Reference no: EM132588230

Assignment - Electrical Installation Questions

Question 1 - With reference to electric cables, state

a) Two functions of insulation.

b) Three types of insulation materials.

c) Outline Four rating factors that are considered when determining the current carrying capacity of electric cables.

d) Calculate the cross-sectional area of a cable when labelled as 7/0.642.

e) A 3- core copper cable supplies to a 240V single phase load of 25KW at 0.85 power factor lagging. The cable is 52 metres long and each conductor has a cross sectional area of 35mm². Determine the voltage drop in the cable. Take resistivity of copper is 17.5µ?mm.

Question 2 - a) Explain reasons for earthing electrical installations.

b) Outline four methods used to achieve the earthing of an installation.

c) List six types of earth electrodes.

Question 3 - a. Define the following terms au used in electrical circuit protection

i. Fusing factor

ii. Fusing current

b. State four advantages of circuit breakers over fuses.

c. Draw a labelled diagram of a high breaking capacity fuse.

d. With aid of a diagram explain the operation of a single phase current operated earth leakage circuit breaker.

Question 4 - a) State three reasons for protecting an installation.

b) With aid of a labelled circuit diagram, describe the 'earth fault loop path'.