***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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Certification& Reporting :

631.2.

Upon completion of theperiodic inspection & testing of an existing installation . an ElectricalInstallation Condition Report . based on the model given in Appendix 6 . shallbe provided . Such documentation shall include details of the extent of theinstallation and limitations of the inspection & testing covered by theReport . together with records of inspection . the results of testing and arecommendation for the interval until the next periodic inspection . :13:

 

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631.3.

Where minor electrical installation work does not include theprovision of a new circuit . a Minor Electrical Installation Work Certificate .based on the model given in Appendix 6 . may be provided for each circuitaltered or extended as an alternative to an Electrical Installation Certificate. :13:

 

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631.4.

Electrical Installation Certificates . Electrical InstallationCondition Reports and Minor Electrical Installation Work Certificates shall becompiled and signed or otherwise authenticated by a competent person or persons. :13:

 

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631.5.

Electrical Installation Certificates . Electrical InstallationCondition Reports and Minor Electrical Installation Works Certificates may beproduced in any durable medium . including written and electronic mediaregardless of the media used for original certificates . reports or theircopies . their authenticity and integrity shall be verified by a reliableprocess or method . The process or method shall also verify that any copy is atrue copy of the original . :13:

 

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560.9. Emergency Lighting Systems .

Emergency Lighting Systems . shall comply with the relevant partof BS-5266 series .

560.10. Fire Detection and Fire Alarm Systems .

Fire Detection and Fire Alarm Systems . shall comply with the relevantpart of BS-5839 series . :13:

 

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Table41.1. .

411.3.2.2.
Themaximum disconnection time stated in Table 41.1 shall be applied to finalcircuits NOT exceeding 32A . :crazy:

Maximum disconnection times . ( No change on number ) 0.4 / 0.2 . Etc .

Bottom . Table 41.1.

Where . in a TT system . disconnection is achieved by anovercurrent protective device and protective equipotential bonding is connectedto all the extraneous-conductive –parts within the installation in accordancewith Regulation 411.3.1.2. the maximum disconnection times applicable toa TN system may be used .

Uo is the nominal a.c. r/ms or d.c. Line voltage to Earth .

Where compliance with this regulation is provided by an RCD . thedisconnection times in accordance with . Table 41.1 relate to prospectiveresidual fault currents significantly higher that the rated residual operatingcurrent of the RCD .

Note : Disconnection is not required for protection againstelectric shock but may be required for other reasons such as protection againstthermal effects .

 

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416.2.4.

Whereit is necessary to remove a barrier or open an enclosure or remove parts ofenclosures . this shall be possible only .

(i) Still the same – 17[SUP]th[/SUP] Edition.
(ii)Still the same – 17[SUP]th[/SUP] Edition .
(iii)Still the same – 17[SUP]th[/SUP] Edition .

Note: This regulation does not apply to :

A ceilingrose complying with BS-67
* A Cord operated switchcomplying with BS-EN 60669-1 . FirstAmendment :sunny:
A bayonetlampholder complying with BS-EN 61184
AnEdison screw lampholder complying with BS-EN 60238.

* A Cord operated switchcomplying with BS-3676 . – 17[SUP]th[/SUP] Edition.

 

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312.3. Deleted by BS-7671:2008 – Amendment no 1 . :sunny:

312.3. :- Type of Earthing Arrangement . 17[SUP]th[/SUP]Edition . 2008

 

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411.4.7. No Change . “ First Amendedment“

Wherea circuit breaker is used to satisfy the requirements of regulation 411.3.2.2 or regulation 411.3.2.3. . Themaximum value of earth fault loop impedance ( Zs ) shall be determined by the formulain regulation 411.4.5 . Alternatively . for a nominal voltage ( Uo ) of 230Vand a disconnection time of ( 0.4s ) in accordance with Regulation 411.3.2.2.or ( 5s ) in accordance with Regulation 411.3.2.3. The values specified intable – 41.3. for the types and ratings of overcurrentdevices listed may be used instead ofCalculation .

 

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BS-1361:1971( 1986 )

Specificationfor cartridge fuses for A.C. circuits indomestic & similar premises .

Replacedby BS-88-3: 2010 and withdrawn 1/3/2010 . First Amendedment

 

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Appendix 1 . ( Normative) :13:

BS-EN 60898:1991 .
Specificationfor circuit-breakers for overcurrent protection for household & similar installations’.
Replacedby BS-EN 60898-1 : 2003 . but remains current .

▪ BS-EN 60898-1 : 2003 . Circuit breakers for A.C. operation .

▪ BS-EN 60898-2 : 2001 . Circuit breakers for A.C. & D.C. operation . BS-EN 60898-2: 2001 . remains current ( it was withdrawn in error and has been reinstated )

 

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Electrical Installation Certificate– Guidance for Recipient ( to be appended to the Certificate ) 17th Edition p- 334 / First Amendedment :13:

ThisCertificate is intended to be issued only for a new electrical installation orfor new work associated with an addition or alteration to an existinginstallation . it should not have been issued for the inspection of an existing electrical installation . An “ ElectricalInstallation Condition Report “should be issued for such an inspection .

 

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First Amendedment : Just a Reminder . :13:

“ Electrical Installation Condition Report “ p-396

Domestic□Commercial □ Industrial □ other ( include brief description )

Extent& Limitations of Inspection & Testing .
Extentof the electrical installation covered by this report . …………………..

Agreedwith : ……..
Operationallimitations including the reasons ( Regulation 634.2. )

( Regulation 634.2. )
Anydamage . deterioration . defects . dangerous conditions and non-compliance withthe requirements of the Regulations . which may give rise to danger . together withany significant limitations of the inspection & testing . including theirreasons . shall be recorded .

