Power Surge

• Circuit breakers are designed to automatically switch off if there is a fluctuation or surge in the electrical supply. If more power enters the circuit than the gauge of the electrical wires can hold, the cable will heat up and potentially cause a fire. This will ultimately break the circuit, but not before an electrical fire has possibly endangered lives and property.
  
  

Short

• An electrical short is when the flow of electrical current in a circuit takes an unintended route to ground, instead of traveling back through the neutral wire. This can happen when a terminal screw loosens and the live wire touches the metal switch or outlet box. If a person touches the box, the electricity takes the path of least resistance through the person's body, giving him a shock. A circuit breaker is designed to switch off in this instance, but if it malfunctions, a person touching a shorted outlet or switch is potentially at risk.
  
  

Overheated Circuit

• As each circuit breaker is rated with the maximum number of amps it will allow the circuit to use at any one time, if it malfunctions more amps may be used than the gauge of the electrical wire can handle. As with the power surge, the wire heats up and may cause a fire. Ultimately the electricity will cease when the wire melts, but prior to this it could endanger lives.
  
  

Shocks

• Circuit breakers are constructed to automatically switch off when a foreign object touches a live wire. If the breaker is faulty, the wire will remain live, causing an electric shock to anyone touching the wire or a metal implement like a knife that is touching the wire.