***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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Are any changes beingmade to the 2392 Fundamental inspection, testing and initial verificationqualification ?
The2392 qualification will be migrating to the QCF in late 2011, with very few changes tocontent or the assessments. More details will be released in autumn 2011.

 

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2392-10:

Protectionagainst Sock .

Provethat the following tables provides ( Instantaneous Disconnection ) for a . BS-EN-type 32A. MCB using tables ( 41.3. – App 3 )
Conformsto :

( Zs ≤ Uo / Ia )

17[SUP]th[/SUP] Edition 2008:2011 )- Table – 41.3. End of the Table . !! ( Type –B . 46/In ) ( Type – C . 23/In ) ( Type – D . 11.5/In )

Zs ≤ 230 ÷160 = 1.44Ω .

( Type – B . 46/In ) ► 46 ÷ 32 = 1.44Ω . Maximum ( Zs ) table 41.2

230÷ 46 = 5 . In . multiplier for instdist .

Min. Amps . for inst . dist (Appendix 3 )

Manufacturesdata show ( 3 – 5 * In ) for instantaneous disconnection .

B. > 3 In . ≤ 5.0 In
C > 5In . ≤ 10.0 In
D > 10 In . ≤ 20.0 In

 

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Protection Against Electric Shock .

Protectionprovided by s Residual Current Device ( TN- systems )
Followingcondition applies . Regulation – 411.5.2.
( Zs x IΔn ≤ 50V )

• ( Zs ) = Earth Fault Loop Impedance in Ohms . Ian= rated residual operating current in Amps .

Protectionin ( TT system )

Theuse of Overcurrent Protective Devices are NOTexcluded . although it is preferred to use a ( RCD) with a disconnection time of NOT greater than ( 1 sec ) 411.3.2.4.

R[SUP]A[/SUP] x Ia ≤ 50V .

Regulation– 411.5.3.

R[SUP]A[/SUP] = sum of all the resistances of earth electrode& protective conductors connected to the Exposed – conductive – parts .
I[SUP]A[/SUP] = the current causing automatic operation of theprotective device with ( 1 sec )

Allowancesfrom Table 41.1. :

411.3.2.3.– TN - systems disconnection time < 5 sec for a . distribution circuits .
411.3.2.4.– TT - systems disconnection time < 1 sec for a . distribution circuits .
Not covered by . 4113.2.2. – ( > 32A circuits )
411.3.2.6.– where disconnection times cannot be met then ( Supplementary Bonding ) must beApplied .

 

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In some Applications where the continuity of service is very high .

“ Hospital “ Operating Rooms . as we can’t accept the tripping of Electricity oncean Earth Fault Occurs .
- Areswhere the Explosions risk is High .

• Omission of Protective devices for SafetyReasons . 2008:2011.

433.3.3. .

Used where unexpected disconnection would cause a dangeroussituation .

i) the exciter circuit of a rotating machine .
ii) the supply circuit of a lifting magnet .
iii) the secondary circuit of a currenttransformer .
iv) a circuit supplying a fire extinguishingdevice .
v) a circuit supplying a safety circuit (fire or gas alarm )

vi) a circuit supplying Medical Equipment used for Life – support in specific Medical Locations’ . where an ( IT ) systems . is incorporated .

 

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aswe know . there are Three- Types ofEarthing Systems in the 2011 .

TN-S.
TN-C-S – ( PME ) .
TT.

Fora ( Low-voltage ) supply given in accordance with the .Electricity Safety . Quality & Continuity Regulations . 2002 .

Deleted by BS-7671:2008 – Amendment . No 1 .

IT) & ( PEN ) is withdrawn .

i) - This is because ( TN-C ) requires an ( Exemption ) from the . Electricity Safety . Quality &Continuity Regulations .
ii) - & ( IT ) system is NOT permitted for a ( Low-voltage ) public supply in the UK. Because thesource is NOT directly Earthed .

 

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(1 ) I split this Question up . of the Net.

Whichone of the following ( Test Readings ) for Continuity of CPC. Would satisfy BS-7671:2011 for a 230V A.C.lighting circuit . ( 0.5Ω )

10MΩ.
100Ω .
1MΩ.
0.5Ω

Calculations’: 230V ÷ 0.5Ω = 460A .

