City & Guilds Electrical Installation (Level 3) Inspection, Testing and Commissioning Syllabus

Inspection, Testing and Commissioning syllabus — full chapter and topic list

Expand any chapter to see its topics and sub-topics. This is the whole examinable outline for Inspection, Testing and Commissioning in City & Guilds Electrical Installation (Level 3), not a summary of it.

1. 1

   Principles and Requirements of Inspection and Testing

   4 topics

   • Purpose and statutory basis
     • Initial verification versus periodic inspection
     • Requirements of BS 7671 Part 6
   • Documentation and information
     • Design data and previous certification
     • Risk assessment for live testing
   • Safe isolation before testing
   • Sequence of tests and rationale
2. 2

   Initial Verification: Inspection

   3 topics

   • Visual inspection schedule
     • Checking connections and identification
     • Presence of barriers, enclosures and notices
   • Verification of selection and erection
     • Suitability for external influences
     • Correct protective devices and ratings
   • Identifying defects and non-compliances
3. 3

   Dead Tests

   4 topics

   • Continuity testing
     • Continuity of protective conductors (R1+R2)
     • Continuity of ring final circuit conductors
   • Insulation resistance testing
     • Test voltages and minimum values
     • Disconnecting sensitive equipment
   • Polarity verification
   • Earth electrode resistance (dead method)
4. 4

   Live Tests

   4 topics

   • Earth fault loop impedance testing
     • External (Ze) and total (Zs) measurement
     • Comparing with maximum permitted values
   • Prospective fault current measurement
     • PSCC and PEFC determination
   • RCD operation testing
     • Trip times at rated and multiplied currents
     • Test button verification
   • Functional testing and phase rotation
5. 5

   Certification, Documentation and Fault Diagnosis

   4 topics

   • Certificates and reports
     • Electrical Installation Certificate
     • Minor Electrical Installation Works Certificate
     • Electrical Installation Condition Report (EICR)
   • Recording and interpreting results
     • Schedules of inspection and test results
     • Coding observations (C1, C2, C3, FI)
   • Fault diagnosis and rectification
     • Logical fault-finding procedures
     • Common faults: high resistance, short circuit, earth fault
   • Commissioning and handover

Inspection, Testing and Commissioning flashcards for City & Guilds Electrical Installation (Level 3)

18 of 51 cards from the Inspection, Testing and Commissioning deck — real questions with worked answers.

1. What is the statutory basis that makes inspection and testing of electrical installations a legal requirement in the UK workplace?

   The Electricity at Work Regulations 1989 (made under the Health and Safety at Work etc. Act 1974) require that electrical systems be constructed and maintained to prevent danger. BS 7671 (the IET Wiring Regulations) is the non-statutory code of practice used to demonstrate compliance.

2. What is the difference between initial verification and periodic inspection?

   Initial verification is carried out on a new installation (or addition/alteration) before it is put into service, resulting in an Electrical Installation Certificate (EIC). Periodic inspection assesses an existing installation in service to confirm it is still safe, resulting in an Electrical Installation Condition Report (EICR).

3. What are the three key requirements of inspection and testing as stated in BS 7671 Part 6?

   To verify, so far as is reasonably practicable, that the installation: (1) complies with the design, (2) is not damaged or defective so as to impair safety, and (3) meets the requirements of BS 7671. Inspection and testing must not cause danger to persons, livestock or property.

4. What documentation must be made available to the inspector before initial verification begins?

   The design data and assessment of general characteristics, including: maximum demand, earthing and bonding arrangements, type of supply (TN-S, TN-C-S, TT), prospective fault current, external earth fault loop impedance (Ze), circuit details, protective device ratings, and any departures from BS 7671.

5. Why must the prospective fault current and Ze be known or measured before energising for testing?

   They confirm that protective devices have adequate breaking capacity and that disconnection times can be achieved. Without them you cannot verify that the installation can safely interrupt a fault, which could lead to device failure or non-compliant earth fault protection.

6. State the steps of the safe isolation procedure before dead testing.

   (1) Identify the circuit/supply; (2) obtain permission to isolate; (3) select an approved voltage indicator and prove it on a known live source or proving unit; (4) isolate the supply; (5) lock off and apply a warning/caution notice (and keep the unique key); (6) verify dead at all points using the proving-unit-tested indicator; (7) re-prove the indicator on the known source.

