Re-take - Useful Information for 2394 :

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Q) . when performing an . earth-fault-loop-impedance-test . thequickest-method of determining-compliance with BS-7671:2008:2011: would be bycomparing the results to . ?
BS-7671:2008:2011:
The . designer-notes
Manufactures-ratings .
A ) . Guidance-note - 3 . Complying

Q) . Ona small-installation-containing . no-distribution-circuit(s) . an insulation-résistance-test can be .
Ignored
Assumed to be correct .
A) . Tested as a whole .
Avoided
A) GN-3 . p.40 .
Simple-installations that contain no-distribution-circuit(s) should preferably be tested as a whole . refer . fig -2.4a

 

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Incorporating Amendment Number - 1: 2012. ( page - 1 )

Mock Exams .

1. The Regulations . ( BS-7671:2008 ) do not apply to ?
a) . Residential-premises
b) . Industrial- premises
c) . Lighting-protection
d) . Street-furniture
part - 1 . 110.2. P.15.

2) . the Regulations do not apply to ?
a) . Offshore-installations
b) . Mines & Quarries
c) . Lift-installations
d) . Low-voltage-generators
part - 1 . 110.1. P14.

3) . Which of the following-documents are deemedNon-Statutory ?
a) . BS-7671:2008:
b) . EAWR . 1989
C) . HASAW . 1974
D) . ESQCR. 2002
part - 1 . 114.1 . p15.

4) . Parts - 3 / 7 . of BS-7671:2008 . are explained inrudimentary terms within ?
a) . Chapter - 13
b) . Chapter - 12
c) . Part - 3
d) . Appendix - 5
part - 1 . 120.3. p16

5) . Basic-protection is defined as ?
a) . Protection against shock under fault-conditions
b) . Protection against electricshock under fault-free-conditions
c) . Protection against contact with. Live-parts underfault free-conditions
d) . Protection against faults . under sound electrical-conditions.
part - 2 . Definitions’ . p.23

6) . Equipment in which protection against .electric-shock does not rely onbasic-insulation only is described as ?
a) . Double-insulated-equipment
b) . Class - 1 . equipment
c) . Class - 11 . equipment
d) . Class - 11 1. equipment
part - 2 . Definitions’ . p.25

8) . A voltage of 250V a.c. ( r/ms ) would be defined as ?
a) . Band - 1
b) . Extra low-voltage
c) . High-voltage
d) . Low-voltage
part - 2 . Definitions’ .

9) . In determining-maximum-demand. Diversity “ may be applies . which is ?
a) . Taking the sum of all the . protective-devices fromany CCU
b) . Taking into account thatnot all loads .will be switched on . at the same-time
c) . Taking into account that all loads . doubtless willbe engaged at the same-time
d) . Ensuring that an economical . and reliable-designpreference is utilised
part - 3 . 311.1 . p.41

10) . Every-installation is divided into circuit(s) inorder to ?
a) . Ensure simplicity of isolation
b) . Comply with European-standards
c) . Avoid hazards andprevent . inconvenience in the event of a fault
d) . Allowindividual-energising of. Circuit(s) which are not isolated
part - 3 . 314.1. p46

11) . A buildingmade entirely out of wood. Would be categorised for External-influence as ?
a) . CA2
b) . CA1
c) . CB3
d) . CB4
Appendix - 5 . p377

12) . The maximum-disconnection-time . for an a.c. . TN - circuitrated at 230v is ?
a) . 0.04 Seconds
b) . 0.1 S
c) . 0.4 S
d) . 0.2 S
part 4 . Table - 41.1 . p53

 

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13) . The maximum ( Zs ) for a BS-EN-60898 . Type - C .circuit-breaker rate at . 16A with a . 0.4 second-disconnection-time is ?
a) . 2.87Ω
b) . 1.44Ω
c) . 0.72Ω
d) . 1.15Ω
part - 4 . maximum ( Zs ) tables - 41.3 . p56

14) . For a TT -system the maximum-earth-fault-loop-impedance for a 100mA . BS-EN-61008-1 . RCD in a 230V circuit is ?
a) . 500Ω
b) . 460Ω
c) . 167Ω
d) . 100Ω
part - 4 . Table - 41.5 . p.57

