Fuse Ratings
Physics: Cambridge International GCSE Supplement, topic 4.10.5
Fuse Ratings and Circuit Breaker Settings
Fuses and Circuit Breakers must be chose correctly to allow correct function.
Fuse ratings
- Fuse ratings tell us the level where a fuse will begin to melt. The fuse chosen should have a value just above the normal current that an electrical appliance uses.
- For example, if the operating current is 3.9 A, and fuses with values of 3 A, 5 A or 13 A are available, the most suitable fuse is the 5 A fuse.
Power label
- Appliances in the EU have a label or panel that tells you what the power rating of the appliance is.
- This power label can be used to calculate the current required by the appliance using the equation: power = potential difference x current.
- 230 V is the potential difference across the mains power supply in the UK.
Test yourself on Fuse Ratings
Why is a 13 A fuse wrong to use for an appliance with a 3.9 A operating current?
Which fuse should you use for an appliance with an operating current of 6.5A?
What do you need to know to select an appropriate fuse for a kettle?