🔍 Initial Verification, Inspection and Testing (Part 6)

1. Which regulation in BS 7671:2018+A2:2022 requires that every installation be inspected and tested during erection and on completion before being put into service?

1. Regulation 641.1
2. Regulation 132.1
3. Regulation 543.1
4. Regulation 411.3

Regulation 641.1 requires initial verification (inspection, testing and certification) during erection and on completion before an installation is put into service. (BS 7671:2018+A2:2022, Regulation 641.1 (Chapter 64))

2. Initial verification under Regulation 641.1 is carried out to confirm, so far as is reasonably practicable, that what has been satisfied?

1. The requirements of BS 7671 have been met
2. The wishes of the customer have been met
3. The lowest possible cost has been achieved
4. The manufacturer's marketing claims are true

Initial verification confirms, so far as is reasonably practicable, that the requirements of BS 7671 have been met. (BS 7671:2018+A2:2022, Regulation 641.1)

3. According to Regulation 641.1, initial verification comprises which three activities carried out in sequence?

1. Inspection, testing and certification
2. Design, installation and maintenance
3. Planning, costing and invoicing
4. Bonding, earthing and labelling

Initial verification comprises inspection, testing and certification carried out in that sequence. (BS 7671:2018+A2:2022, Regulation 641.1)

4. When should inspection and testing of a new installation be carried out to comply with Regulation 641?

1. During erection and on completion, before being put into service
2. Only once the installation has been energised and in use for a week
3. Only when a fault is later reported by the user
4. At the next periodic inspection, several years after completion

Regulation 641.1 requires verification both during erection and on completion, before the installation is put into service. (BS 7671:2018+A2:2022, Regulation 641.1)

5. During initial verification, in what order should inspection and testing normally be undertaken?

1. Inspection first, then testing
2. Testing first, then inspection
3. Both simultaneously while energised
4. Certification first, then inspection

Inspection precedes testing, and inspection is normally carried out with the installation disconnected from the supply. (BS 7671:2018+A2:2022, Regulations 642 and 643; IET Guidance Note 3)

6. How should the inspection stage of initial verification normally be carried out with respect to the supply?

1. With the installation disconnected from the supply (dead)
2. With the installation fully energised and loaded
3. With only the lighting circuits energised
4. With the supply connected but the main switch closed

Inspection is normally carried out first, with the installation disconnected from the supply (dead). (BS 7671:2018+A2:2022, Regulation 642; IET Guidance Note 3)

7. Which document must be issued on completion of the initial verification of a new installation?

1. An Electrical Installation Certificate with schedules of inspections and test results
2. A Minor Electrical Installation Works Certificate only
3. A verbal confirmation to the client
4. A periodic inspection report (EICR)

On completion of a new installation an Electrical Installation Certificate, together with schedules of inspections and test results, must be issued. (BS 7671:2018+A2:2022, Section 644 (Regulation 644.4))

8. For minor works that do not include the provision of a new circuit, which certificate is appropriate following verification?

1. A Minor Electrical Installation Works Certificate
2. An Electrical Installation Certificate
3. An Electrical Installation Condition Report
4. No certificate is required for minor works

A Minor Electrical Installation Works Certificate is used for minor works that do not include a new circuit; an EIC is used for new installations or new circuits. (BS 7671:2018+A2:2022, Section 644 (Regulation 644.4))

9. Which regulation requires that the prescribed tests be carried out, where relevant, in the sequence given before the installation is energised?