16) . Where basic-protection is employed in . the form ofa barrier or enclosure . any horizontal-top-surface must meet a protection-level of atleast ?
a) . IPDXX
b) . IP2X
c) . IPXX3
d) . IP4X
PART - 4 . 416.2.2. P67

17) . Except if made from adequate-material . aluminaire-rated at . 200Watts should belocated-away . from combustible-material by
a) . 0.3m
b) . 0.5m
c) . 0.8m
d) . 1.0m
part 4 . 422.3.1 . p74 ……. ( ii) OVER 100 and UP to 300W - 0.8m )

18) . To avoid burning . a non-metallic-part-intended . to betouched but not hand-held cannot exceed ?
a) . 80°C
b) . 85°C
c) . 90°C
d) . 95°C
part - 4 . table - 42.1 p.77

19) . in relation to voltage-disturbances . the résistance of the earthing-arrangement . at the transformer is referred to . within the areaof symbols . as
a) . R[SUP]A [/SUP]
b) . R[SUP] B[/SUP]
c) . R[SUP]D [/SUP]
d) . R[SUP] E[/SUP]
part - 4 . 442.1.2. p89

20) . Every-core ofa cable shall be identifiable at is . terminations and preferably-throughoutits length by ?
a) . Colour-code-only
b) . letter-code-only
c) . number-code-only
d) . one or more of the above
part - 5 .

21) . An appropriate -colour for a . PEN - conductor should be ?
a) . blue-through its length with . green-markings at theterminations
b) . green & yellow -through its length with . blue-markings at theterminations
c) . green & yellow -through its length with . brown-makings at the terminals .
d) . green-through its length with . yellow-markings at the terminals
part - 5 .

22) . A permanent-label with the words . “ Safety-Electrical-Connection - Do Not Remove “ complies with ?
a) . BS-728
b) . BS-1363
c) . BS-951
d) . BS-423
part - 5 .

23) . A cable buried-underground but not in . conduit orducting for mechanical-protection must-incorporate ?
a) . An earthed-armour or metal-sheath or both
b) . A surface-covering of . 50mm thickness-paving-stones
c) . A clear-surface . warning-notice . informing of its location
d) . A PVC - outer-sheath
part -5

24) . The de-rating-factor for a cable surrounded by . 50mm of thermal-insulation is ?
a) . 0.88
b) . 0.78
c) . 0.63
d) . 0.51
part - 5 - table . 52.2 . p.129

25) .In an ( LV - installation ) supplied-directly from a public ( LV) distribution-system themaximum-volt-drop . on a lighting-circuit between the origin . and load-pontshould be no greater than ?
a) . 6% . b) . 5% . c) . 4% . d) . 3% .
part - 5
.

 

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26) .Every-electrical-inspection shall be accessible forinspection . testing and maintenance-purposes . except for which of theflowing ?
a) . A connectionmade in a junction-box. Beneath floorboards
b) . A connectionmade within a . motor-control-unit
c) . A connectiondesigned to . withstand fault-current
d) . A compound-filled or. Encapsulated-joint
part - 5

27) . The rated - RCD -operating-current of such . adevice-installed as a protection againstrisk of fire . in a TT - system shall have a value of ?
a) . 30mA
b) . 100mA
c) . 300mA
d) . 500mA
part - 5

28) . The maximum-prospective-short-circuit-current . or earth-fault-current in. a circuit should not exceed ?
a) . Theoperating-current . of the circuit switching-devices
b) . Therated-breaking-capacity of . any associated-protective-device
c) . Thedesign-current . of any RCD in circuit
d) . Therated-operating-current. Of any RCD in circuit
part - 5

29) . Which of thefollowing. Switching-devices may be satisfactorily-utilised for. The purpose of isolation ? Table - 53.2 .
a) . BS-EN-60669-2-4
b) . BS-EN-60669-2-3
c) . BS-EN-60669-2-1
d) . BS-EN-60669-1
part - 5

30) . When using bare-conductor(s). in extra-low-voltage .lighting-installation(s) supplied from a. safety-isolating-transformer the .minimum-permissible-cross-sectional-area . of conductor(s) must be ?
a) . 1.5mm[SUP]2 [/SUP]
b) . 2.5mm[SUP]2 [/SUP]
c) . 4mm[SUP]2[/SUP]
d) . 6mm[SUP]2 [/SUP]
part - 5

