***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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“ Overcurrent ” a current flow in a circuit which is ( Greater ) than the ( Rated )current carrying capacity of the cables . :89:

Thiswould normally be due to a Fault on the Circuitor Incorrect Cable .

Ifa ( 20A ) cable protected by a ( 32A ) MCB was loaded by ( 25A) the cable would Overheat & the Device would continue to allow current to flow – This couldDamage the cable . ( Iz)

A Fault Current is a current which is flowing in acircuit due to a Fault ??

A Nail is driven through a cable causing an Earth Fault or a Short-Circuit Fault .
Thiswould cause a ( Very High Current to Flow ) through the circuit . Which must be( Interrupted ) before the Conductor reach a Temperature that could Damagethe Insulation or even the Conductor(s) .

 

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TTSystems .

FinalCircuits that are rated UP to & ( 32A ) require a maximum disconnection time of ( 0.2sec) 41.1.
Distributioncircuit require a maximum disconnection time of ( 1 second ) 411.3.2.4

Ihave not done any TT Systems yet . Am working onit . Amber . ( Youwill get this on 2392-10 ) thisis a start . Yeah :coolgleamA:

 

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Apprentices. → 411.3.2. 1. Final Circuits that are rated UPto & ( 32A ) Look First is it ?? TN- or TT ◄◄ :6:

Apprentices. Look in 41.1→ The Regulations are telling you . - requirea maximum disconnection time of ( 0.2sec ) TT :6:

 

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ElectricShock : ( Earthing comes into Exams a Lot )

Two– Ways in which we can be a risk .

i)Touching Live parts of equipment or system that are intended to be Live .
ii)Touching ( Conductive-parts) which are not meant to be Live . but havebecome Live due to a Fault . ( Basic Insulation Fails )

( Conductive-parts ) associatedwith the second of these can either be ( Metalwork )of Electrical Equipment & Accessories ( Class 1) & that of electrical wiring systems such as ( MetallicConduit ) & ( Trunking ) etc called (Exposed-Conductive-Parts )

orother ( Metalwork ) such as ( Pipes ) ( Radiators) ( Girders ) called ( Extraneous-Conductive-Parts )

17[SUP]TH[/SUP]Edition - P/24
( Extraneous-Conductive-Parts ) A ( Conductive-part) liable to introduce a potential . generally Earth Potential. & not Forming part of the ElectricalInstallation

( Extraneous-Conductive-Parts ) NOT ( Forming part of the Electrical Installation )

17[SUP]TH[/SUP]Edition – p/21
( Class 1 ) Equipment in which protection againstElectric Shock does NOT rely on Basic Insulation Only .

Butwhich includes means for the ( Connection of Exposed-Conductive-Parts ) to a ( ProtectiveConductor ) in the Fixed Wiring of the Installation . BS-EN 61140) :28:

 

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BS-EN 61140 ) Protection against Electric Shock . :28:
Commonaspects for Installation & Equipment requires That :-

• (Hazardous-Live-Parts ) . Shall not beAccessible .
• (Accessible-Conductive-Parts) Shall not be Hazardous-Live when there is ( No Fault or Under – Single FaultConditions )

BS-EN 61140 ) States that those ( ProtectiveMeasures ) providing protection under normal conditions ( That is . When no Faults Exits) provide Basic Protection & those ( Protective Measures ) giving protection Under Single Fault Conditions provide Fault protection– Sec 410 . refers

Themeasures of protection by ( Automatic Disconnection of Supply)

Regulations/ 410.3.3.
- DoubleInsulation .
- ReinforcedInsulation .
-Electrical Separation to Supply to Supply a Single Item of Equipment .
-Extra-Low-Voltage :- SELV . or . PELV . are generally applicable

2392-10. ( Automatic Disconnectionof Supply ) is the MostCommonly Employed method for Electrical Installation(s) .

 

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TheWhys .
- Double & ReinforcedInsulation are more frequently encountered in ( Items)
- Electrical Separation . SELV/ PELV . are only Applied to ( Specific Parts of an Installation)

- Basic/ Protection . ( Protective Earthing )
- Barriers. ( Main Protective Bonding Conductor )
- Enclosures. ( Automatic Disconnectionof Supply ) in the Eventof a Fault .
- Obstacles. ( Automatic Disconnectionof Supply ) for the PrimaryCircuit & connection of ( Exposed-Conductive-Parts ) ofthe Secondary Circuit connected to the ( Protective Conductor ) of the Primary-Circuit ofthe Source .

Point to NOTE : Fictional Extra Low Voltage ( FELV ) ◄◄◄ Equipment so supplied to ( TheProtective Conductor ) -&-s

WhereFictional Extra Low Voltage ( is Employed ) itis necessary to connect the ( Exposed-Conductive-Parts ) ofthe Equipment so supplied to ( The Protective Conductor ) of the Primary Circuit of the Sourcein addition to these Protective Measures required for ( ADS ) Regulation 411.7.3.

