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
-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
Methodsof Inspection & Testing are described in Guidance Note : 3
Wherea . 3-core cable . with cores coloured . Brown . Black . Gary . is used as a switch wire for two – wayor intermediate control . the terminations of the conductors shall beidentified using . [ Brown tape on the . Black & Gray cores ]
2392-10: Inspectors . [ Assessor ] Theneed to comply with the relevant parts of the . Electricity at Work Regulations1989 . Whenreplacing a Or working on a Consumer Unit .
Regulation12 : Means for cutting off the supply& for isolation . Regulation13 : Precautions for work on equipment made [ Dead] Regulation14 : Working on Or near Live conductors .
2392-10: Inspectors Replacinga [CU] in an existing installation is anAddition Or Alteration to that installation .
Therefore: be designed . erected & Verified in accordance with the requirements of the currentedition BS-7671:2011 .
Inspectors Mustnot impair the safety of the installation .Regulations 110.1 ( x ) (x ) External lighting & similar installations . 610.4. Foran Addition or Alteration to an existing installation .it shall be [ Verified ] that the Addition or Alteration complies with the Regulations . & does not impair thesafety of the existing installation .
110.1.1. : Note : “ Premises “ covers the land & allfacilities including buildings belonging to it . 110.1.2. : (vi) Additions& Alterations to the installations & also [ Parts ] of the existinginstallation affected by an Additions& Alterations . 610.4.
Design& Installation . Workshould comply with BS-7671:2011
Part M . of the building regulations must be complied with . Inspection& Testing before taking into service .
BS-7671:2011. does not recognize a kitchen as a special location . PartP does .
TheDomestic Electrical Installation Condition Report . Isused to report on the safety condition of an existing installation in adomestic situation .
2392-10: ( EIC ) is a declaration of Electrical Safety .
(EIC ) is to be issued to confirm that the electrical installation work to whichit relates has been designed .constructed . inspection & tested in accordance with BS-7671:2011 . (EIC ) is to beused only for the Initial Certification of a new installation . Or for an Addition orAlteration to an Existing Installation where new circuits have been [ Introduced ] 2392-10 : ThisCertificate is onlyvalid if accompanied by theSchedule of Inspections & the Scheduleof Test results .
(EICR ) Report is for use when carrying out routine periodic inspection & testingof an existing installation . it is notfor use when Alterations or Additions are made .
DomesticPeriodic Inspection Report . isfor use when carrying out routine periodic inspection & testing of an existinginstallation . it is not for use when Alterations or Additions are made .
a Schedule of Inspections & Schedule of Testresults should accompany the Domestic Periodic Inspection Report .
(MEIWC ) When an Addition to an electrical installation does not Extend to theinstallation of a new circuit .
(PAT Testing - CoP ) Althoughthere is No requirement in the ( EAWR 1989 ) to keep records of equipment & ofinspections & tests . ( HSE 1974 ) Memorandum of Guidance on theseregulations advises that records of maintenance including tests should be keptthroughout the working life of equipment .
Inspection& Testing . & without such records dutyholders cannot be certain that theInspection & Testing have actually been carried out .
ConditionReport Inspection Schedule for (Domestic & Similar Premises with up to 100ASupply ) PeriodicInspection & Testing . Exams
p/400: Regulation –2011 . Note : Thisform is suitable for many types of smaller installation NOT exclusively domestic . 2392-10 ◄◄◄ Wording
2011: Earth electrode for RCDs . ( TT with RCDs ) 2392-10 GN-3: Electrode under test is being used inconjunction with a residual current device the following method of test may be appliedas an alternative to the Earth Electrode résistance test .
Inthese circumstances . Where the electrical resistances to earth are relativelyhigh & precision is NOT required . an Earth Fault LoopImpedance Tester may be Used .
Q) : The test required by regulation to ascertainthat the CPC is correctly connected is called . 612.2.1. Continuityof Protective Conductors . 2392-10
2392-10: Both Online & Practical . must be passedto receive City & Guilds Certification . Practical& Theory assessments . relating tothe Inspection & Testing – of NewInstallation . A Must??
Safeworking . - Isolationpractices . - Use of test equipment . - Inspection& Testing documentation .
if not sure pair up . Testingon the Boards . ►► Make Sure that youfill in the Certificatesfully . :banghead: :13:
CalibrationCertificates . last for a Year . Testinstruments must . therefore . be tested & [ Recalibrated] each year .
