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GCSE Physics · key term
The ground, treated as being at approximately 0 V, together with conductors electrically connected to it.
Used by Edexcel
Specification 10.41 · Paper 2
Revise: Dangers of MainsThe live wire is at a potential difference of about 230 V relative to earth, while earth is approximately 0 V. If a conducting path is provided between them, this large potential difference drives a current through the path.
For an ‘explain’ question, give the complete chain: a connection to earth creates a large potential difference across the path, current flows, and that current can cause a severe or fatal shock.
Distinguish the two cases clearly: a person forming the path risks electrocution, whereas a low-resistance earth wire carries a fault current so that a fuse or circuit breaker disconnects the supply.
Do not claim that an appliance’s earth wire normally carries current; it should carry current only when a fault makes a conductive part live.
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