***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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Definitions– Part 2 . BS-7671:2008 :17:

Bonding Conductor . p/20 .
Aprotective conductor providing equipotentialbonding .

Class1 Equipment . p/21 .
Whereprotection against electric sock does not rely solely on basic insulation alone. Exposed – conductive parts being connected to a protective conductor whiththe fixed wiring of the installation . (See BS-EN 61140 )

Class11 Equipment . p/21 .
Whereprotection against electric shock relies on the application of additional orsupplementary insulation .

Thereis no provision for the connection of a protective conductorto exposed metalwork .

DoubleInsulation . p/23 .
DoubleInsulation ( Class 11 ) Insulation comprising both basic Insulation &supplementary insulation .

Earth. p/23
Theconductive mass of Earth . whose electricpotential at any point is conventionally taken as Zero. ◄◄

EarthElectrode . p/23
Conductivepart . which may be embedded in the soil or in a specific conductive medium .e.g. concrete or coke . in electrical contact with the Earth .

Aconductor or group of conductors in intimate contact with . & providing anelectrical connection to Earth .

EarthElectrode Résistance . p/23 .
Therésistance of an Earth electrode to Earth .

EarthFault Current .
Anovercurrent resulting from a Fault of negligible impedance between a Lineconductor & an Exposed – conductive – part or a protective conductor .

AFault current which flows to Earth .

EarthFault Loop Impedance . p/23
The impedance of the EarthFault current loop starting & ending at the point of Earth Fault . This impedance isdenoted by the symbol ( Zs )
Symbol( Z ) - Unit ( Ω )

TheEarth Fault Loop .

The impedance of the EarthFault current loop starting & ending at the point of Earth Fault . Consists of :-
• The circuit protective conductor ( C.P.C. )
• Consumers Earthing terminal & Earthingconductor
• for TN – Systems . Themetallic return path .
• for TT – Systems & IT Systems Earth return path .
• The path through the Earthed neutral point ofthe Transformer .
• The Transformer winding & phase conductor to point of Fault .

 

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543-Protective Conductors .

543– provides information on the Selection of “ BOTH “ type & Cross – sectional Area of Protective Conductors .
Protective Conductors . areconductors provided for the purposes of Safety . protectionagainst Electric Shock .

GenericTerm “ ProtectiveConductors “ :thinking2:

 

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2392-10. as designer(s) . Am making you Aware of the Facts .

Cross-sectional Areas of Protective Conductors .

Thereare two Methods that may be Employed when choosing a Protective Conductor asrequired by Regulation 543.1.1.

TheCross- sectional Areas ( C.S.A. ) of every ProtectiveConductor . other than Protective BondingConductors .

MustBe :-

► Selected . in accordance with Regulation 543.1.4. - :icon4:

Or

► Calculated . in accordance with Regulation 543.1.3. - :icon4:

 

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2392-10: Yes we still use it in Industry :icon4:

543.2.7. Earthing Tail Requirement .

WhereMetallic Conduit . Trunking . etc is used for a ProtectiveConductor . The Earthing Terminal ofeach Accessory is required to be connected by a Separate Protective Conductor to the Earthing Terminal incorporated in theassociated box ( Back – Boxes) or other Enclosure .

 

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Fault Protection . “ Simply “

Automatic Disconnection Supply . :icon4:

 

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Applicationsof Earthing : :vanish:

All Metallicenclosures & Extraneous conduciveparts . are at Equipotential .

Functionsof Earthing :

EquipmentEarth : Path for Fault Current . lowertouch voltage . protection against Electric Shock .
LightingEarth : Low résistance path to diversethe current . Under lighting attack .
TelecommEarth : Signal Earth . reduce noise & interference . stabilize D.C. supply voltage & prevent ElectricShock .
ComputersEarth : Reduce interference . maintain supply voltages .

 

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Typeof Earthing :- :vanish:

SupplySystem – Neutral / Earth .
SystemEarth
ElectricalSafety Earth .
LightingEarth .
GeneratorEarth .
ProtectiveEarth . - Surge arrestor .
Telecom/ Computer Earth .
ShieldingEarth .
IntegratedEarthing System -
ElectrostaticEarth – Clean / room – Hospital .