31) . Suspension-devices for. ELV - luminaries must inany-case be capable of supporting atleast ?
a) . 5Kg
b) . 7.5Kg
c) . 10Kg
d) . 20Kg
part - 5

32) . An automatic-electrical-safety-service-supply. Classedas medium-break must. In the event of losing the main-supply. Intake thesafety-services-supply . in a time period of ?
a) . Between 0.15. & 0.5 seconds
b) . Between 0.5. & 5 seconds
c) . between 5. and 15 seconds
d) . Greater than 15 seconds
part - 5

33) . The minimum-value of. Insulation-résistance for a230V. system . must be ?
a) . ≥ 0.25MΩ
b) . ≥ 0.5MΩ
c) . ≥ 1.0MΩ
d) . ≥ 2.0MΩ
part - 6 . Table 61. p.191 . ( Minimum- Values )

34) . Correct polarity must ensure. That every - ESlamp-holder . have their outer orscrewed-contacts-connected . to the neutral-conductor . except for ?
a) . E14. & E27. lamp holders
b) . E14. & BS-EN-60895 . lamp holders
c) . E27. & BS-EN-61009 . lamp holders
d) . E11. & E24. lamp holders
Part - 6. 612.6.p.192

35) . To comply with. Part - 6 of BS-7671: .Periodic-inspection & Testing shallbe. Specifically-undertaken by ?
a) . A formally-qualified. Test-engineer
b) . A person deemed as the “ Duty-holder “ of thecompany carrying out. The work
c) . A expressly-skilled-person
d) . A competent-person.
Part - 6. 621.5. p.195

36) . Zone - 2. of a bathroom is restricted to the .highest-water-outlet. Or the horizontal-plane. Lying abovefinished-floor-level. By ?
a) . 3.00m
b) . 2.50m
c) . 2.25m
d) . 2.00m
Part - 6. p.202

 

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37) . In zone - 3. of sauna-equipment must be able towithstand a minimum-temperatureof ?
a) . 100°C
b) . 120°C
c) . 125°C
d) . 170°C
part - 7. 703.512.2. (iii) p.213

38) . A marinas-equipment installed above a jetty. Or wharf.Which is likely to encounter-water-jets . shall be selected to comply with. External-influence-levelsof ?
a) . ( AD4 ) : IPX4
b) . ( AD5 ) : IPX5
c) . ( AD6 ) : IPX6
d) . ( AE6 ) : IPX5
part - 7 . 709.512.2.1.1. (ii) p.226

39) . For a BS-88-2.2. fuse rated at . 25A . to obtain a .0.4s - disconnection-time . it would require aminimum-prospective-fault-current of ?
a) . 160A
b) . 130A
c) . 100A
d) . 85A
Appendix - 3. Time / current - graph . p.299 . ( E & G )

40) . A 30 Amp .Semi-enclosed. BS-3036 fuse . receiving a prospective-fault-current of 210A ? ( C f - 1.45. 1.45 ÷ 2 = 0.725 )
a) . 5.0 . seconds
b) . 1.0 . seconds
c) . 0.4 . seconds
d) . 0.2 . seconds
Appendix - 3. Time / current - graph . p.297 . ( E & G )

 

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1) . A building-constructed solely of wood . would have an. External-categoryof ?
a) . CA2
b) . CA1
c) . CA3
d) . CA4
Appendix - 5 .p.377

2) . As. BS-7671:is .
a) . Documentdesigned solely. For the use of electricians
b) . legal-documentused . in a court of law
c) . Non-statutory-document
d) . Statutory-document
114.1. p.15 .. ( The Regulations are Non-statutory )

3) . The fundamental-principles of. BS-7671: covering the. protection against voltage-disturbances . etc States - that the installation shall have anadequate-level of immunity against ?
a) . motors-running
b) . the operationof circuit-breakers
c) . atmospheric-events
d) . voltage-recovery
131.1. p.16

4) . Thefundamental-principles of. BS-7671: covering the . protection against voltage-disturbances. etc States - that the installationshall have an adequate-level of immunityagainst ?
a) . the weather
b) . electromagnetic-disturbances
c) . voltage-loss
d) . vibration
131.1. p.16

