Electricity in the Home

Mains Electricity

The electricity that powers appliances in most homes comes from the mains, usually supplied at a voltage of 230 V.
This is an alternating current (AC), which regularly changes direction and amplitude. Its frequency in the UK is 50 Hz.

Power and Energy

Electrical devices transfer electrical energy into other forms of energy, for example, heat and light.
The power of an electrical appliance is the rate at which it transforms energy, measured in watts (W).
The amount of energy an electrical appliance uses is determined by its power and the length of time it is switched on, and it is measured in kilowatt-hours (kWh).
To calculate the energy transferred by an appliance, use the formula: Energy(kWh) = Power(kW) x Time(h)

Fuses and Circuit Breakers

Fuses and circuit breakers are safety devices included in electrical circuits to prevent overloading and hence, prevent fires.
A fuse contains a small piece of wire that melts and breaks the circuit if the current flowing through it exceeds a certain value.
A circuit breaker is an automatically operated switch that interrupts the current flow in an electric circuit when it detects an overload condition.

Using Electricity Safely

For safety reasons, appliances are often earthed with a three-core cable, containing a live, neutral, and earth wire.
Appliances with metal cases, such as ovens or washing machines, are earthed to prevent the case from becoming live if a fault occurs.
Double insulation is used for appliances with plastic cases, such as hairdryers or drills, making earthing these appliances unnecessary.
It’s important not to overload sockets as it could result in overheating and potentially cause a fire.

The Earth Wire

The earth wire in a UK plug is colour coded green and yellow.
It provides a safer path (compared to through a person) for the current to flow through if there is a fault with an appliance, triggering the fuse or circuit breaker to disconnect the appliance.

Remember that dealing with electricity always involves potential risks. Always use electricity with caution, remember the safety features and refer to professional guidance and safety measures if uncertain. Understanding the basics of electricity in the home aids in a safer use of everyday’s appliances.