 

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Factors affect to the EarthImpedance . TT Systems

Soil.
Weather.
Electrodetype .
Electrodesize .
Near by Utilities .
Electrode in Parallel . -&-s
Distance between Electrode .

 

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:thinking2:TT Systems

EarthRésistance of an Electrode

Soil Exhibits a resistance to the flow an Electrical Current .
Not an “ Ideal “ conductor
Résistance – can never be Zero . betweenthe Earth Electrode & “ True Earth “
The résistance between the Earth Electrode & “ True Earth “

SoilResistivity in ( Ωm )
Buriedlength of the Electrode in ( m )
Diameter of the Electrode in ( m )

 

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Fault :icon4:

A circuitcondition in which current flows through an abnormal or unintended path .

Thismay result from an Insulation failure or a bridging of Insulation .

Conventionallythe Impedance between Live conductors or between Live conductors & Exposed or Extraneous conductiveparts at the Fault position isconsidered Negligible.

 

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Regulation. Appendix 4 – ( 4D1A ) p/274 :17:

Caremust be taken tie sure that any Conductors’ which is operating above ( 70°C) is terminated into Equipment that canwithstand the higher temperature .
TheBritish Standard only requires that our Equipment is suitable for ( 70°C)

Ambient Temperature mustalways be taken into account .

TheCurrent Carrying Capacities given in the Tables in appendix 4 Calculated for a Cable operating in an Ambient Temperature of ( 30°C ) .

( 4D1A ) for4.0mm[SUP]2[/SUP] – Copper Conductor clipped direct can carry a currentof ( 37A ) at ( 30°C ) Pass a current of ( 37A ) through the conductor it would rise to ( 70°C )

Ambient Temperature were to increase to . ( 40°C ) then theTemperature of the conductor when we passed ( 37A ) through it would rise to ( 80°C )

Side– Effect . of this would be an Increase in Voltage Drop .

• The Maximumpermissible operating temperature of Cables are dependent mainly on the Type ofInsulation Material used in the Cable Construction

( 4D1A )
Ambient Temperature ( 30°C ) ◄◄
ConductorOperating Temperature ( 70°C )

Temperature is the Factor which dictates the size of theConductor in relation to the Number of Circuits Installed.

Thermoplastic : ( 70°C ) :44:

 

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Measurement of ExternalEarth Fault Loop Impedance ( Ze ) iscarried out between the Incoming Line & Protective Earth . :19:
Earthing Conductor Detachedfrom the ( MET ) & test probe clipped toit .

Measurementof the External Earth Fault Loop Impedance ( Ze ) at the Origin of theInstallation for compliance with regulation 612.9

EarthFault Loop Impedance :

Live Tests & great careshould be taken when carrying them out .

Thereare Two Measurements for Earth Loop Impedance .

i) One is for External Loop Impedance ( Ze )
ii) Other is for the Circuit Loop Impedance ( Zs )

Bothof these tests are carried out Using an Earth Fault Loop Impedance TestInstrument with Leads & Probes compliant to ( GS-38 )

(Ze ) Earth Fault Loop Impedance :

TheInstallation must be ( Isolated ) – “ Live Test “ ◄◄ -&-s & the Earthing conductor disconnected .
Connectone Lead to the disconnected Earthing conductor& then insert a Probe into the Terminal ofthe Incoming Line .

TheMeasured Value will be ( Ze )

I use the Megger 1552 : Two Leads .
►► Instrument has ThreeLeads then the Third Lead must be connected to the Incoming Neutral ofthe Supply .

Thisis what -&-s want to Hear . ▼

TheEarthing Conductor must be Reconnected beforere-energising the Supply to the Installation .

 

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(Zs ) Circuit Earth Fault Loop Impedance : :19:

Thisis a Live Test . ◄◄ for-&-s 2392-10 - ( At Socket Outlets)

“ Simple“ What is required . The Instrument is plugged into the Socketusing the Lead supplied & the resultRecorded .