Whena Designer ( 2391-10) is considering the Use of ( Obstacles or Placing Out of Reach ) to provide Basic / Protection. it is strongly recommended that careful consideration be given to the ( Statutory Requirements ) relating to :-

• System. work activities & work equipment ( Regulation / 4. of the Electricity at Work Regulation 1989 )
•Insulation . Protection & Placing of Conductors ( Regulation / 7 . of the Electricity at Work Regulation 1989 )
•Work On or Near Live Conductors. ( Regulation / 14 . of the Electricity at WorkRegulation 1989 )
• Earthing . or other suitable precautions . (Regulation / 8 . of the Electricity at Work Regulation1989 )
•Working Space . Access & Lighting . ( Regulation / 15. of the Electricity at Work Regulation 1989 )
•Person to be “ Competent “ to prevent Danger& Injury . ( Regulation / 16 . of the Electricity at Work Regulation 1989 )

►►► Wording /NOT Act . ◄► But . Law . Exams ( Electricity at Work Regulation 1989 )

( Electricityat Work Regulation 1989 ) is ( law ) in the United Kingdom. ◄◄◄ in Exams / Wording is ( LAW )

ConsumerProtection is an ACT ◄◄◄ :75:

( Electricityat Work Regulation 1989 ) Applies to all ElectricalSystems at ( All Voltages )

 

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2391-10- Inspection & Testing: ( Remember two different Words ) Yeah. 2392-10

Inthe case of most Types Electrical Installation there is ( No Statutory Requirement ) to carry out ( Inspection & TestingPeriodically )

Itis . However . A Commonly adopted practice seen as a Means of Meeting the Maintenance“ Obligations “

The. Electricity at Work Regulations 1998. Regulation ( 4 ) & the Housing Act 1985 –Section 11 . BS-7671 is in the Most Part concerned with the Design .Installation . & Initial Inspection & Testing of New Installations

Chapter62 .
Containsa number of Requirements relating to ( Periodic Inspection & Testing ) . Regulation. 622.2. States that ( PeriodicInspection & Testing ) is not required an Effective Management SystemOperated by ( Skilled Persons ) covering itsMaintenance .

However. & as has been Mentioned Previously .
( The Person Responsibly may be Held Accountable in the Event ofan Incident Occurring )

(2391-10 ) Appropriate Records must be Keep of the Maintenance ActivitiesUndertaken . ( Cover ones But . Yeah ) :75:

 

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UsefulJunk .

Ambersof on One .

ImportTerms . that -&-s . will bring up in Exams .

Statutory& Non- Statutory Regulations .
Electrical Systems .
TheBuilding Regulations ( Part P )
Instruments .

2392-10. Firstly .
Foryour Assessor ?? are you aware of the Statutory& Non- Statutory Regulations that are relevant to InstallationWork

Tester. Example . Insulation Résistance.
i)The Range of Instrumentrequired . ≥ 0.5MΩ / 0.1MΩ .
ii)The Requirements regarding the Use & Performance of Test Equipment .

The more you put in the Easier it Becomes . :icon6:

 

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Asan Inspector . You have to consider the Implicationswhen carrying out an Inspection & Testing . ( Of an Installation ) :13:

Inspection& Testing . Certification Required .

InitialVerification .
PeriodicInspection & Testing .

( 2392-10 ) Initial Verification (- New Work & Alterations & Additions . ( TheCertification ( EIC ) Electrical InstallationCertification .
(2391-10 ) Periodic Inspection & Testing . for ExistingInstallations . ( TheCertification ( PIR ) Using Wording – Condition Report . ( PeriodicInspection Report)

►► Both must be accompanied by a ( Schedule of Test Results & Schedule ofInspections ) (EIC ) / ( PIR )

2392-10 – Exams . STATUTORY & NON- STATUTORY REGULATIONS .

Thestatutory regulations the apply to ( Electrical Work) 2392-10 / Initial Verification / NEW INSTALLATIONS . only

Let’skeep the Assessor . Happy . Yeah

TheHeath & Safety at Work . ( ACT ) ◄
TheElectricity at Work Regulation 1989 . ( Law )

2392-10.
The Building Regulation Part / P . ( Domestic Installation ) Yeah (This will guide you back to BS-7671 ) onMatters

BS-7671:2008/ British Standards . Non- Statutory Regulations. ( By using BS-7671 . You are complying with :- ( 2)
TheHeath & Safety at Work . 1974 ( ACT )
TheElectricity at Work Regulation 1989 . ( Law )

2392-10. ( As an Inspector ) -&-swill use the wording ( Inspector / You ) → → → → Not ( Tester ) Fail :grouphug:

 

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Amberof on One again .

