ElectricityDeep Dive

Choosing the Right Fuse

Part of Mains Electricity & Safety · GCSE GCSE Physics revision

This deep dive covers Choosing the Right Fuse 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 6 of 16 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 6 of 16

Practice

18 questions

Recall

30 flashcards

🧮 Choosing the Right Fuse

Step 1: Calculate normal operating current using I = P / V

Step 2: Choose fuse rating just ABOVE this current

Example: A 2000 W kettle at 230 V:

I = P/V = 2000/230 = 8.7 A
Available fuses: 3 A, 5 A, 13 A
Choose: 13 A (next size up from 8.7 A)

Why not 5 A? Normal current (8.7 A) would blow it immediately! Fuse must be above normal current but below dangerous levels.

Keep building this topic

Read this section alongside the surrounding pages in Mains Electricity & Safety. That gives you the full topic sequence instead of a single isolated revision point.

Double Insulation How It Works: Why AC Peaks at 325 V But We Say 230 V Why the Earth Wire Saves Lives UK Mains Supply — Key Facts

Practice Questions for Mains Electricity & Safety

What does AC stand for, and how does it differ from DC?

A. Alternating current; it flows at a higher voltage than DC
B. Alternating current; it repeatedly changes direction, whereas DC flows in one direction only
C. Adapted current; it is produced only by batteries
D. Alternating current; it flows at a constant rate, whereas DC changes direction

1 markfoundation

Explain how a fuse protects an electrical circuit from damage.

2 marksstandard

Quick Recall Flashcards

What is DC?

Direct Current — current flows in one direction only (batteries provide DC)

What is AC?

Alternating Current — current direction reverses constantly (50 times/second in UK)

18 questions on Mains Electricity & Safety — practise free

Instant marking, adaptive difficulty, and 30 spaced repetition flashcards. Free until your GCSEs.

Try PrepWise Free

Double Insulation

How It Works: Why AC Peaks at 325 V But We Say 230 V