The reverse side of a three-pin plug with incorrect connection of wires is shown in the diagram below.
(a) Identify the fault in the above connection.
(b) Mention a risk factor involved, if the user operates the appliance with correcting it.
(c) Will the appliance function in the present situation? (Yes or No)
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Always remember the wiring code: Live on the right (fused pin), Neutral on the left, and Earth at the top. Incorrect wiring is a serious safety hazard.
(a) Identify the fault:
The standard wiring convention for a three-pin plug is:
- Live wire (Red or Brown) to the right pin (marked L).
- Neutral wire (Blue or Black) to the left pin (marked N).
- Earth wire (Green or Yellow/Green) to the top pin (marked E).
In the given diagram, the blue wire (Neutral) is connected to the live pin and the red wire (Live) is connected to the neutral pin. The fault is that the Live and Neutral wires have been swapped. (b) Mention a risk factor:
The switch of an appliance is always placed in the live wire to disconnect the high potential from the appliance's circuit when it is turned off. With the wires swapped, the neutral wire is now switched, while the live wire is permanently connected to the appliance's circuitry. This means that even when the appliance switch is in the 'off' position, the internal components are still at a high potential (live). If a user touches any part of the internal circuit (e.g., during cleaning or minor repair), they could complete the circuit to the earth and receive a severe or fatal electric shock. (c) Will the appliance function? Yes. An AC appliance requires a potential difference across its terminals to function. Since there is still a potential difference between the live and neutral pins of the socket, the appliance will function. However, it will be extremely unsafe.
