatpersons opening the box do not come into contact with ( Live Parts Unintentionally )

412.2.2.3.
Where a ( Lid or Door ) inan insulating enclosure can be opened without the use of a tool or key . allconductive parts which are accessible if the lid or door is open shall bebehind an insulating barrier ( Providing a degree of protection not less thanIPXXB or IP2X preventing persons from coming unintentionally into contact with thesesconductive parts . This insulatingbarrier shall be ( Removable only by the use of a Tool orKey )

 

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Regulation relating to Junction Boxes is 521.8.3. p/122 . which requires that where ( Two or More ) circuits are terminated in a Single JunctionBox this shall comply with BS-EN 60670-22 :gettree:

Regulation relating to Junction Boxes is 521.8.3. p/98
which requires that where ( Two or More ) circuits are terminated in a Single JunctionBox this shall comply with BS-EN 60670-22 or BS-EN 60947-7.

p/235 . BS-EN 60670-22 . particular requirements forconnecting boxes & enclosures . 521.8.3.
p/236 . BS-EN 60947-7. specification for low-voltage switchgear& control gear . 521.8.3.

 

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Appendix15 ( Informative )

Fig 15A . i) . ii) . iii). the same .
iv) taking account of the total floor area being served . ( As a rule of thumb . a limit of 100m2 has been adopted )

iv) taking account of the total floor area being served . (Historically . a limit of 100m2 has beenadopted ) :20:

 

[Lux]

Hello there every one.

 

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Table of Table(s)

Table 41.1. – Maximum disconnectiontimes .
Table 41.2. – Maximum earthfault loop impedance ( Zs ) for fuses . for 0.4s disconnection time with Uo of 230V.
Table 41.3. – Maximum earthfault loop impedance ( Zs ) for circuit breakers with Uo of 230V .
Table 41.4. – Maximum earthfault loop impedance ( Zs ) for fuses . for 5s disconnection time with Uo of 230V.
Table 41.5. – Maximum earthfault loop impedance ( Zs ) for non-delayed RCDs to BS-EN 61008-1 & BS-EN 61009-1 for Uo of 230V – Regulation 411.5.3.

Regulation 411.5.3. Where an RCD is used for earth faultprotection . the following conditions shall be fulfilled : p/50 Wording

Regulation 411.5.3. Where an RCD is used for fault protection .the following conditions shall be fulfilled : p/57 Wording

Aswith the 17[SUP]th[/SUP] Edition . & First Amendment .

411.5.3. Note 2 : Where (Ra ) is not Known . it may be replaced by ( Zs )

Maximum earth fault loop impedance . ( Zs ) for non-delayed RCDsto BS-EN 61008-1& BS-EN 61009-1. for ( Uo of 230V ◄ ) - Regulation 511.5.3.

With the First Amendment : 41.5.
Rated residual operating current ( mA ) 30 : Maximum earth fault loop impedance ( Zs) ( Ohms ) 1667*
Rated residual operating current ( mA ) 100 : Maximum earth fault loop impedance ( Zs) ( Ohms ) 500*
Rated residual operating current ( mA ) 300 : Maximum earth fault loop impedance ( Zs) ( Ohms ) 167
Rated residual operating current ( mA ) 500 : Maximum earth fault loop impedance ( Zs) ( Ohms ) 100

Aswith the 17[SUP]th[/SUP] Edition . & First Amendment .
Note 2 : The Résistance ofthe installation earth electrode should be as low as practicable a Value exceeding ( 200 ) Ohms may not be stable . Refer Regulation 542.2.4.

 

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UsefulJunk . ( Electricians Judgement . ) :icon_bs:

Whatshould I do if the Manufactures InstallationInstructions for a product ( Conflict ) with the requirements of BS-7671:2008 . or include inappropriate or unnecessary Technical Requirements’

Any Installation Instructions considered tobe Technically Unsound should be ( Queried ) with the Manufacturer & / or referred to the ElectricalContractors registration body for Information .

Yes. I have had this on Site .

 

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Howmuch power does the Individual Built in-oven Draw . Individual Built in-oven – No hob . Supplied with a ( 13A Plug ) BS- 1363 .

Specs/ Regulations e.g. 3kW / 3000W . ( Maximum you can get from 13A Fuse )
Current - ( Amps )
Power– ( Watts ) / (Voltage )

Current ( Amps ) 3000 ÷ 230V = ( Current ( Amps ) 13.04 Amps) Uo /230V
13Aplug & Socket . ( Note :- 0.04 of an Amp over would be took up in Diversity as stated in BS-7671:2008 17[SUP]th[/SUP] Edition. :gettree:

TheDesign of UK Electrical Circuit means that NOT only is every Individual Appliance Protected by a Fuse . ( Protected from Overloading )

BS- 1363 – p/278 . 13A plugs . Socket-outlets . connectionunits & Adaptors .
BS- 1362 – p/278 . Specification. for general purpose fuse links for domestic & similar purposes ( Primarily for usein plugs )

BS- 1362 – During normal flow of Electricity . The fuse (Permits ) the power to pass Unobstructed . Duringan Unsafe Overload . A small piece of Metal Melts . stopping the flow ofElectricity .