Testresults are to be [ Valid ] the instrument must also carry a CalibrationCertificate . This will go onto your Certificates / Model number .
2392-10: -&-s .make no discrimination . on matters . Certification of ElectricalInstallations . being!! Testing & Verification .
Q) The legal responsibilities of an Inspector . Q) The general requirements of BS-7671: relating to Initial Verification . Q) The inspection process & testing requirementsfor New Installation(s)
-&-s. Which [ Certificate ] to use & when & how to usethem . you will get this on your 2392-10 Exam & Practical Assessments . “ On the Boards “ Completionof ( EIC ) certificate details . this is the Important certificate details . Exams & -&-s .
Electrical Installation Certificate - ( EIC) Regulation631.1. requires that .upon completion of the [ Verification] of a New Installation. 2392-10 . Domestic Installation . Domestic electrical work that falls under Part P .Building Regulations .
Or changes to an Existing Installation. GN-3 . shall be provided - Section 632. 632.2 - Uponcompletion of the periodic inspection & testing of an [ Existing Installation ] - ( EICR )
Identification& resolution of common problem .
-&-s. Knowledge necessary to carry outInspection & Testing on New Installations . [ Initial Verification] p/36 . Verification : All measuresby means of which compliance of the electrical installation with the relevantrequirements of BS-7671 are checked . Comprising Inspection . Testing & Certification .
Anyimmediately dangerous condition should preferably be rectified . in not , thedefect should be reported without delay to the employer or responsible employee . Regulation3 of the EAWR .
Regulation3 . places Duties On . Employers. employees & the self-employed . tocomply with the Regulations as far as matters are under their control . Employees. to co-operate with their employer .
Theregulations quantify these responsibilities . by putting them under a legalduty to work in accordance with the requirements of the Regulations .
Definitions: ElectricalEquipment . Includesanything used . intended to be used or installed for use . to generate .provide . transmit . transform . rectify . covert . conduct , distribute .control . store . measure or use electrical energy .
System: Coversall & any electrical equipment which is . or may be . connected to anelectrical energy source . & includes that source .
• Whichof the following IP Codes signifies protection against total immersion inwater: this Q) comes up a lot .
( An “ X “ isused for one of the digits if there is only one class of protection ) Example . Use IPX4 - which addresses moisture résistance only . 2392-10 . [ Each ] digit represents an [ Individual level of Protection ]
IP ] Ingress Protection Rating. X ]which addressesmoisture résistance only 4 ] Protected against splashing water .
2392-10: let’s look at it another way . “ Client’s Need’s “ Imust stress . Emphasising that the “ Client “ as the customer is the main influence of any . [ re-wires ] “ Client “ requirements need tobe satisfied .
411.3.1.1. Protective Earthing . 411.3.1.2. Protective Equipotential Bonding . 411.3.2. Automatic disconnection in a Case of a Fault.
“ Second Digit “ [ IP ] 2 ] Protection against dripping water when tiltedup to 15% . 4 ] Protectedagainst splashing water . 5 ] Protected against water jets . . 6 ] Protected against heavy seas . 7 ] Protected against the effects of - [ Immersion] 8 ] Protectedagainst complete - [ Submersion ]
Definitions. for degrees of protection provided by enclosures of electrical equipment as:
i) Protection of person against access to hazardous parts inside the enclosure . ii)Protection of the equipment inside the enclosure against ingress of solidforeign objects . iii) Protection of the equipment inside theenclosure against harmful effects due to the ingress of water .
Protection Against Overcurrent . Regulation. 131.4.
TheElectricity at Work Regulation 1989 =Part 11 . “ States “ That “ Efficient “ means . suitably located . shall be provided for protecting from “ Excess “ of current every part of the system as may benecessary to prevent danger .
Regulation . Reinforces this . 131.4. States that “ Persons & Livestock “ . shall be protected against injury. & property shall be protectedagainst damage . Due. to excessive temperatures orelectromagnetic stress caused by Overcurrents . likely to arise in Live conductor’s .
2392-10: 131.2.2.. NOTE: Inconnection with fault protection . the application of the method of protectiveequipotential bonding is one of the important principles for Safety .
ProtectionAgainst fault current : Regulation. Reinforces this . 131.4. States that “
TheElectricity at Work Regulation 1989 =Part 5 . “ States “ That “ NoElectrical “ equipment shall be put into use where it’sstrength & capability may be exceededin such a way as may give rise to danger .
