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Mains power supply

The electrical circuit that supplies electric power to homes is the mains power supply.

In the UK, Europe and Singapore, the mains supply is $$230\text{ V}$$ A.C. current with a frequency of $$50\text{ Hz}$$.

Electrical appliances are connected to the mains power supply in parallel. This means that the same voltage is supplied to each appliance.

The mains power supply is made up of two wires that connect the home and the substation:

  • The high-voltage ($$230\text{ V}$$) live wire carries current into the home.
  • The zero-voltage ($$0\text{ V}$$) neutral wire carries current out of the home.

When electrical appliances are plugged in, they are connected to a live wire and a neutral wire, creating a complete circuit. This allows current to flow through the appliance from the live wire to the neutral wire.

The mains power supply is made up of the live wire (brown) and the neutral wire (blue).
The mains power supply is made up of the live wire (brown) and the neutral wire (blue).