5) . what is themaximum ( Zs ) for a 10A . type- Ccircuit-breaker protecting a . standard-discharge type-lighting-circuit ?
a) . 1.15 Ω
b) . 2.30 Ω
c) . 1.44 Ω
d) . 1.92 Ω
table - 41.3 . p.56

6) . A double-insulated. Hand-heldelectric-drilling-machine is knownas ?
a) . Class - 11 equipment
b) . A DeWat
c) . Class HI equipment
d) . Class - 1 equipment
Definition . p 25

7) . An Electrical-Installation-Certificate should be signed by ?
a) . thelocal-authority
b) . A competent-person
c) . The customer
d) . The DNO
Appendix - 6 . p389

8) . When considering-external-influences . the code ( AD4 ) requires . IP - rated-equipment to ?
a) . IPXO
b) . IPX1
c) . IPX4
d) . IPX5
Appendix - 5 . p381

9) . The external-influence-code . ( AD1 ) requires. IP - rated-equipment to ?
a) . IPX4
b) . IPX1
c) . IPX0
d) . IPX2
Appendix - 5 . p381

10) . When considering-external-influences. the code ( AA5 ) relates to the . ambient-temperature-range ?
a) . ( - 5°C to +45°C )
b) . ( - 60°C to +5°C )
c) . ( +5°C to +40°C ) ***
d) . ( -25°C to 0°C )
Appendix - 5 . p378

11) . When considering-external-influences. the code ( AA1 ) relates to the . ambient-temperature-range ?
a) . ( - 5°C to +45°C )
b) . ( - 60°C to +5°C ) ***
c) . ( +5°C to +40°C )
d) . ( -25°C to 0°C )
Appendix - 5 . p378

12) . Electrical-installationsshall . be divided into-circuits to ?
a) . allow easier-access to the installation
b) . allowmore-even . distribution of power
c) . allow for expansion without . changing the maximum-demand
d) . reduce-electromagnetic-interference
314. 1 . ( v ) p.46

13) . One method of determining the . external-loop-impedance . istaking a reading at ?
a) . The origin of supply
b) . The supply and. furthest-outlet
c) . The supply and subtracting the values of ( R[SUP]1[/SUP] + R[SUP]2[/SUP] )
d) . thefurthest-outlet from the supply-origin
O.S.G. 10.3.6. P.101

 

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Q) . Single-phase-circuit . using 2.5mm[SUP]2 [/SUP] - single-corepvc -cables in conduit . supplies a design-current of 20A . if the cables are .15m - long and have a rated-voltage-dropof . 18mV / A / m . theactual-voltage-drop . will be
a) . 2.5V
b) . 5.4V
c) . 6V
d) . 16.6V
( 18mV/A/m . x . 20A x 15m ) ÷ 1000 = 5.4V . 18 x 20 x 15 = 5400 . ÷ 1000 = 5.4V

 

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Q) . A protective-conductor connecting the .main-earthing-terminal of an installation to an . earth-electrode or to other means of earthing iscalled .
a) . Main-protective-conductor
b) . Earth-continuity-conductor
c) . Circuit-protective-conductor
d). Earthing-conductor.

Q) . When carrying out an. Inspection of anew-installation . its not necessary to verify the ?
a) . Total . earth-fault-loop-impedance for each-circuit
b) . Connection ofconductors
c) . Methods of protection. against electric-shock
d) . Presence ofdiagrams. Instructions and similar-information .

Q) . Certain information must be . made available topersons carrying out inspection & testing. Of an installation before thetesting-commences . One such-item ofinformation would be ?
a) . Name of theclient
b) . Name of theperson who. Designed the installation
c) . Length ofcable-runs . in the installation
d) . Any circuit orequipment. Vulnerable to a typical-test

Q) . When carrying out a. visual-inspection of anelectrical-installation. Which one of the following does. Not have to beverified ?
a) . The method ofprotection. against electric-shock
b) . The electricity-supplier
c) . Connection of conductors
d) . Presence ofundervoltages-protective-devices

Q) . When an addition is made to an. Existing-installation.The contractor shall record on the . Electrical-Installation-Certificate . orthe Minor-Electrical-Installation-works-certificate any ?
a) . Changes inownership
b) . Records ofrepair over. the last five-years
c) . Defects in the existing-installation
d) . Voltage-dropin the longest-circuit

Q) . An insulation-résistance-test. Is to be carried outon a . 3 - phase 400V circuit . thetest-voltage and minimum-acceptable-reading would be ?
a) . 250V .d.c. & 0.5MΩ
b) . 500V .d.c. & 0.5MΩ
c) . 500V . d.c. & 1MΩ . for the sake of. Chief-examiners report .
d) . 800V .d.c. & 0.5MΩ .

