Accessories and Installation
What the exam tests
This domain tests switches, sockets, plug tops, ceiling roses, holders, fan regulators, distribution boards and correct mounting and connection of domestic accessories.
Core rules
- A switch must be connected in the phase conductor, not the neutral, so the appliance is dead when switched off.
- Three-pin sockets require a protective earth connected to the plug top earth pin and to the appliance metal body. The earth pin is longer and makes first, breaks last.
- Match accessory rating to load: 6 A for lighting, 16 A for power circuits such as geysers and air conditioners. Do not feed a 16 A socket from a 6 A lighting circuit.
- Terminals must be tight; loose connections cause heat. Use correct cable size and leave no exposed conductor.
- Bathroom and outdoor accessories need suitable ingress protection and RCD protection.
Worked example
Wire a 16 A socket for a 2 kW geyser. The current is 2000/230 = 8.7 A. Connect phase to L, neutral to N and earth to E. Feed the socket from a 16 A circuit protected by a 30 mA RCCB. The switch is in the phase. After wiring, test polarity, earth continuity and insulation before energising.
Traps
Do not switch the neutral. Do not omit the earth because the appliance works. Do not use a 6 A plug top on a 16 A socket or a 16 A appliance. Do not leave stranded strands outside the terminal. Do not mount accessories where water spray reaches them.