C & G 2391-50, Initial Verification and Certification;  revision paper 1

1. Which of the following best describes the status of an inspector who is carrying out inspection  and testing?

   a).   Ordinary person

   b).   Duty person

   c).   Competent person

   d).   Responsible person 


2.  Which is the most suitable location to test for full isolation and safety of a lighting circuit, to ensure it is safe to work on?

   a).   On the supply side of the circuit protective device

   b).   At the supply intake position

   c).   At the last luminaire on the circuit

   d).   On the load side of the circuit protective device


3.  Which of the following needs to be isolated from a circuit while the circuit is tested for insulation resistance?

   a).   Current using devices

   b).   Circuit connections

   c).   Contact switches

   d).   Circuit conductors


4. When completing the initial verification of an installation, the interval to the next inspection must be recorded where?

   a).   minor works certificate

   b).   periodic inspection report detailing observations

   c).   schedule of test results

   d).   electrical installation certificate


5  A commercial building is to be isolated in order for certain tests to be carried out. Which of the following hazards would exist if client’s permission was not obtained before isolating the supply?

    a)         Persons using the building are at risk of electric shock

    b)         Self-contained emergency lighting units would not operate

    c)         Person using services such as lifts may be trapped

    d)         Data systems would be affected by electro-magnetic interference

6.  The non-statutory document that is applicable to the construction and use of test equipment and test leads is which of these?

   a).      The on-site guide

   b).      The Electricity at Work Regulations 1989

   c).      Guidance Note GS 38

   d).      The Provision and Use of Work Equipment Regulations


7.  Which one of the following tests is carried out to confirm requirements of BS7671 for automatic disconnection of supply have been met?

   a).      Earth fault loop impedance

   b).      RCD testing

   c).      Prospective fault current testing

   d).      Insulation Resistance

8.  A test for additional protection is to be carried out on an RCD, having a maximum tripping current as stated in BS7671. Which one of the      following shows the correct instrument settings in order to perform the tests?


   a).      I∆n = 100mA ,  test current = I∆n x 1  

   b).      I∆n = 30mA ,  test current = I∆n x 5  

   c).      I∆n = 30mA ,  test current = I∆n x 1

   d).     I∆n = 150mA ,  test current = I∆n x 5  

9.  A test meter displays a test reading value in ‘MΩ’ . The test being done is which of the below?


   a).      Insulation resistance

   b).      Earth loop impedance

   c).      RCD testing

   d).      Continuity testing

10.  A new ring-final circuit is being tested. The first four tests, in the right order are?

   a).      Ring final circuit continuity, insulation resistance, earth loop impedance, RCD test

   b).     Continuity of cpc, insulation resistance, polarity, earth loop impedance

   c).     Ring final circuit continuity, polarity, RCD, earth loop impedance

   d).     Ring final circuit continuity, insulation resistance, polarity, earth loop impedance

11.  Which one of the following is not a requirement when using test instruments for initial verification?


   a).     Recording the name of the instrument supplier

   b).     Ensuring calibration or regular test records are current

   c).     Checking tester and leads for physical damage

   d).     Ensuring the instrument is set up and used correctly



12. Which one of the following is the main purpose for verifying suitable connection of main bonding conductors?

   a).     To ensure they reduce the values of earth fault loop impedance

   b).     To confirm they provide an equal potential at the point of connection, between extraneous and exposed conductive parts

   c).     To confirm they provide a suitable path for earth fault currents

   d).     To ensure they provide a suitable path for earth leakage currents



13. A continuity of cpc test performed using the long lead method, at the furthest point on a radial circuit would provide a value of?

   a).     R1 + R2

   b).     R1

   c).     R2

   d).     r2


14. If the length of a cable was halved the insulation resistance value would be what?

   a).     halved

   b).     the same

   c).     doubled

   d).     quartered



15. When carrying out a test of earth fault loop impedance at the origin, the installation is isolated because ?

   a).     connected equipment could be damaged

   b).     The main earth conductor must be removed from the MET for testing

   c).     Accessible metalwork would otherwise become live to 500V during the test

   d).     There is a risk of damage to the tester

16.  When testing a ring final circuit wired with PVC/PVC twin/cpc cable for continuity, the r1 value is 0.3 Ω . The expected value for R1+R2  would be which of the following?

   a).     0.6 Ω

   b).     0.15 Ω

   c).     0.8 Ω

   d).     0.2 Ω  



17.  The normal method of compensating for the difference between ‘testing temperature’ and ‘normal operating temperatures’ when applying  earth fault loop impedance values is which of the following?

   a).      Apply a correction factor of 1.67 to tabulated values ( x 1.67)

   b).      Apply a correction factor of 0.8 to tabulated values  ( x 0.8)

   c).      Apply a correction factor of 0.8 to measured values ( x 0.8)

   d).     Apply a correction factor of 0.725 to measured values ( x 0.725)



18.  The breaking capacity of a protective device must comply with which of the following?

   a).      Exceed the PFC

   b).     Not exceed PFC

   c).     Cause the operation of the device within 5 seconds

   d).     Not exceed the tripping current of any associated RCD



19. A 100mA RCD is utilized to provide fault protection. The maximum applied test current used when testing is which of the following?


   a).     30mA

   b).    100mA

   c).    150mA

   d).    500mA



20.  When testing insulation resistance between conductors on a three-phase 110V circuit, the test voltage used should be?


   a).      1000V d.c.

   b).      500 V d.c..

   c).      500 V a.c.

   d).      250 V a.c..



Answer paper 1 – Refer to Guidance note 3 unless otherwise stated

    1)   C.      - 1.2,         Required competence

    2)   D.      -                Covered in course notes

    3)   A.      -  2.7.7      Insulation resistance

    4)   D.      -  5            Form 1 and Form 2

    5)   C.      -                Covered in course notes

    6)   C.      - 1.1,         Safety (3)

    7)   A.      -  2.7.14    Protection by a.d.s

    8)   B.      -  2.7.18    Additional protection

    9)   A.      -                Covered in course notes

  10)   D.      -  2.7.4      Sequence of tests

  11)   A.      -  1.1         Safety

  12)   B.      -                Covered in course notes

  13)   C.      -  2.7.5      Test method 2

  14)   C.      -                Covered in course notes

  15)   B.      -  2.7.15    Measurement of Ze

  16)   D.      -  2.7.6      step 1 and step 3

  17)   B.      -  2.7.15    App.2 – verification of Zs results (4)

  18)   A.      -  2.7.16    Refer to Regulation 434.5.1

  19)   B.      -  2.7.18    (Table 2.9) also Refer to Regulation 411.4.5

  20)   B.      -  2.7.7      Table 2.2