Fuse Ratings

Physics: Edexcel IGCSE, topic 2.1.7

Fuse Ratings and Circuit Breaker Settings

Fuses and Circuit Breakers must be chosen correctly to allow correct function.

Fuse ratings

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.

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?

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