Regulation 131.5. Whichrefers to any [ conductor(s) ] being able to carry fault current withoutgiving rise to excessive temperatures . ( inAddition ) Anyitem of electrical equipment intended to carry fault current shall be providedby mechanical protection against electromagnetic stress which could result ininjury or damage to persons . livestockor property . .
-&-s. Q) The connecting of a Mobile Generator ? . this may be achieved by a [ Plug-in-facility ] BS-EN-60309 - Socket p/283: BS-EN-60309 : Plugs . sockets-outlets . & couplers forIndustrial purposes . Table - 54.4. [ 551.4.4.note ]
Regulation p/171: - 551.4.4 . NOTE : for suitable connection arrangements see . BS-EN-60309 - Series .
!!!. Do I Need . An External earth leadconnection to the Generator Star . ??
a. Earthing : p/27
b. Bonding Conductor. : p/23 .A protective conductor providing Equipotential Bonding .
lets Open it Up .
Solution
a. Earthing: connection of the exposed conductive parts of an installation tothe main earthing terminal of that installation. b. Equipotential Bonding . Electrical connectionmaintaining various . exposed-conductive-parts &extraneous-conductive-parts at substantially the same potential .
Wording: “ Meanings “ Twotypes of [ Bonding ] normally used are
• Main protective bonding . & • Supplementary protective bonding . [ where required ]
Main protective bonding – is alwaysrequired . Reasons: Bonding reduces the voltage theremight have been .
[MET ] A terminal block . where Earthing & Bonding conductor(s) are connected together . Etc
Protective Equipotential Bonding – 411.3.1.2. Ineach installation . Main protective bondingconductors . shall connect to the [ MET ] ► Extraneous-conductive-parts including the following . i)Water installation pipes . ii)Gas installation pipes . Etc .
Bonding– the correct title is ‘ Equipotential bonding ’.‘ Electrical connection maintainingvarious exposed-conductive- parts and extraneous-conductive-parts at substantiallythe same potential ’
Ohm’sLaw . Thecurrent in Amperes ( I ) is equal to theelectromotive force . Or Voltage ( V) divided by the Résistance ( R ) inohms .
Current (I) = Voltage (V) / Résistance ( R ) : I =V/R .
CurrentFlow - System voltage & Loadrésistance determine the flow of current. ShortCircuit - Accidental connection createsfault . During a Short-circuit . onlythe résistance of the fault path limits current . Current may increase to manytime’s the load current .
Overloadis defined as an Overcurrent that is confined to the normal current path . “Excessive “ connected loads . ( StalledMotor’s ) Can Overload a circuit . Mostconductors can carry a moderate Overload for a [ Short duration without damage]
Start-upOr Temporary Surge Currents : Motor’s . Transformer’s. Overcurrents protection must be selected that will carry thesecurrents . MCB .
Short-circuitis any current not confined to the Normal path. The “ Term “ comesfrom the fact that such current’s. bypass the normalload . Etc . Short / path around the Load . When a current isGreater than . normal current .
[ Short-circuit’s. ] are usually caused by Accidental contact Or wornInsulation . damage occurs . Facts. [ Moreserious than Overloads ] [ Short-circuit’s. ] include two Or more conductors accidentallytouching . Short-circuit / Fault currents.
Typesof Electrical Fault’s : Overcurrents– can be divided into two categories . Overloads / Short-circuits . Anyelectrical current that “ Exceeds “ therating of the circuit is an “Overcurrent “
Or worn Insulation . damage occurs . ATest that can be take for Granted . youwill get this on your 2392-10 . practical Theimportance of this test . is that you could have damaged your cable duringInstalling it .
632.4. Defects or omissions revealed duringInspection & Testing of the Installation work . Shall be made good beforethe Certificate is issued .
p/31 : Origin of anInstallation : The position at which electrical energy isdelivered to an electrical installation . p/24 : Circuit An assembly of electrical equipment supplied from the same Origin &protected against Overcurrent by thesame Protective device(s)
p/25 . Circuit breakers: . Circuitbreakers : are designed to protectcircuits from Overloads &Short-circuits conditions . When applied within their ratings . MCB. is connected to an electrical circuit& acts as a bridge between the circuit & the power supply . MCBs. are designed to protect electrical circuits from being Overloaded . Calculatea Watt-load for circuit breakers . 10A x 230V = 2300W .
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