TheHow’s & Why’s ??

Wherethe Circuit has NO socket outlets the instrumenthas to be ( Connected ) to the Exposed Terminalsof the Accessories on the Circuit being Tested .

ALL – POINTS must be tested & the Highest testresult Recorded as ( Zs ) for the Circuit

“ Certification& Reporting “
Onyour Test result sheet & add the Measured ( Ze ) to the Recorded ( R1 + R2 ) value . Then compare the totalvalue with the Measured ( Zs ) if it is Equal toor Lower then all is Fine .

Ifit is Higher then it may be that there is a Loose Connection & further Investigation is required .

Froma Testers point of View (- The Measured value will often be Less than theCalculated value due to the Presence of Parallel Path.

Measured( Zs ) must be compared to the Maximum value of ( Zs )

From-&-s point of View (- Ensurethat it complies with the Requirements for the circuit disconnection time .

 

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O.S.G.p/13 .
BasicInformation Required . 313.1. Beforestarting Work on an Installation . Etc

ForExisting Installations Electricians’ should Satisfy themselves as to the Suitability ofthe Supply including the Earthing Arrangement. :speechless:

 

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Regulations: Table 41.3 - Maximum Earth Fault LoopImpedance ( Zs )

Table 41.3 -For Circuit Breakers with ( Uo ) of 230V . ForInstantaneous operating giving Compliance with the ( 0.4s )disconnection time of Regulation 411.3.2.2.
BS-EN 60898 . / BS-EN 61009-1
MaximumMeasured Earth Fault Loop Impedance ( Ωs ) Overcurrent Protective Device is a Circuit Breaker .

Table 41.1.
MaximumDisconnection Times ( 0.4s ) - 411.3.2.2.
TheMaximum Disconnection Time stated in Table 41.1. shall be applied to FinalCircuit NOT Exceeding ( 32A ) - The regulations are using the Words . Final Circuit(s)

Apprentices. if we look at Table 41.1. - Maximum Disconnection Time stated in Table 41.1.is for a ( TN- system ) A.C. ≈ ( 0.4s )

MaximumEarth Fault Loop Impedance .
TheMaximum Earth Fault Loop Impedance is used to Calculate the available EarthFault Current within an Installation connected at ( Low – Voltage – below 1000V) :17:

 

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EarthFault Loop Impedance .

i) Electrical Earth Fault on a circuitcurrent flows from the Line conductor throughthe Fault . down the CPC.
Alongthe Earthing Conductor provided by the Electricity Company for . TN-S & TN.C.S. or through the EarthElectrode . for a TT System .

ii)The Circuit ( Loop ) then is the Transformers winding ( Impedance )
theSupply Company Line conductor in theInstallation & return Earth conductor ( Résistance )

iii)This Complete Circuit is called the ( Earth Fault Loop) & the ( Earth Fault Loop Impedance ) isthe value in Ohms . Measured

EarthFault Protection for an Electrical Installation .
- Thesupply must have ( One Pole connected to Earth at the Supply Transformer . (Single-Phase ) This creates what is known as a TN- System .
- ( Overcurrent ProtectiveDevice ) MCB . in the Line Conductorwill operate under Earth Fault Conditions provided that enough current flows .

Icant . Stress this Enough .
An“ RCD “ is for . 17[SUP]th[/SUP] Edition / Additional Protection “ Only “ :earmuffs:
433.1. Every Circuit shall be designed so that aSmall Overload of long duration is Unlikely to Occur .

Soif your Earth Fault Path is not good enough to allow sufficient current to flowto operate the MCB . Then you must Install a RCD . :17:

Apprentices:
Electricitytakes the path of Least Résistance . if the path of Least Résistance happens tobe Earth .

EarthElectrode Résistance TT .
The Electrode is the point where the Earth isconnected to Earth .
Measuringthis shows how well the System is connected to Earth . if the Résistance is to High then there is a chance that a Fault will find anEasier Path .