ThisForum is here to HELP& Guide you on Matters .

Froman Exam point of View . 2391-10 . ( NotMeggers here )

( Electricityat Work Regulation 1989 ) Wording / Your Test Instrument / Sourceof Energy . Mains- Power / Battery ???

YourTest Instrument ?? Continuity Tester. is a Test on the System in itself . -&-s want to here . “ Continuity Tester “ Etc

2392-10/ Loop Impedance Tester . ( Live Test )

( Electricityat Work Regulation 1989 ) Which requiresan ( External Supply Source ) ≈ ≈ A.C. – becomes part of the System into whichit is Connected .


Point to Note . Here . Amber . :rockon:

Withoutany Thank You . I don’t know if am in the Right Direction . :43:

Pleasehit the ( Like Button ) it does help me OUT. PS. What’s a click on the Button. ( A Lot To Me )

 

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UsefulJunk .

Apprentices(- Earth Fault Current . ??

AnOvercurrent resulting from a ( Fault ) of ( Negligible Impedance ) between a Line Conductor & an ( Exposed-Conductive-Part ) or a ( ProtectiveConductor )

2392-10(- Protective Conductor Current ) “ Meaning “ ( Earth Leakage Current) Deleted / BS-7671:2008 ◄◄ :33:
Acurrent which flows to Earth . or ( Extraneous-Conductive-Parts ) in a circuit which is ( Electrically Sound )

Thiscurrent may have a ( Capacitive Component )including that resulting from the ( Deliberateuse of Capacitors )

17[SUP]th[/SUP]Edition . p/27 .
( Protective Conductor Current ) Electric current appearingin a ( ProtectiveConductor ) . Such as ( Leakage Current )or Electric current resulting from an ( InsulationFault . ) :19:

 

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UsefulJunk .

Tocomply with the Electricity at Work 1989 . & BS-7671:2008.

It is necessary . in appropriate circumstances . Toprovide means to “ Provide “ means to “ Prevent “ any equipment from being Inadvertently or unintentionallyEnergized .

Safe Isolation . ( Padlocking in the Isolated Position )

BS-7671:2008. No VoltageLimitations are Specified . Yeah :19:
Electricityat Work 1989 / Reinforces this ( Regulations apply to all System )

BS-7671:2008. 2392-10 – These are Designed toEncourage Good Practice . Yeah .

 

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Ihave Knocked something Up . in wording .to help you along the Way . Amber . :thinking2:

Thefollowing Test results . States what tests have been performed & which meter has been used .

( Ω) • Low-résistance ohmmeter / Continuitytester .
(MΩ ) • An Insulation résistance tester .
( Ω) • A Loop impedance tester .
(mA ) • A residual current device ( RCD ) tester …….. -&s / GN-3. ( Test instrument should not beoperated for longer than ( 2 seconds )
(kA ) • A prospective fault current ( PFC ) tester .
( Ω) • An earth electrode résistance tester .

• An approved test Lamp orvoltage indicator ……. GS-38
• A Proving Unit …….. ( Thisis an Optional item of Test equipment )

• Insulation Résistance test isthe correct term for this form of testing .

• Loop Impedance tester .
Thisinstrument functions by creating . in effect . an “ EarthFault “ for a brief moment . & is connected to the circuit via a Plug or by “ Flying Leads“ connected separately to Line . Neutral . & Earth.
( The instrument should only allow an Earth Fault to exist for a maximum of ( 40mS ) &resolution of ( 0.01Ω ) is adequate for circuitsup to ( 50A )

• PFC tester .
Normallyone half of a dual loop Impedance ( PFC ) tester . This instrument measures the prospective ( Line – Neutral FaultCurrent )
atthe point of measurement using the same leads as for ( LoopImpedance )

Shouldbe Banned (- “ NeonScrewdriver “ which encourages the passage of Current . at Low-voltage .Through the body .

Proving Unit :

Thisis an Optional item of Test equipment . in thatTest Lamps should be proved on a known Live Supplywhich could . of course be an “ Socket Outlet/ Lighting Point )

TestLamp on such A Known Live Supply may involve entry into “ Encloses “ with the AssociatedHazards

-&-s. Point to Note . TestLamps must be Proved against a ( Voltage Similar ) to that to be Tested . ( 230V.≈ . Lamp ) ??????

 

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BS-7671:2008. requirements .

AnElectrical InstallationCertificate can be issued only by the Installerresponsible for the Installation Work . BS-7671:2008

 

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UsefulJunk .

Asyou Know . Maximum Touch Voltage ( 50V )

TT/ Electrode of 100Ω & RCD of 300mA. What would the Touch Voltage Be???? 100 x 0.3 = 30V - Touch Voltage .