Electrical safety: past paper questions
Real questions on electrical safety
The newest 20 of 20 written questions. Open one to see it on the real paper.
- 0972/32 · May/June 2026 · Q8c[1]
The current in the heater is large. Give one reason why large currents can be dangerous.
See it on the paper → - 0972/32 · May/June 2026 · Q8d[2]
The live wire connects to a fuse which protects the circuit. Explain how a fuse protects the circuit.
See it on the paper → - 0972/32 · May/June 2026 · Q8e[1]
The current in the heater is normally 11.5A. State a suitable value for the fuse. Choose one of these values: 5A, 10A, 13A or 30A.
See it on the paper → - 0972/41 · May/June 2026 · Q8a(ii)[2]
The lawnmower circuit contains a trip switch. Explain the purpose of the trip switch.
See it on the paper → - 0972/31 · May/June 2025 · Q9d[3]
The mains plug for the router includes a fuse that protects the router. Explain how a fuse works.
See it on the paper → - 0972/32 · May/June 2025 · Q8a[1]
Suggest why a pull cord is safer than a push switch for a fan heater in a bathroom.
See it on the paper → - 0972/41 · May/June 2025 · Q4b(ii)[3]
The plug connecting the heater to the mains supply is fitted with a fuse. Fuse ratings of 3 A, 5 A, 10 A and 13 A are available. fuse explanation State which fuse is used. Explain your answer.
See it on the paper → - 0972/31 · October/November 2024 · Q10b[2]
The power supply is connected to the electrical mains by a cable that consists of three wires. State the name for each of the three wires in the cable.
See it on the paper → - 0972/31 · May/June 2024 · Q9a(i)[2]
State the name of each of the three wires inside the power cable.
See it on the paper → - 0972/31 · May/June 2024 · Q9a(ii)[1]
The cable is designed for a maximum current of 13 A. Suggest one hazard due to a current of 30 A in the cable.
See it on the paper → - 0972/32 · May/June 2023 · Q9a[3]
The desktop computer has an on-off switch in one of the wires that connect it to the mains supply. State and explain which wire includes the switch.
See it on the paper → - 0972/31 · October/November 2022 · Q9a(i)[1]
Give a reason why the plug includes a fuse.
See it on the paper → - 0972/31 · October/November 2022 · Q9a(ii)[2]
Explain how a fuse works.
See it on the paper → - 0972/31 · May/June 2022 · Q10a[4]
The microwave oven is fitted with a 13 A fuse and an earth wire is connected to the metal case of the microwave oven. A fault occurs and the live wire of the microwave oven touches the metal case. Explain how the fuse and an earthed metal case protect the appliance and the user.
See it on the paper → - 0972/41 · May/June 2022 · Q5c[3]
The metal tap is earthed and there is a fuse in the cable that connects the heater to the mains. 1. Explain how the earth wire protects the user. 2. Explain how the fuse protects the circuit.
See it on the paper → - 0972/31 · May/June 2020 · Q11a(ii)[3]
The metal case of the power supply is earthed. A fault occurs and a live wire touches the metal case. Explain how earthing the metal case protects the teacher.
See it on the paper → - 0972/42 · May/June 2020 · Q7b[2]
Another transformer is used in a school laboratory to step down a mains supply with a p.d. of 110 V to 12 V. This transformer is mounted in a metal case. State and explain an essential safety feature required for this arrangement.
See it on the paper → - 0972/41 · October/November 2019 · Q6a(ii)[1]
Suggest a suitable rating for the fuse in the heater circuit. fuse rating =
See it on the paper → - 0972/31 · May/June 2019 · Q8b(i)[1]
Draw one ring around a material that is suitable for the connection to earth. copper glass plastic rubber
See it on the paper → - 0972/31 · May/June 2019 · Q8b(ii)[1]
Explain your answer to (b)(i).
See it on the paper →
What examiners said
Many candidates scored at least partial credit for this question with clear explanations of how a fuse works. The most common errors were to use ‘voltage’ or ‘electricity’ instead of ‘current’. Many candidates did not understand how a fuse works, with explanations including, for example, regulating the voltage, regulating the current or diverting excess voltage (or current) to earth. A significant...
— Examiner report, May/June 2025, 0972/31 Q9(d) (Cambridge)
Many candidates realised that the question related to operating an electrical appliance in damp conditions. Therefore, correct answers referred either to the risk of electric shock or to the use of the cord as an insulator. Non-scientific reasons, e.g. ‘it was less far to reach’, did not gain credit.
— Examiner report, May/June 2025, 0972/32 Q8(a) (Cambridge)
Most candidates chose the 10 A fuse. Full credit here required a statement giving one reason why this was a good choice for the fuse. Many candidates gave a very full answer, explaining why each of the other fuses was unsuitable or stating clearly that 10 A is most suitable since it is slightly higher than the normal operating current. Weaker answers either demonstrated misconceptions in how fuses...
— Examiner report, May/June 2025, 0972/41 Q4(b)(ii) (Cambridge)
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