Summaryof the Condition of the Installation .
Generalcondition of the installation ( in terms of electrical safety )

… Overall assessment of the installation interms of its suitability for continued use .
SATISFACTOTY/ UNSATISFACTOTY ( delete as appropriate )
*An unsatisfactory assessment indicates that dangerous ( Code C1 ) and / orpotentially dangerous ( Code C2 ) conditions have been identified

Recommendations:
Wherethe overall assessment of the suitability of the installation for continued useabove is stated as UNSATISFACTOTY . I / we recommend that any observationsclassified as “ Danger present “ ( Code C1 ) or potentially dangerous ( Code C2 ) are acted upon as a matter ofurgency .
Investigationwithout delay is recommended for observations identified as “ further investigation required “
Observationsclassified as “ Improvementrecommended “ ( Code C3 ) should be given due consideration .

Oneof the following codes . as appropriate . has been allocated to each of theobservations made above to indicate to the person(s) responsible for theinstallation the degree of urgency for remedial action .

C1 – Danger present . Risk of injury . Immediate remedial actionrequired .
C2 – Potentially dangerous – urgent remedial action required .
C3 – Improvement recommended .

 

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17[SUP]th[/SUP]Edition / FirstAmendedment . :13:

612.2.1. No change .
612.2.2. No change .
612.3. No change .
612.3.1. No change .
612.3.2. No change .
612.3.3. No change .
612.4. No change .
612.4.1. No change .
612.4.2. No change .
612.4.3. No change .
612.4.4. No change .
612.4.5. No change .
612.5. No change .
612.5.1.
612.5.2. Any insulation or insulating arrangement of extraneous -conductive-partsintended to satisfy Regulation 418.1.4. (iii)
(i) when tested at 500V d.c.shall be not less than I megohm . &
(ii) shall be able to withstand a test voltage of at least 2kV a.c. r/ms . &
(iii) shall not pass a leakage current exceeding 1mA in normal conditions of use .

612.6. No change .

612.7. Where the earthingsystem incorporates an earth electrode as part of the installation . theelectrode résistance to Earth shall be measured .
Note : Where a measurement of ( Ra ) is not practicable themeasured value of external earth fault loop impedance may be used .

612.8.No change .
612.8.1.
a) TN- No change .
b) TT- No change .
c) IT- Compliance withRegulation 411.6. shall be verified by calculation or measurement of thecurrent ( Id ) in case of a first fault at the line conductor or at the Neutral.

Note 1 : The measurement is made only if calculation is notpossible because all the parameters are not known . Precautions are to be takenwhile making the measurement in order to avoid the danger due to a double fault.

Where conditions that are similar to conditions of a TT systemoccur . in the event of a second fault in another circuit ( see Regulation411.6.4. (ii)) verification is made as for a TT system ( see point b ) of this regulation .

Where conditions that are similar to conditions of a TN systemoccur . in the event of a second fault in another circuit ( see Regulation411.6.4. (i)) verification is made as for a TN system ( see point a ) of this regulation .

Note 2 : During measurement of the fault loop impedance . it isnecessary to establish a connection of negligible impedance between the neutralpoint of the system and the protective conductor preferably at the origin ofthe installation or . where this is not acceptable . at the point ofmeasurement .

612.9.No change .
612.10.No change .
612.11.No change .
612.12.No change .
612.13.1.No change .
612.14.No change .

 

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860.8. – Wiring Systems . :leaving:

560.8.1. One or more of thefollowing wiring systems shall be utilised for safety services required tooperate in fire conditions .

i) Mineral insulated cable systems complying with BS-EN 60702-1 and BS-EN 60702-2 and BS-EN60332-1-2.
ii) Fire-resistant cables complying with IEC 60331-1 or IEC60331-2 or IEC 60331-3 and with BS-EN 60332-`1-2.
iii) Fire-resistant cables complying with test requirements of BS-EN 50200or BS-8434 or BS-8491 . appropriate for the cable size and with BS-EN60332-1-2.
iv) A wiring system maintaining the necessary fire and mechanicalprotection .

the wiring system selected shall meet the requirements of the relevantcode of practice appropriate to the application and shall be mounted andinstalled in such a way that the circuit integrity will not be impaired during afire .

Note 1 : The codes of practice in the UK for emergency lighting . firealarms and life safety and fire fighting applications are :
i) BS 5266 Part 1 : Fire detection and fire alarm systems forbuildings – Code of practice for system design . installation . commissioningand maintenance .
ii) BS 8519 : Code of practice for the selection and installationof fire-resistant cables and systems for life safety and fire fightingapplications .

Note 2 : BS 5266 . BS 5839 & BS 8519 specifies cables to BS-EN 60702-1. BS 7629-1 & BS 7846 as being suitable when appropriately selected for theapplication .

Note 3 : Examples of a system maintaining the necessary fire andmechanical protection could be :
i) Constructional enclosures to maintain fire and mechanicalprotection . or
ii) Wiring systems in separate fire compartments .

560.8.2. Wiring for control and bus systems of safety servicesshall be in accordance with the same requirements as the wiring which is to beused for the safety services . This does not apply to circuits that do notadversely affect the operation of the safety equipment .

560.8.3. Deleted by BS-7671:2008 . Amendment No 1 & reserved for future use .

560.8.4. Circuits for safety services which can be supplied bydirect current shall be provided with ( Two-pole ) Overcurrent protection mechanisms .

560.8.5. Switchgear & controlgear used for both a.c. & d.c. supply sources shall be suitable for both a.c. &d.c.operation .

650.8.3. Deleted byBS-7671:2008.

The wiring between the safety source and the main distribution boardshall be erected in such a manner as to reduce to a minimum the risk ofShort-circuit or Earth fault or the risk of fire or danger to persons .