3.7.7

Fuses

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Fuses and Circuit Breakers

Fuses and circuit breakers protect us from electrical appliances by stopping the flow of electric current flow if it gets too high. This stops the appliance overheating.

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Fuses

  • Fuses contain a thin wire that melts if the current flowing through an appliance is too high.
  • This breaks the circuit and stops the flow of electric current.
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Circuit breakers

  • Circuit breakers are special devices that switch off the flow of current if the current is higher than a certain value.
  • Circuit breakers do the same job as fuses but can be used lots of times.

Fuse Ratings and Circuit Breaker Settings

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

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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.

Jump to other topics

1Principles of Science I

1.1Structure & Bonding

1.2Properties of Substances

1.3Cell Structure & Function

1.4Cell Specialisation

1.5Tissue Structure & Function

1.6Working with Waves

1.7Waves in Communication

2Practical Scientific Procedures and Techniques

3Science Investigation Skills

4Principles of Science II

4.1Extracting Elements

4.2Relating Properties to use of Substances

4.3Organic Chemistry

4.4Energy Changes in Industry

4.5The Circulatory System

4.6Ventilation & Gas Exchange

4.7Urinary System

4.8Cell Transport

4.9Thermal Physics

4.10Materials

4.11Fluids

5Contemporary Issues in Science

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