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GCSE Physics · key term
The mains conductor that supplies an alternating potential difference to an appliance and can be at a dangerous potential difference from earth.
Used by AQA, Edexcel and OCR
Specification 4.2.3.2 · Paper 1
The brown conductor in a mains cable that is at an alternating potential difference of about 230 V relative to earth.
Revise: Mains electricityThe live wire has an alternating potential relative to earth. For the UK mains supply, its potential difference from earth is about 230 V.
Specification 10.37, 10.39, 10.40, 10.41 · Paper 2
The mains conductor that carries the alternating potential difference from the electricity supply; its insulation is brown.
Revise: Live and Neutral WiresThe live wire carries the alternating potential difference from the mains supply to the appliance. Its insulation is brown.
The mains conductor that has a large alternating potential difference from earth and supplies electrical energy to an appliance.
The mains wire whose potential alternates relative to the neutral and earth wires; its working potential difference from either is about 230 V.
The conductor in a mains cable that is at a large alternating potential difference relative to earth and supplies energy to an appliance.
Specification P8.2i, P8.2j · Paper 2 (Foundation), Paper 4 (Higher)
The mains wire that supplies an alternating potential difference to an appliance.
Revise: Mains wiresThe live wire supplies the alternating potential difference that drives current through the appliance. The neutral wire completes the normal circuit. Because the supply is alternating, the current changes direction; calling neutral the return wire describes its role in completing the circuit, not a permanent direction of flow.
Paper 1, Paper 2
The mains conductor that supplies the appliance and has a potential difference of about 230 V from the neutral and earth wires.
Revise: Mains Electricity and Electrical SafetyThe live wire, coloured brown, carries the alternating supply to the appliance. It is about 230 V relative to both neutral and earth.
An open switch stops current in the circuit it breaks, but it does not make every part of the live wire safe: the live conductor on the supply side can still be at about 230 V relative to earth.
When asked for the difference in function, describe both wires: the live wire carries the alternating potential difference from the supply, whereas the neutral wire completes the circuit.
Do not say that only the live wire carries current. During normal operation, current passes through both the live and neutral wires, and its direction continually alternates.
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