Understand that most electrical appliances are connected to the mains supply using a three-core cable.
Identify the colour coding of the insulation covering each wire: brown for the live wire, blue for the neutral wire, and green and yellow stripes for the earth wire.
Explain the function of each wire: the live wire carries the alternating potential difference from the supply, the neutral wire completes the circuit, and the earth wire acts as a safety mechanism to prevent the appliance from becoming live.
Recall that the potential difference between the live wire and earth is approximately 230 V, while the neutral wire and the earth wire are at or close to earth potential (0 V).
Understand that the earth wire only carries a current in the event of a fault.
Explain why a live wire remains dangerous even when a switch in the mains circuit is open.
Assess the critical dangers of creating any connection between the live wire and earth.