Q) . If an area within an installation. Undergoes a ( 10°C ) rise in ambient-temperature . the effect on thecurrent-carrying-capacity of cables will be to ?
a) . Decrease the value of ( Iz )
b) . Increase thevalue of ( Iz )
c) . Leave ( Iz )unchanged
d) . Increase thefault-current by . 10 - per cent

Q) . For protection against overvoltage a . 230Velectricity-meter should have an impulse withstand of ?
a) . 6kV
b) . 4kV
c) . 2.5kV
d) . 1.5kV

Q) . With reference to the nature of the supply. Which oneof the following can be determined by . calculation . enquiry ormeasurement ?
a) . Maximum-demandof the installation
b) . The rating ofthe circuit-protective-device
c) . The prospective-short-circuit-current . at the origin ofthe installation
d) . The C.S.A. ofthe tails

Q) . Which one of the following is . not part of the requirements for fault-protection
a) . Protective-earthing
b) . Protective-equipotential-bonding
c) . Automatic-disconnection
d) . Protection byinsulation of live-parts

Q) . BS-7671:2011: indentifies that the . C.S.A. of a conductor shall be determined by ?
a) . The admissible-maximum-temperature
b) . Thenominal-voltage
c) . Voltage-tolerances
d) . Theearthing-system

Q) . A residual-current-device ( RCD ) works by ?
a) . Magnetic-device-operating in the . event of a fault between. line & earth
b) . Magnetic-device-operatingin the . event of a fault between . neutral & earth
c) . Thin-element-operatingin the . event of a fault between . neutral & earth
d) . Thin-element-operatingin the . event of a fault between . line & earth
O.S.G. FICD - 11.0. P.105

Q) . A RCBO offersprotection against ?
a) . Short-circuit-current
b) . Short-circuit . overload-current and . earth-fault-current
c) . Short-circuit and overload-current
d) . Basic-contact
O.S.G. 3.1. p.23

 

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Q) . A person who is described as neither , askilled-person . nor an instructed-person is ?
a) . Competent-person
b) . Ordinary-person
c) . not an Electrician
d) . able to carryout . electrical-work in domestic-installation(s)
Definitions

Q) . in a TT -system when an overcurrent-protective-device is used the following condition must be . met: ( Zs x Ia ≤ Uo. Ia represents )
a) . The current causing-operation of the device within the time-stated in Table - 41.1
b) . The prospective-fault-current
c) . The nominal-rating ( In ) of the device
d) . 30mA

 

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BS-7671:2011: 2394 : Regulation(s) recongnises that installations . can only beverified . so far as is reasonably-practicable. “ In there own words “ Inspection & Testing .BS-7671:2011: differentiatesbetween .2394: Initial - verification . - New-work .- Additions & alterations . Chapter - 61 : Initial - Verification . p.189i) Inspection & Testing . Every-installation shall. During erection and on completion before being putinto service. Be Inspected & Tested to verify . sofar as is reasonably-practicable.Etc . 2395: Periodic inspection &Testing : Existing - installation . reasonably-practicable. Approach ( Careful-scrutiny ) backed up by testing .

 

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BS-7671:2011: 2394: Regulation(s) recongnises thatinstallations . can only be verified . so faras is reasonably-practicable. “ In there ownwords “

Inspection & Testing .
BS-7671:2011: differentiates between .
2394: Initial -verification .
- New-work .
- Additions & alterations .

Chapter - 61 : Initial - Verification . p.189
i) Inspection &Testing .
Every-installation shall. During erection and on completion before being putinto service. Be Inspected & Tested to verify . sofar as is reasonably-practicable.Etc .