1. Regulation 643.1
2. Regulation 641.1
3. Regulation 132.16
4. Regulation 514.9

Regulation 643.1 requires the prescribed tests (643.2 to 643.11) to be carried out in sequence, where relevant and appropriate. (BS 7671:2018+A2:2022, Regulation 643.1)

10. Which of the following correctly describes the general grouping of tests during initial verification?

1. Dead tests are completed before the installation is energised for live tests
2. Live tests are always completed before any dead tests
3. All tests are carried out with the supply connected
4. Dead and live tests may be performed in any order

Dead tests (such as continuity, insulation resistance and polarity) must be completed before the installation is energised for live tests. (BS 7671:2018+A2:2022, Chapter 64; IET Guidance Note 3)

11. Which test is the first electrical test in the prescribed sequence of Regulation 643?

1. Continuity of protective conductors
2. Earth fault loop impedance
3. RCD operation
4. Prospective fault current

Continuity of protective conductors (Regulation 643.2) is the first electrical test in the sequence and is a dead test. (BS 7671:2018+A2:2022, Regulation 643.2)

12. Why is continuity of protective conductors verified before the insulation resistance test in the prescribed sequence?

1. So the insulation test voltage is applied over the full length of the conductors to be tested
2. Because insulation resistance can only be measured on a dead installation after energising
3. Because continuity testing requires the supply to be connected first
4. Because the two tests use the same applied voltage and order is irrelevant

Verifying continuity first ensures the conductors are sound so the insulation resistance test voltage is applied over their full length. (IET FAQ, Inspection and Testing (electrical.theiet.org))

13. For a 230 V final circuit (not SELV or PELV), what is the insulation resistance test voltage and minimum acceptable value?

1. 500 V DC and 1.0 megohm
2. 250 V DC and 0.5 megohm
3. 1000 V DC and 1.0 megohm
4. 500 V AC and 2.0 megohm

For circuits up to and including 500 V (excluding SELV/PELV), the test voltage is 500 V DC with a minimum insulation resistance of 1.0 megohm. (BS 7671:2018+A2:2022, Table 64 (Table 64.1))

14. For SELV and PELV circuits, what insulation resistance test voltage and minimum value apply?

1. 250 V DC and 0.5 megohm
2. 500 V DC and 1.0 megohm
3. 1000 V DC and 1.0 megohm
4. 250 V DC and 1.0 megohm

For SELV and PELV circuits the test voltage is 250 V DC and the minimum insulation resistance is 0.5 megohm. (BS 7671:2018+A2:2022, Table 64 (Table 64.1))

15. An installer is calculating Zs for a final circuit during verification. Which method does Regulation 643.7.3 permit?

1. Adding the measured R1+R2 of the circuit to the external loop impedance Ze
2. Subtracting Ze from the measured insulation resistance
3. Multiplying the continuity reading by the RCD operating time
4. Using the prospective fault current divided by the supply voltage

Zs may be determined by adding the measured R1+R2 of the circuit to the external earth fault loop impedance Ze. (BS 7671:2018+A2:2022, Regulation 643.7 / 643.7.3.1)

16. Which of the following design details must be made available before initial verification commences, per Regulation 644.1.1?

1. External earth fault loop impedance (Ze), maximum demand and type of earthing arrangement
2. The name and address of every future occupier of the building
3. The expected resale value of the property
4. The brand of test instrument the inspector intends to use

Regulation 644.1.1 requires design information such as Ze, maximum demand, earthing arrangement, nominal voltage, prospective fault current and the protective device details. (BS 7671:2018+A2:2022, Regulation 644 / 644.1.1)

17. Which regulation governs the verification of polarity during initial verification?

1. Regulation 643.6
2. Regulation 643.2
3. Regulation 643.8
4. Regulation 641.1

Regulation 643.6 covers the verification of polarity during initial verification. (BS 7671:2018+A2:2022, Regulation 643.6)

18. A polarity check during initial verification must confirm that fuses and single-pole switching devices are connected where?

1. In the line conductor only
2. In the neutral conductor only
3. In the protective conductor only
4. In both the line and neutral conductors

Polarity verification confirms that fuses, single-pole switches and protective devices are connected in the line conductor only. (BS 7671:2018+A2:2022, Regulation 643.6)

19. At which stages of testing is polarity verified?

1. As a dead test and confirmed on energisation
2. Only as a live test after energisation
3. Only by visual inspection before any testing
4. Only during periodic inspection, not initial verification

Polarity is checked as a dead test in the sequence and then confirmed again on energisation (live). (BS 7671:2018+A2:2022, Regulation 643.6)

20. In the prescribed dead-test sequence of Regulation 643, where does polarity testing fall relative to insulation resistance and live testing?

