C&G 2391 Inspection and Testing Day Questions for Roger

Roger and I took the course together and I said I would ask him some questions that I will make up. So you might wish to check your knowledge ready for the exam.

1. There are three reports that an inspector can issue, what are these? Secondly give an example where each would be used.
2. What is the period between inspections for electrical installations in commercial premises? What reasons could an inspector reduce the period of time between inspections for a domestic premise?
3. What is the none statutory publication relating to test instruments? What size fuse and type is recommended to be fitted in an instrument's test leads.
4. Which earthing arrangement would have a maximum of 21 ohms if obtained by enquiry or the maximum allowed under BS 7671?
5. Give the order in which the first 5 dead tests would be carried out?
6. List the six tests that could be carried out on an 30mA RCD and what results would be expected for each test?
7. Explain what is meant by the terms Zdb, Ze, Zs, (R1+R2)? Show the formula for calculation of the earth fault impedance.
8. EEBADS is an abbreviation for what? What disconnection time is required for sockets when protected by a BS 88 fuse and also the time for other applications.
9. Give four examples of services in a building that would require bonding? What is the wording on the label required where an earth connection connects to services.
10. What is the difference between SELV and PELV? What voltage would an insulation resistance tester be set to test either SELV or PELV? What is the minimum resistance allowed?
11. When carrying out an insulation resistance test on a 6 Way consumer unit the following tests where recorded 5, 3, 20, 10, 20, 50 meg ohms. What is the overall resistance for the system and is this acceptable. Give three possible reasons for the lower tests.
12. What precautions would need to be taken prior to carrying out an insulation test.
13. The csa of the conductors in a cable are doubled, what effect would this have on the resistance. If copper is heated will the resistance increase or decrease?
14. A prospective phase/neutral fault current of 2.3kA is obtained along with a phase/earth prospective fault current of 3.4kA, which value would need to be recorded and why?
15. Ring final circuits can be tested using three stages. Briefly explain the stages? When testing at the sockets the resistance begins to increase after the third socket, what could be a possible reason?
16. Give three examples of where the polarity needs to be checked.

Not a full 20 but still enough to have a go at testing your knowledge.