Fuses & Earthing

• What is one of the most common problems when dealing with electricity?

  Sudden increases in current, known as surges
• What can cause surges in electrical circuits?

  Surges can occur when an appliance is turned on or off, or due to a fault in the circuit or appliance
• What are some serious consequences of electrical surges?

  They can cause fires or electric shocks
• What safety precautions can help reduce risks associated with electrical surges?

  • Fuses
  • Circuit breakers
  • Earth wires
  • Double insulation
• How do fuses and circuit breakers function similarly?

  Both break the circuit whenever the current gets too high
• What is a fuse made of?

  A very thin piece of wire connected to the live wire
• What happens to a fuse when there is a surge?

  The fuse wire heats up quickly and melts, breaking the circuit
• How are fuses typically packaged?

  In little cases with the thin wire inside
• What determines the rating of a fuse?

  The amount of current you want to break the circuit for
• If an appliance normally has a 3 amp current, what fuse rating could you use?

  A 5 amp fuse
• What fuse rating would be appropriate for a 10 amp appliance?

  A 13 amp fuse
• What is a key benefit of using fuses?

  They are simple and cheap
• What is a downside of fuses?

  They are permanently broken after a single surge
• How do circuit breakers differ from fuses?

  Circuit breakers can be reset instead of replaced
• What happens when a circuit breaker trips?

  The circuit is turned off and can be easily reset
• What is one way surges can cause harm in appliances?

  If the live wire comes loose and touches the casing
• How does earthing prevent electric shocks?

  It provides an alternative pathway for the current to flow away
• What is double insulation in appliances?

  It covers the entire appliance in a plastic casing to prevent exposure to metal parts
• When is an earth wire not needed in an appliance?

  When the appliance has double insulation
• What two wires does an appliance with double insulation typically have?

  A live wire and a neutral wire
• What are the main safety measures to prevent electric shocks and surges?

  • Use of fuses
  • Use of circuit breakers
  • Implementation of earthing
  • Application of double insulation