7. What standard must a voltage indicator and proving unit comply with, and why is proving 'live-dead-live' essential?

   They should comply with GS38 (HSE guidance). Proving live before and after confirms the indicator was working when it showed 'dead', so a faulty meter cannot give a false safe reading.

8. List the correct sequence of dead (de-energised) tests for initial verification.

   (1) Continuity of protective conductors and main/supplementary bonding; (2) continuity of ring final circuit conductors; (3) insulation resistance; (4) polarity (verified by continuity); (5) earth electrode resistance (where applicable, dead method). These are done before energising.

9. List the correct sequence of live (energised) tests for initial verification.

   (1) Polarity confirmation; (2) earth fault loop impedance (Ze and Zs); (3) prospective fault current (if not determined by enquiry); (4) RCD operation; (5) functional testing (switchgear, controls, interlocks) and phase sequence. These follow the dead tests once the dead results are satisfactory.

10. Why must insulation resistance testing be carried out before energising the installation?

    It is a dead test that applies a high DC voltage; if the installation were live it would be dangerous and the meter could be damaged. It also confirms there are no short circuits or insulation faults before applying mains voltage, preventing danger when energising.

11. Why is polarity checked twice — once dead and once live — in the test sequence?

    The dead polarity test (by continuity) confirms correct connection before energising so no equipment is wrongly energised; the live polarity confirmation verifies the supply itself (and origin) is correctly connected before further live testing proceeds.

12. Name five items checked during the visual inspection schedule of an installation.

    Any five of: connection of conductors, identification of conductors, routing/protection of cables against mechanical damage, selection of conductors for current-carrying capacity and voltage drop, presence of fire barriers/seals, correct connection of accessories, presence of protective devices of correct rating, presence of warning/danger notices, presence of diagrams/labels, IP ratings, methods of protection against electric shock.

13. At what stage of the works should visual inspection ideally be carried out, and why?

    Inspection should precede testing and, where practicable, be carried out during erection as well as on completion. Carrying it out during erection allows access to parts (e.g. concealed cables, enclosures) that become inaccessible once the installation is complete.

14. What is 'verification of selection and erection' confirming?

    That equipment and wiring have been correctly chosen and installed in accordance with the design and BS 7671 — e.g. correct cable type and CSA for the load and installation method, correct protective device type/rating, adequate IP rating for the environment, and compliance with external influences.

15. Define a Code C1, C2, C3 and FI classification used on an EICR.

    C1 = Danger present, risk of injury, immediate action required; C2 = Potentially dangerous, urgent remedial action required; C3 = Improvement recommended (not a fail on its own); FI = Further investigation required without delay. C1 and C2 (and FI) result in an 'unsatisfactory' overall assessment.

16. What test method is used to verify continuity of a protective conductor, and what is its purpose?

    A low-resistance ohmmeter (typically applying ≥200 mA at 4–24 V DC) measures the conductor resistance. It confirms protective and bonding conductors are continuous, correctly connected, and of low enough resistance to carry fault current and operate protective devices.

17. Describe the R1 + R2 method for continuity of protective conductors.

    At the consumer unit, the line conductor (R1) and circuit protective conductor (R2) are temporarily linked together at the far end of the circuit (or the link is at the board). Measuring between line and cpc at each point gives R1 + R2; the highest value (furthest point) is recorded and used to calculate Zs.

18. For a ring final circuit, how is continuity (and correct interconnection) of the ring verified?

    Step 1: measure end-to-end resistance of line (r1), neutral (rn) and cpc (r2) loops separately. Step 2: cross-connect line of one leg to neutral of the other and measure between L and N at each socket (should be ~uniform). Step 3: repeat cross-connecting line to cpc; the reading at each socket equals $\frac{r_1 + r_2}{4}$ and should be substantially constant, confirming no interconnections or breaks.

See more Inspection, Testing and Commissioning flashcards →

Planning Inspection, Testing and Commissioning for City & Guilds Electrical Installation (Level 3)

Inspection, Testing and Commissioning (City & Guilds Electrical Installation (Level 3)) FAQ