C&G 2391 MOCK Exam One With Answers

This is part of an actual past exam paper. It consists of 20 brief questions, each carrying 3 marks. City and Guilds recommended that candidates allow approximately l hour for this section.

Answers at the end of the C&G 2391 mock exam.

1. What are the THREE areas of investigation that you should consider when carrying out a periodic inspection of an electrical installation? (3 marks)

2. When performing an insulation resistance test, what are the tabulated test voltages to be applied and the minimum acceptable value of insulation resistance for the following installation types: (3 marks)
- i) Low voltage circuits up to 500 volts
- ii) Low voltage circuits greater than 500 volts
- iii) SELV installations

3. When performing a continuity test on the CPC of a radial circuit supplying a single socket outlet, a temporary link and a milliohm meter is used: (3 marks)
State:
- i) Where the temporary link is placed?
- ii) Where the probes of the milliohm meter are connected?
- iii) What do the readings on the milliohm meter represent?

4. State the effect on: (3 marks)
- i) Conductor resistance when the conductor length increases?
- ii) Insulation resistance when the cable length increases?
- iii) Conductor resistance when the conductor c.s.a. increases?

5. State THREE examples of locations where additional requirements may apply to electrical installations? (3 marks)

6. List THREE precautions to be taken before commencing an insulation resistance test on an installation? (3 marks)

7. An enclosure has been constructed on site to house electrical equipment, which may be exposed to water.
State the IP codes to which the enclosure must comply as a minimum requirement? (3 marks)

8. State three main items for which you would require relevant information, in order to correctly carry out an initial verification on a new installation. (3 marks)

9. An electrical installation certificate should be accompanied by signed documentation regarding the three stages of an installation. What are these stages? (3 marks)·

10. List the test instruments used during a test on an electrical  installation, gave the following readings: (3 marks)
- i) >999 M Ohm
- ii) 10 kA
- iii) 18 ms