Why’s(- Measuring the Earth Electrode Résistanceshows how good the Earth is & whether it will Work .
EarthRésistance of the Fault Loop Impedance . ifthe Fault Loop Impedance in the Earth Conductor is to Highthen the Current may not rise to a Sufficient Level to cause the MCB to trip inthe Required Time .

 

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Prospective Short Circuit Current -( PSCC )
Thisis the Current you might get if you have a “ ShortCircuit “ in your Supply .

 

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O.S.G. . p/33 - Isolation :46:

Isolating & Switching :

Requirement( Means of Isolation should be Provided. 132.15.1. Every fixed Electric ( Motors ) Etc.

537.1.4.
Atthe Origin of the Installation .
Amain liked switch or Circuit Breaker should beprovided as a Means of Isolation & of Interruptingthe supply on Load.

ForSingle-phase household & similar supplies that may be Operated by UnskilledPersons . A Double - Poledevice must be Used for both TT& TN- Systems .

Fora Three-phase supply to an Installation forming part of a TT System . An Isolator must Interrupt the Line & NeutralConductors . ( DP ) in a TN-S or TN-C-SSystem only the Line Conductors need be Interrupted.

ForEvery Circuit : 537.2.1.1.
Otherthan at the Origin of the Installation . Every Circuit or Group of Circuits thatmay have to be Isolated without Interrupting the Supply to other circuitsshould be provided with its OWN Isolating device. The device must SWITCH all Live conductors . in a TT System & all Lineconductors in a TT System.

Apprentices.
TTSystem & all Line conductors in a TT System
►► Line conductors(s) ( Line & Neutral ) BothLive conductors . -&-s L/N

Asthe Regulation tells Us . p/118 : Isolation .

537.2.Note : Isolation is a “ Function “ intended tomake DEAD for reasons of Safety all or adiscrete section of the Electrical Installations by separating the ElectricalInstallation or Section from Every Source of Electric Energy .

 

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Loop Impedance Testing :

A “ Loop“ in NOT the same as aCircuit . :svengo:
A “ Circuit “ conforms to a Design :hurray:

A Loop may define itself byIncluding Unsuspected Elements where current has found Parallel Paths to Earth .

An Earth Loop determines the Effectiveness of the Protective Device

 

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Prospective Short Circuit Current ( PSCC ) this is theMaximum Short Circuit Current . That could flow in a Event of aFault . It is NecessaryInformation for the Correctsizing of Protective Devices .

The Maximum point of Test for ( PSCC ) is at the Service Entrance . 2392-10
Impedance is best Tested at the Farthest Point from theIncoming Supply .

 

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A “ Circuit “ conformsto a Design . Example :

The Job am on . Wants RCBOs – Only :svengo:

O.S.G. . p/19
Type of Protective Device .
The Consumer Unit ( or DistributionBoard ) ( DB ) containsdevices for the Protection of the Final Circuit . AGAINST

i) Overload - 433.Regulations .
ii) Short – Circuit -434. Regulations .
iii) Earth Fault . 434. Regulations.

Function (i) & (ii) are carried out usually by One Device . Circuit Breaker .
Function (iii) may beCarried out by the CircuitBreaker provided for function (i) & (ii) . or by an RCD .

An RCBO . being a Combined – Circuit Breaker& RCD . Will carry out Functions .(i) – (ii) & (iii) ◄◄ :hurray:

Conforms to a Design . BritishStandards – 2008 :20:

 

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2392-10 : some Revision . :icon_bs:

Prospective Fault Current ( PFC ) is the ►►Highest of the ►► ( PEFC ) & ( PSCC ) ◄◄
it is the Greater of these Two . Prospective Fault Currents . :uhoh2:

Remember the Difference in wording between ( Guidance ) & ( Regulation ) :dots:

O.S.G. 10.2.2. – States . That with the Supply Connected .
i) Check polarity withthe Supply Connected . Using an approved voltage indicator .
ii) Earth Electrode résistanceusing a Loop Impedance tester
GN-3 . p/48 .
Switch OFF Supply before Disconnecting the Earth .
A Loop Impedance tester is connected between the Line conductor at the Source of the TT Installation & the Earth Electrode . & a test performed . The Impedancereading taken is Treated as the Earth Electrode résistance BS-7671:2008 . Ra - I∆n ≤ 50V.
iii) Earth Fault Loop Impedance .
i) GN-3 . p/49 . Toverify that there is an Earth Connection .

iv) Prospective Fault Current Measurement . if not determined by Enquiry of the Distributor .
Prospective Fault Current ( PFC ) is the ►►Highest of the ►► ( PEFC ) & ( PSCC ) ◄◄

GN-3 . p/52
Prospective Fault Current .
Regulation 612.11. requires that the Prospective Fault Current (Ipf ) under both Short-Circuit & Earth Fault Conditions . be Measured . Calculatedor Determined by another method . At the Origin & at other relevant pointsin the Installation .

GN-3 . 434.5.1. States that the Breaking capacity rating of Each Protective Device shallbe NOT Less than the Prospective Fault Currentat its point of Installation
The “ TERM “ Prospective Fault Current “ includes “ the Prospective Short-Circuit Current & the Prospective Earth Fault Current . it is the Greater ofthese Two Prospective Fault Currents . Which should be Determined & Compared with the breaking capacity of the Device .

v) Functional Testing . including RCDs & Switchgear

-&-s : 2392-10 .
As Testers . Sorry “ Inspectors “
On a NEW Installation you Must Not Carry Out Live Tests until you have ( Verified ◄◄ ) the Earth Continuity ◄◄ & Other Dead Tests – “ Polarity “

 

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2392-10 : Calculationsare Great . – But nothing is Gooduntil Proven . :38:

 

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Chapter 61 : p/155 .2392-10

Initial Verification . ( Inspection & Testing ) Two different Words . :icon_bs:

611 – Inspection .
612 – Testing .

 

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2392-10 . ( T ) Some times when you see it written . You get a better Picture . Yeah . Amber . :icon_bs: :uhoh2:


610.1. Every Installation shall . during its Erection& on Completion before beingput into Service . be Inspected & Tested to Verify . as far as is reasonably Practicable . that the requirementsof the Regulations have been met .

610.2. Sections . 131 .311 to 313 & 514.9.1. ( for information required for a Fundament Principles )
610.3. The Verification shall include comparison of the “ Results “ with the relevant criteria to Confirm that therequirements of the Regulations have been Met .
610.4. For an Addition orAlteration to an Existing Installation . it shall be Verified that the Addition or Alteration complies with the Regulations .& does not Impair the Safety of the Existing Installation .

610.5 – The Verification shall be Made by A Competent Person .
610.6. On Completion ofthe Verification .According to Regulations . 610.1. to 610.5. a Certificate orCertificates . shall be Prepared .

Section 611 – Inspection :
611.1. – The Inspection shall procedure Testing & shallnormally done with that part of the InstallationUnder Inspection . ( Disconnected ◄◄ ) from theSupply .

611.2. – The Inspection shall be made to Verify that theInstalled Electrical Equipment is .
In Compliance withSection 511 – This may be Ascertained byMark or be Certification furnished bythe Installer or by the Manufacturer ) &

Correctly selected & erected in Accordance with theRegulations . &

Not Visibly damaged orDefective . so as to Impair Safety .

612 – Testing : ▼▼
The tests of the Regulation 612.2. to 612.13 . Where relevant . Shall be carried Out & theresults compared with the relevant criteria .

612 – Testing : ▼▼ PAGE– 157 . -&-s big time
The tests of Regulation 612.2. to 612.6. . Where relevantshall be carried Out ( in that Order ◄◄ ) before TheInstallation is Energised .

Where the Installation incorporates an Earth Electrode . Thetest of Regulation 612.7. shall also becarried out ( Before ◄◄ ) TheInstallation is Energised .