460A )- this is Fault Current would easily disconnect the 6A – MCB .protective device within 0.4 seconds (TN- Earthing system ) Why??

p/301– fig . 3A4 . Type B– BS-EN 60898 .

□ MCB . BS-EN – 60898 .
Rating– ( 6A ) . Current - ( 30A )

□ RCBO is / MCB / RCD
Rating– ( 6A ) . Current - ( 30A )

Overcurrent characteristics of RCBO to BS-EN- 61009-1 : MagneticSettings )- 5 x 6A = 30A . ( Zs < 230 ÷ 30A = 7.67Ω ) table – 41.3 - 6A / 7.67ohms )

( 32A )- RCBO toBS-EN- 61009-1 : Domestic Installation. MagneticSettings )- 5 x 32A = 160A. ( Zs < 230 ÷ 160 = 1.4375 – 1.43. table – 41.3 - 32A / 1.44ohms )

(Zs ≤ 230 / 160 = Zs ≤ 1.43Ω )

-&-s. The maximum ( Zs ) for a BS-EN-60898 . 32A . B type circuit breaker protecting a DomesticRing Final Circuit is . table – 41.3. 1.44Ω .

 

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Witha Spilt –Load . Consumer Unit .

Regulation314. (i) Splitthe Circuit(s)

Downstairslights are on the same RCD as the Upstairs sockets . “ Reason “ forthis is that . if the RCD trips & Downstairs lights go OFF . Downstairs’ sockets are ( Still Live ) the User can plug a tablelamp into One of Them .

 

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Regulations522.6.102. p/125 .

Meansthat such ( Additional RCD Protection ) applies alsoto Lighting circuit(s) . to eliminate the risk of both Lighting circuit(s) . going OFF simultaneously because OFF nuisance tripping .

Each“ Lighting circuit on a Separate RCD.

BathroomLighting Circuit . ( Supplementary equipotential Bonding ) may be Omitted within a Bathroom or Shower .where the conditions of Regulation 701.415.2.are Complied with .
Theseconditions include the requirement that all ( Final circuit(s)within the location have ( Additional protection ) by means of a 30mA– RCD

TheBathroom Lighting Circuit is supplied by means of a Separate Circuit.

Regulations522.6.102.

Where Regulation 522.6.101. applies& the installation is NOT intended to be UNDER the supervision of a ( Skilled or Instructedperson ) a cable installed in accordance withRegulation 522.6.101 – (v) & NOT also complying with Regulation . 522.6.101– (i) . ( ii ) . ( iii ) . or ( iv )

☞ Shall be provided with ( Additional protection ) by means of an ( RCD ) having the characteristics specified inRegulation 415.1.1.

522.6.101 . p/124 .

(iv)– be mechanically protected against damage sufficient to prevent penetration ofthe cable by Nails . Screws & the Likes .

 

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531.5. RCDs in an ( IT )

Whereprotection is provided by an RCD & disconnection following a ( First Fault ) is not envisaged . the Non-operating .residual current of the device shall be at least Equal to the current whichcirculates on the ( First Fault ) toEarth of negligible impedance affecting a Line Conductor .

 

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Socketoutlets . 411.3.3. p/54 .
(i) All socket outlets for general use byOrdinary persons Not Exceeding ( 20A ) .should be protected by a . 30mA – RCD .

Plain English )- p/31. Ordinary Person . A person who is neither a skilled person nor an instructedperson .
TheWording is that socket – outlets with a rated current NotExceed 20A . that are for use by ( Ordinary Persons) & are intended for general use areto be protected .
2392-10. Intended to cover all who dwell in . Houses . Flats . Yeah .

PortableEquipment . see ( Mobile ) p/31 .
(ii) All ( Mobile ) equipment foruse Outdoors should be protected by a . 30mA – RCD . Notexceeding 32A . for use Outdoors .

Mobile equipment ( Portable equipment –( deprecated )) .Electrical equipment which is ( Moved ) while in ( Operation ) or which caneasily be moved from one place to another( while Connectedto the Supply )

SpecialLocations .
Allcircuits in a room with fixed bath or shower should be protected by one or more. 30mA – RCD . shower . lighting . Heater . Ventilation .

