Dangers of Electricity

Electricity can be dangerous due to three reasons:  
  • Damaged Insulation
  • Overheating of Cables
  • Damp Environment
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    Damaged insulation

    Insulating materials (rubber or PVC) can become worn with time and expose the conducting wires inside.
    This would result in
    • Severe electric shock leading to serious injury or even death to the users if it is touched.
    • Short circuit if the live wire touches neutral wire or earth wire, which might result in electric fire.

    Overheating of Cables

    Overheating of cables occurs when there is an unusual large current passing through the conducting wires. 

    This is due to
    • Overloaded power sockets.  This happens when power socket is overloaded with many appliances, causing large current flowing through the wires.
    • Use of inappropriate wires. Normally, appliances require less power like bulbs use thin wires while those require more power like hairdryer use thick wires. (Note that Resistance of wire is inversely proportional to its cross-sectional area.)
    This would result in melting of insulation and electrical fire.

    Damp Environment

    In damp environment like bathing, our body is wet which cause our body resistance to drop drastically from 100 kΩ (for dry body) to 100 Ω. This allows high current to passing through our body and causing an electric shock or even death.
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