1. After insulation resistance and before the installation is energised for live tests
2. Before continuity of protective conductors and before insulation resistance
3. After earth fault loop impedance and after RCD testing
4. It is only ever carried out as the very last live test

Polarity is one of the dead tests, carried out after insulation resistance and completed before the installation is energised for live testing. (BS 7671:2018+A2:2022, Chapter 64; IET Guidance Note 3)

21. Which instrument and method is most appropriate for the dead polarity test of a final circuit during initial verification?

1. A low-resistance ohmmeter (continuity tester) on the de-energised circuit
2. An earth fault loop impedance tester on the live circuit
3. An RCD tester applying 30 mA to the circuit
4. An insulation resistance tester at 500 V DC between line and neutral

Dead polarity verification is performed with a low-resistance ohmmeter (continuity tester) on the de-energised circuit, typically combined with the continuity test. (BS 7671:2018+A2:2022, Regulation 643.6; IET Guidance Note 3)

22. During a dead polarity check at an Edison screw lampholder, what is the inspector confirming?

1. That the line conductor connects to the centre contact and not the outer screw shell
2. That the neutral connects to the centre contact and the line to the shell
3. That the protective conductor is connected to the centre contact
4. That both line and neutral are linked at the shell

Correct polarity at an ES lampholder requires the line conductor to connect to the centre contact, leaving the accessible outer screw shell connected to neutral. (BS 7671:2018+A2:2022, Regulation 643.6)

23. An installer omits the live confirmation of polarity after energising, having only completed the dead polarity test. Why is this non-compliant with Regulation 643.6?

1. Polarity must be both checked dead and confirmed correct on energisation
2. A dead polarity test alone is sufficient and live confirmation is never needed
3. Polarity is only a live test, so the dead check was the error
4. Polarity verification is optional once insulation resistance has passed

Regulation 643.6 requires polarity to be verified as a dead test and then confirmed correct on energisation, so omitting the live confirmation is non-compliant. (BS 7671:2018+A2:2022, Regulation 643.6)

24. Polarity verification at a socket-outlet during initial verification should confirm which of the following?

1. The line, neutral and earth conductors are connected to their correct terminals
2. Only that the earth terminal has continuity to the main earthing terminal
3. Only that the measured insulation resistance exceeds 1.0 megohm
4. Only that the RCD trips within 300 ms

Polarity at a socket-outlet confirms that line, neutral and earth are connected to their correct terminals so equipment is correctly connected. (BS 7671:2018+A2:2022, Regulation 643.6)

25. During initial verification, which set of tests must always be completed before the installation is energised?

1. The dead tests
2. The live tests
3. The earth fault loop impedance measurements
4. The RCD operation tests

Dead testing must be completed before the installation is energised, with live tests following on energisation. (BS 7671:2018+A2:2022, Chapter 64; IET Guidance Note 3)

26. Which sequence correctly lists the four principal dead tests in the order they should be carried out?

1. Continuity of protective conductors, ring final circuit continuity, insulation resistance, polarity
2. Insulation resistance, polarity, continuity of protective conductors, ring final circuit continuity
3. Polarity, insulation resistance, ring final circuit continuity, continuity of protective conductors
4. Ring final circuit continuity, insulation resistance, continuity of protective conductors, polarity

The dead test sequence is continuity of protective conductors, ring final circuit continuity, insulation resistance, then polarity. (BS 7671:2018+A2:2022, Chapter 64; IET Guidance Note 3)