2395: Periodic inspection & Testing :
Existing - installation . reasonably-practicable. Approach
( Careful-scrutiny ) backed up by testing .

 

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Test-methods :

GN-3 : Inspection& Testing .
612.2.1. - Continuity of protective-conductor(s) including . main and supplementary-equipotential-bonding.
612.2.2. - Continuity of ring-final-circuit-conductor(s)
542.4.2. - Tofacilitate measurement of the résistance of the . earthing-arrangements . meansshall be provided in an accessible-position .for disconnecting the ( Earthing-conductor) Such means may conveniently becombined with the . main-earhing-terminal . or bar . Any joint shall be capable of disconnection only by means of a tool

Earth-electrode-résistance . 612.7. . Where required.
Where the . earthing-system incorporates anearth-electrode as part of the installation . the electrode-résistance . toEarth shall be measured .
( Note ) Wherea measurement of ( R[SUP]A[/SUP] ) is not-practicable . themeasured-value of . external-earth-fault-loop-impedance may be Used .

Means of disconnection of Earthing-arrangements .

612.2.1. - Continuity of protective-conductor(s)
A continuity-test . shall be made . it is recommended thatthe test be carried-out with a supplyhaving a . no-load-voltage . between 4V . and 24V . d.c.or a.c. & a short-circuit-current ofnot less than . 200mA .

Re-cap . p.190
Testing : The testsof . Regulation(s) 612.2 to 612.6. where relevant . shall be carried-out in that order . before the installation is . Energized .
Where : theinstallation-incorporates an . Earth-Electrode . the test of . Regulation -612.7. shall also be carried-out . before theinstallation is . Energized .

If any test-indicates a failure to comply . that test & any preceding-test . theresults of which may have been-influenced . by the fault-indicated . shall be repeated after the fault has been rectified .

 

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My-point. 2394: it’s out their if we look for it.

BS-7671:2028:2011: has to state the facts .
GN-3. talks us through it . “ Answers“

Q) State :
Prerequisite-checksthat need to be applied . prior to undertaking an . Insulation-résistance-test.

i) Verify-supply is . isolated .

Dead-Test :

ii) All current-using-equipment . is disconnected.
iii) Disconnect any voltage-sensitive-equipment .
- pilotor indicator-lamps .
-voltage-sensitive-electronic-equipment . such as .
Dimmer-switches.
Touch-switches.
Delay-timers.
Electronic-starters- for fluorescent-lamps .
Emergency-lighting.
RCDs. and similar-equipment are disconnected . so that they are . Not subjected to test-voltages

 

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Bruce. still at collage .

2394: Installations should be inspected andtested . Before being put into service. “ Initial-verification “ 610.1.
2395: Atregular-intervals . therefore . “ Periodic-inspection “

Themain-reason for undertaking an . inspection and testing is to ensure that theinstallation is safe to Use .

Circuit-breaker: BS-EN-60898 . operation
• Thermal - overload .
• Magnetic - short-circuit-conditions .

Circuit-breakersrequire relatively . high-currents in order to operate . ( 3 x 32A = 96A . If ) or ( 5 x 32A = 160A . If ) B -type .
RCDs. operate in the region of - milli-amps . mA . ( 30mA ÷ 1000 = 0.03A ) RCD Earth-fault. 0.04mS

Q). What are the two-types of . Prospective-fault-current measured at the source . (Ipf ) . which needs to be recorded .
612.11. ( PFC )
i). Prospective-short-circuit-current .
ii). Prospective-earth-fault-current .
- at the origin .
- and at other-relevant-points in the installation.

Thelargest of the . two needs to be recorded .

GN-3. reminds us . p.54
The-Term. Prospective-fault-current . includes the . Prospective-short-circuit-current. & Prospective-earth-fault-current .it is the Greater of these .two-prospective-faults-currents . which should be determined . ( PSCC ) - ( PEFC )

 

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Q) the reason for undertaking a .continuity-test on the Line-conductor & circuit-protective-conductors . ofa ring-final-circuit.
Toensure that ring-final-circuit iscomplete . without interconnections .
Q) Two-other tests automatically carried outwhen undertaking the above. ↑↑ .
Polarity. ( R[SUP]1[/SUP] + R[SUP]2[/SUP] )