Definitions Part 2 / p/28. p/25 The same.

( Fuse ) A device which .by the melting of one or more of its specially designed & proportioned components. Opens the circuit in which it is inserted by breaking the current when thisexceeds a given value for a sufficient time . The fuse comprises all the partsthat form the complete device .

( Fuse element ) A part of a fuse designed to MELT when the fuseoperates .

 

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Appendix 15 ( Informative )

Ring final circuit arrangements .Regulation 433.1..103 .
2392-10 :

The load Current in any part of the circuit should be unlikelyto exceed for long periods the Current –carrying capacity of the cable ( Regulation 433.1.103 refers )
Thiscan generally be achieved . p/425 .

i) Locating socket-outletsto provide reasonable sharing of the Load around the Ring . :svengo:
iv) Taking account of thetotal floor area being served . ( Historically . a limit of 100m[SUP]2[/SUP] has been adopted ) :svengo:

Does the ( R1 + R2 ) Test confirm the correct polarity of a radialcircuit .
NO )- not on it’s Own Whilst the test can provide an Indication ofpolarity . it needs to be combined with Inspection & further Testing asrequired by part 6 - BS-7671:2008 .

January1[SUP]st[/SUP] 2005 Legislation came into effect which broughtElectrical Work in Dwellings under the BuildingRegulations . ( & made it aControlled Service )

ThisAmendment to the Building Regulations .Known as ( Part P ) imposes “ SAFETY “ REQUIREMENTS

ClassifiesElectrical Installation Work – into two basic Categories , ( Notifiable ) & ( Non-notifiable )

 

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BS-1363: Plug there isn’t ( YET ) a regulation to prevent you from plugging itin .

Eachtype of Fuse has a ( Time – current characteristic) which shows the time required to Meltthe Fuse for any given level of Overload Current .
AFuse is a very basic protection device which is destroyed ( i.e. it Blows )

Just a reminder .

Definitions – p/34 .
Résistance Area - ( R[SUP]a[/SUP] ) . ( for an Earth Electrode Only ) The surface area of ground ( around an Earth Electrode) on which a significant voltage gradient may Exit . :rant:

 

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Justmaking you Aware . -&-s . Common Q/As :santa5:

Stationary Equipment . p/35- p/30 .

Electrical Equipment which is either Fixed or whichhas a Mass Exceeding ( 18kg ) & is Not provided with a carrying handle .

 

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Definitions’ )- p/23

Accessory “ Means . a device . other than current-usingequipment . associated with such equipment or with the wiring of an installation.
Appliances “ Means . an item of current using equipment other thana luminaire or an independent motor .


Supplier– see Distributor
Distributor p23 : Aperson who distributes electricity to consumer using electrical lines &equipment that he/she owns or operates .

Origin of an Installation p31 : Theposition at which Electrical Energy is delivered to an Electrical Installation

Wordingfrom a 2392-10 point of View . ( At the Origin ) ▲ :svengo:

Surge Current P/35 : A transientwave appearing as an Overcurrent caused by a ( Lighting Electromagnetic Impulse )

Surge Protective Device (SPD ) P/35
A device that is intended to limit transient overvoltage’s &divert surge Currents .

p/141.Basics )- 534.2.1. Use of ( SPDs )
where required by Section 443 or otherwise specified . SPD shallbe installed .

i) Near the origin of aninstallation . or
ii) In the main distribution assembly nearest the origin of aninstallation .

534.2.3.6. p/145 Co-ordination of SPDs
SPDs shall be selected & erected such as to ensurecoordination in operation .

536.2. Selectivity between overcurrentprotective devices .

Where Selectivity between overcurrent protective devices isnecessary to prevent danger & where required for proper functioning of theinstallation . the manufacture’s instructions shall be taken into account .

536.3 p/148 . Selectivity betweenRCDs .

Where Selectivity between RCDs . is necessary to prevent danger& where required for proper functioning of the installation . the manufacture’sinstructions shall be taken into account .

 

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Abrasion . damage to wiring systems due to : p/437 :christmastree1:

522.6.1.
Impact ( AG ) p/124 .
Wiring systems shall be selected & erected so as to minimizethe damage arising from mechanical stress . e.g. by impact . abrasion .penetration . tension or compression during installation . use or maintenance .

717.52.2. – (ii) p/248. The wiring systemshall be installed using one or more of the following :
ii) Sheathed flexible cablewith thermoplastic or thermosetting insulated to BS-6004. BS-7211 or BS-7919 .if precautionary measures are taken such that no mechanical damage is likely tooccur due to any sharp-edged parts or abrasion .

721.522.7.1. Vibration ( AH) p/255

As the wiring will be subjected to vibration . all wiring shall beprotected against mechanical damage either by location or by enhanced mechanicalprotection . Wiring passing through metalwork shall be protected by means of suitable bushes or grommets . securelyfixed in position . Precautions shall be taken to avoid mechanical damage due to sharp edges or abrasive parts .