Though most of the candidates did not attempt this question, the few that attempted it could not sketch correctly the circuit diagram of an earth return system as asked in part (a)(i).

They could not also state the merits of an earth return system.  The correct circuit diagram of an earth return system is given below:

The merits of an earth return system include

• it is more compact;
• it uses fewer cables;
• it reduces fire risk;
• it is easy to trace faults;
• it is cheaper and lighter in weight.