612 – Testing : ▼▼ PAGE– 157 . -&-s big time .
If any Test Indicates aFailure to comply . that Test . & any preceding tests . The results of whichmay have been Influenced by the Fault has been Rectified .


Chapsplease hit the Thank you Button . I don’t know if you want any more of thisStuff . ???????????? Amber :dots:

 

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What the Regulations Requires -

612.12. Check of Phase Sequence .
For Multi – Phase circuits there is a Requirement to ( Verify ) ThatPhase Sequence is ( Maintained ) :icon_bs:

 

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2392-10 : We use this Dayin Day out . Yeah . “ ConsumerUnit “ :icon_bs:
Section 514 : Identification& Notices .

514.8. – Identification of the Protective Device .
Circuit Protective Devices are required to be Arranged & Identifiedso that the Circuit Protected may be Easily Recognised .

 

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Workingmy why around 17[SUP]th[/SUP] Edition :hurray:

Making you Aware .

538.4. Residual Current Monitor ( RCM )

An– RCM permanently monitors any leakage current . in the downstreamInstallation or part of it . such a device is NOT intended to provide protection against Electric Shock

538.4.1.
InSupply Systems . RCMs may be installed toreduced the risk of operation of the protective device in the event of excessiveleakage current of the Installation or the connected appliances .

The RCM is intended toalert the User of the Installation before the protective device isactivated .

Wherean RCM is installed Upstream of the RCM . it is recommended that the RCM has arated residual operating current . NOT EXCEEDINGa THIRD of that of the RCD

 

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Short Circuit :- Two or more Live conductors touching each other . :svengo:

Evaluation of Thermal Constraints .
Fault current ( I )is found from .

( I ) = Uo / Zs .

Where:
Uo = nominal Line voltageto Earth .
Zs = Calculated value of Loop Impedance .

( I ) = 230 ÷ 0.53 = 434A

 

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Part1 : Fundamental Principles . :6:

Regulation– 132.13 . Documentation for the Electrical Installation.
Requiresthat documentation . required by regulation – 514.9. & part 6 . isprovided for Every Electrical Installation .

Regulation– 134.1.1. Erection & InitialVerification of Electrical Installations .
Requiresthat good workmanship shall beundertaken by Competent Persons & further requires the “ ManufacturesInstructions shall be followed . Etc .

 

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Apprentices: 612 - Testing . Red Book – 2008

Terequired Tests to be for “ Initial Verification“ New /Installation .
Thetests should be carried out in a prescribed Sequence . Some prior to the Circuits being “ Energized “

Tests– Prior tothe installation being “ Energized “ Dead / Testing :6:
612.2.- Continuity of protective conductors .
612.2.2.- Continuity of rind final circuit conductors .
612.3.- Insulation résistance – ( IR )
612.4.- Protection by SELV . PELV . or by electricalseparation
612.4.5.- Basic protection by a barrier or an enclosureprovided during erection . IP2X or IPXXB .or IP4X or IPXXD .
612.5.- Insulation résistance / impedance of floors & walls .
612.6.- Polarity .
612.7.- Earth electrode .

Testsfollowing the Installation being “ Energized “ :6:
612.9.- Protection by AutomaticDisconnection of the Supply- Earth Fault LoopImpedance .
612.10.- Additional protection ( RCDs )
612.11.– Prospective faultcurrent . ( PFC )
612.12.– Check of Phase sequence .
612.13.– Functional testing . – 2392-10 . LastTest to do .
612.14.– Verification of voltage drop . 2392-10- Verification of voltage drop is not normally required during Initial Verification . New / Installation .

 

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Chapter 526 . p/106

Electrical Connections .

526.1 – For every connectionbetween conductors . or between conductor & other equipment shall provide durableelectrical continuity & adequate mechanical strength & provide protection .

 

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Chapter 529 -
Selection& Erection of Wiring System in relation to Maintainability . Including Cleaning . :6:

Threeset of regulations in this section .

529.1– is not Used .
529.2. & 529.3.

 

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Industrial Inspection& Test – Initial Verification :vanish:

EarthLoop Impedance .

