This memory aid covers Memory Aid within Mains Electricity & Safety for GCSE Physics. Revise Mains Electricity & Safety in Electricity for GCSE Physics with 18 exam-style questions and 30 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 12 of 16 in this topic. Use it for quick recall, then test yourself straight afterwards so the memory aid becomes usable in an answer.
🧠 Memory Aid
Wire colours — "Brown Lives, Blue Neutral, Green-Yellow Earth":
Brown = Live (Be careful — it's Lethal!)
Blue = Neutral (think: bland/safe at 0 V)
Green/Yellow = Earth (think: grass and sun = the earth and ground)
Fuse selection rule — "Just Above, Never Below":
Calculate the normal current using I = P/V. Choose the fuse that is just above this value from the available options (3 A, 5 A, 13 A). Never choose one that's below — it would blow immediately. Never choose one that's much higher — it won't protect.
Earth wire purpose — "Earth Escapes, Fuse Finishes":
The Earth wire provides an escape route for fault current. The large current then causes the Fuse to Finish (melt), cutting the circuit.
Practice questions for Mains Electricity & Safety
What does AC stand for, and how does it differ from DC?
Explain how a fuse protects an electrical circuit from damage.