27. Which is the first electrical test to be carried out in the initial verification test sequence?

1. Continuity of protective conductors
2. Insulation resistance
3. Earth fault loop impedance
4. Polarity

Continuity of protective conductors is the first electrical test in the sequence under Regulation 643.2. (BS 7671:2018+A2:2022, Regulation 643.2)

28. Why is continuity of protective conductors verified before the insulation resistance test?

1. So that the insulation resistance test voltage is applied over the full length of the conductors to be tested
2. Because insulation resistance damages protective conductors
3. Because continuity can only be measured at 500 V DC
4. Because polarity must be confirmed before any continuity test

Confirming continuity first ensures the insulation resistance test voltage is applied across the full length of the conductors under test. (IET FAQ, Inspection and Testing (electrical.theiet.org))

29. By what means must the continuity of protective conductors, including main and supplementary bonding conductors, be verified?

1. By measurement of resistance
2. By measurement of insulation resistance at 500 V DC
3. By visual inspection only
4. By measurement of earth fault loop impedance

Continuity of protective conductors is verified by measurement of resistance under Regulation 643.2. (BS 7671:2018+A2:2022, Regulation 643.2 / 643.2.1)

30. Between which points is insulation resistance measured during initial verification?

1. Between live conductors, and between live conductors and the protective conductor connected to the earthing arrangement
2. Between the line conductor and the supply neutral only
3. Between the protective conductor and the gas service pipe only
4. Between each socket-outlet and the nearest accessory

Insulation resistance is measured between live conductors and between live conductors and the protective conductor connected to earth. (BS 7671:2018+A2:2022, Regulation 643.3 / 643.3.1)

31. For a 230 V circuit (not SELV or PELV), what test voltage and minimum insulation resistance apply?

1. 500 V DC, minimum 1.0 megohm
2. 250 V DC, minimum 0.5 megohm
3. 1000 V DC, minimum 1.0 megohm
4. 500 V AC, minimum 0.5 megohm

For circuits up to and including 500 V (excluding SELV/PELV), the test is 500 V DC with a 1.0 MΩ minimum. (BS 7671:2018+A2:2022, Table 64.1)

32. What test voltage and minimum insulation resistance value apply to SELV and PELV circuits?

1. 250 V DC, minimum 0.5 megohm
2. 500 V DC, minimum 1.0 megohm
3. 250 V AC, minimum 1.0 megohm
4. 1000 V DC, minimum 0.5 megohm

SELV and PELV circuits are tested at 250 V DC with a minimum acceptable value of 0.5 MΩ. (BS 7671:2018+A2:2022, Table 64.1)

33. For a circuit with a nominal voltage above 500 V, what insulation resistance test voltage and minimum value are required?

1. 1000 V DC, minimum 1.0 megohm
2. 500 V DC, minimum 1.0 megohm
3. 1000 V DC, minimum 0.5 megohm
4. 250 V DC, minimum 1.0 megohm

Circuits above 500 V are tested at 1000 V DC with a minimum insulation resistance of 1.0 MΩ. (BS 7671:2018+A2:2022, Table 64.1)

34. An insulation resistance test on a 230 V final circuit returns a reading of 0.8 MΩ. Which conclusion is correct?

1. The reading is below the 1.0 MΩ minimum and the circuit requires further investigation
2. The reading is acceptable because it exceeds 0.5 MΩ
3. The reading is acceptable because the test voltage was 500 V DC
4. The circuit may be energised because polarity was confirmed

A 230 V circuit must achieve at least 1.0 MΩ, so 0.8 MΩ is unacceptable and needs investigation. (BS 7671:2018+A2:2022, Table 64.1)

35. What does the polarity test on a dead installation confirm regarding fuses and single-pole switches?

1. That they are connected in the line conductor only
2. That they are connected in the neutral conductor only
3. That they are connected in the protective conductor
4. That they are double-pole devices

Polarity verifies that fuses, single-pole switches and protective devices are connected in the line conductor only. (BS 7671:2018+A2:2022, Regulation 643.6)