Accessories and Installation Practice
This domain tests switches, sockets, ceiling roses, lamp holders, fan regulators, bell pushes, MCBs, RCCBs and their correct installation. The exam focuses on polarity, earthing, load matching, enclosure protection and safe termination.
Core rules
- A one-way switch controls a lamp from one position; a two-way switch is used at each end of a staircase circuit.
- Socket outlets must be matched to the load. A 6 A socket is for small appliances; a 16 A socket is for heavy appliances such as geysers and air conditioners.
- The earth pin is longer and thicker so it makes connection first and breaks last. Metal appliance bodies must be earthed.
- Bathrooms, kitchens and outdoor locations need suitable IP-rated accessories and RCCB protection. Moisture increases shock risk.
- Terminations must be tight, with no stray strands, and enclosure covers must be replaced after work.
Worked example
A 2,000 W geyser on 230 V draws I = 2000/230 = 8.70 A. A 6 A socket is unsuitable because it is overloaded. Use a 16 A socket with 2.5 mm² copper cable, a 16 A MCB and 30 mA RCCB protection for the bathroom circuit. The earth conductor must be connected to the geyser body.
Traps
Do not use a 6 A socket for a geyser. Do not connect the switch in the neutral. Do not leave the earth terminal disconnected because the appliance works. Do not install ordinary accessories in wet locations.