( T ) Fundament Principles . 132.13. ( Documents for Electrical Installation(s)
514.9.1. & Part 6. - & whereapplicable . Part 7 . is provided for everyElectrical Installation .

Regulation. 134.1.1. Erection & Initial Verification of ElectricalInstallation(s) requires that goodworkmanship shall be undertaken by ( Competent Person(s) & further requires ( ManufacturesInstruments ) shall be followed .

 

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2392-10: if we reposition a ( Pull – cord ) switch in a location containing abath or shower . Would the circuit need to be RCD protected . YES .
Yesbecause the work would be more than a ( Like – for – like - replacement ) Regulation . 701.411.3.3. .

 

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2392-10.

• Fundamental Principles . ( Scope ) p/14.

(vi ) additions &alterations to installations & also parts of the existing installationaffected by an addition & alteration .

 

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Amendment No 1 . 2011 .

16[SUP]th[/SUP] Edition - Which has renamed Periodic Inspection Reports- ( PIRs ) TO.

ElectricalInstallation Condition Reports – ( EICRs )

UsefulJunk .
Underthe existing arrangements . 2011 . the codes will have a Letter “ C “ for code . in front of them .

2392-10: These reports are also used by placesof work to demonstrate ( Compliance ) with the Electricity at Work Regulations 1989 .

Thetypes of properties that typically fall within the ( EICRs ) guidelines .

BS-7671:2011. Scope . p/14 .

2392-10.
110.1.1. . The regulationsapply to the design . erection & “ Verification “ of electricalinstallations such as those of : E.g.
i)residential premises .
ii)commercial premises .
iv)industrial premises .
vi)prefabricated buildings .

xv) medical locations .

p/36. ( T ) “ Verification “ all measures bymeans of which compliance of the electrical installation with the relevant requirementsof BS-7671:2011 . are checked . comprising . Inspection & Testing &Certification .

 

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ElectricalInstallation Condition Report . ( EICR )

PeriodicInspection is an Inspection on the condition of an ExistingElectrical Installation . To . Prioritiseany deficiencies against BS-7671:2011

Oneway of confirming an ( Existing Electrical Installation ) is safe forcontinued use to have the Installation ( Periodically Inspected & Tested ) & a“ Report “ on the Condition ( Issuedto the personOrdering the Work )

Mustmake this clear . 2392-10 : -&-s . TRIP UP ONE

“ Electrical Installation Condition Report “ is asthe title indicates a “ Report “ NOT a CERTIFICATE . ◄◄ -&-s

( Existing Electrical Installation )
Itrelates to an assessment of the . “ in service condition “ of an Electrical Installation . against therequirements of the Current Edition of BS-7671-2011

-&-s )- the “ Report “ is primarilyfor the benefit of the person ordering the Work .

“ Wording . “ 2391-10 – Exams

Electrical Installation Condition Report Certificate . N/A - NO MARKS :banghead:
Electrical Installation Condition Report .

( Periodic Inspection & Testing) of an Electrical Installation is also ( recommended ) atthe end of the ( Period stated ) on the ( ElectricalInstallation Certificate ) Or .the Last ( ElectricalInstallation Condition Report )

Q/As . -&-s .

An ElectricalInstallation Condition Report . shouldinclude details of the ( Extent of the Installation) &
Any( Limitations of the Inspection & Testing )
The( Reasons for any such Limitations )

The ( Main purpose) of having your Electrical Installation checked is therefore to ( Identify ) so far as is reasonably practicable . & ( Report ) on any factors Impairing or likely to impair the safety of the Electrical Installation .

 

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Visual Condition Report :

Thisreport is intended to be issued only for the purpose of reporting on conditionof an “ Existing Electrical Installation “

Ingeneral a ( VisualCondition Report ) is suitableonly where the Installation has been Inspected & Tested within the last twoyears & the results were reported on an ElectricalInstallation Certificate . Or an Electrical Installation Condition Report .

Note . that a “ Visual ConditionReport “ includes ONLYthe findings of the Inspection of an Electrical Installation .
Note . it does NOTinclude the results of any Electrical Testing.

-&-s: just because I’m paranoid doesn’t meanthey’re not out to get ME .

“ Visual ConditionReport “ isreally a “ Electrical Installation Condition Report “ without the Measurement(s) . :13: Yeah .