ME5507/ME5627: Electrical Services Design

Subject ME5507/ME5627: Electrical Services Design


1. (a) How do we ensure that the live conductors of a cable are adequately protected against the effects of overload?
(b) What limitations do we need to impose on the volt drop in electrical distribution design?
(c) Why are we required to calculate the value of prospective short circuit current at points in the distribution system?
(d) Why do we impose an upper limit on the earth fault loop impedance, ZS, for each circuit?
(e) How do we ensure that the circuit protective conductor is adequately protected against the effects of fault current?

2. (a) Draw a single-line schematic diagram of the electrical distribution.

(b) For both of the circuits ref. 6 and 7 state your choice of the type (not the size) of the following:-

(c) Calculate the cable sizes for circuits 6 and 7, demonstrating how you have satisfied each of the five requirements from question 1.

3. To exploit locally available wind power, an on-site micro-generator rated at less than 16 A is to be installed.
(a) Illustrate on your single-line schematic how this might be connected to the distribution system.
(b) Explain how the generator connection can be designed to be compliant with the requirements from question 1.