ElectricityDeep Dive
Safety Devices — How They Protect You
Part of Mains Electricity & Safety — GCSE Physics
This deep dive covers Safety Devices — How They Protect You within Mains Electricity & Safety for GCSE Physics. Revise Mains Electricity & Safety in Electricity for GCSE Physics with 13 exam-style questions and 30 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 5 of 17 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 5 of 17
Practice
13 questions
Recall
30 flashcards
🛡️ Safety Devices — How They Protect You
FUSE:
- Thin wire that melts if current is too high
- Breaks the circuit, cutting off power
- Common ratings: 3 A, 5 A, 13 A
- Must be on the LIVE wire (cuts the dangerous wire)
- Choose fuse slightly ABOVE normal operating current
CIRCUIT BREAKER:
- Switch that automatically "trips" if current too high
- Can be reset (unlike fuses which must be replaced)
- Reacts faster than fuses
EARTH WIRE + FUSE (working together):
- Fault occurs — live wire touches metal case
- Earth wire provides low-resistance path to ground
- Large current flows (much larger than normal)
- Fuse melts, breaking the circuit
- Power cut off before user can be harmed