( Ze ) = 0.04Ω
TheEarth Fault Loop Impedance ( Zs ) = 0.43Ω

TheEarth Loop Impedance can be calculated before making the equipment live . by adding the ( R1 + R2 ) to the Earth Loop Impedance to the point of Supply .
This would satisfy the First requirement of Regulation 14 –Electricity at Work Regulation 1989 .

“ Which Requires “ There must be good reason for thecircuits to be ( Live ) whilst work is carried out on them .

Working On or Near Live Conductors .
Regulation 14 – Noperson shall be engaged in any work activity on or near any ( Live Conductor) other than one suitably covered with Insulating Material so as to preventDanger . That Danger may arise unless .

a)it is unreasonable in all the circumstances for it to be Dead . &
b)it is reasonable in all the circumstances for him to be at work on or near itwhile it is Live . &
c)suitable precautions ( including where necessary the provision of suitableprotective equipment ) are taken to prevent Injury.

Sanctionfor ( Live ) Functional Checking .

Thesatisfy regulation 14 – You have . Sound SafeSystem of Work
Onlymake circuits ( Live ) wherenecessary . for the Testing . making sure which is Live & which isDead .

Workat a distance if possibly .
Takenecessary precautions .

 

[tomma]

Therésistance of various types of materials are different . for instance . gold isa better conductor of electricity than copper .

Sorry for nitpicking, but isn't copper is a better conductor than gold. Gold is better for using in contacts, as it is more resistant to oxidization. Silver has less resistance than copper.
Thanks for the posts, these are great for revision, and I couldn't resist but to comment, as I thought this myself before I lost the argument. lol

 

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Measuring InsulationRésistance . ( IR ) Motor Testing ( 2.99MΩ )

SubstationMain Board – Main Sub-Board

ControlPanel . - Local Isolator / in ON position “ Phases Disconnected “
Motor Terminals must be Disconnected .

EarthContinuity . Plus ( R1 + R2 ) – CPC Disconnected “ Cross – connected
Linkingeach line conductor to Earth . This will check Polarity as well .

The Polarity of a Three-phase motor is normalchecked by the correction rotation .( 0.11Ω )

 

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EarthFault Loop Impedance . will also need to be measured with the terminals’ disconnected .

To do this Live canbe a little bit awkward . To avoid the complication .The measurements of ( R1 + R2 ) are simply added to the Earth Loop Impedance ofthe Panel & NOTmeasured Live .

Zs = Z panel + ( R1 + R2 )

 

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UsefulJunk .

Megger.

IlluminatedSwitched Probe - SPL 1000 . MFT1502 /1553 only . :43:

TheIlluminated Switched Probe accessory replacesthe RED 4mmtest lead .
Itcan be used anywhere that the 4mm lead set is specified in this user guide . &it will add Extra Résistance to a Loop Test measurement . ◄◄

 

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( EFLI :- Earth Fault LoopImpedance )

BS-7671:2008– Red Cover . 17[SUP]th[/SUP] Awareness

Part7 – Special Installations or Locations .
753– Floor & Ceiling heating systems .

Ifwe look at the Regulations . “ General Requirements“

753.1. Scope .
Thissection applies to the installation of electricFloor & Ceiling heating systems .
Eitherthermal storage or direct heating systems .

Itdoes NOT apply to wall heating or Outdoorheating systems .

YourConcern . The risk is One of penetration of the Element. :35:

 

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EarthFault Loop Impedance . :49:

TheImpedance of the Earth Fault Current Loop starting & ending at the point ofEarth Fault .
ThisImpedance is denoted by ( Zs )
TheEarth Fault Loop comprises the following . starting atthe point of Fault .

- Thecircuit protective conductor .
- Theconsumer’s earthing terminal & earthing conductor
- For. TN Systems . the metallic return path .
- For. TT & IT Systems . the earth return path .
-The path through the earthed neutral point of the transformer .
- Thetransformer winding .
- TheLine conductor from the transformer to the pointof fault .