Household Safety

Household electrical systems are designed to deliver electrical energy while reducing the risk of electric shock, excessive current, overheating and fire. Important protective features include: insulation; fuses or circuit breakers; earthing where required; correct wiring; * suitable appliance ratings.

Current produces heating in resistance. The heating power can be expressed as: **P = I²R** A dangerously large current can therefore cause wires to become very hot.

A **short circuit occurs when an unintended very-low-resistance path forms. From: I = VR** a very small resistance can allow a very large current. Protective devices should then disconnect the circuit.

Insulating materials around live conductors help prevent people from contacting conductors directly.

For appliances with exposed conductive cases that require earthing, the earth connection provides a low-resistance safety path if a fault makes the case live. The resulting large fault current helps the protective device disconnect the supply.

Electrical systems can be dangerous. Damaged wiring or mains electrical faults should be handled by a qualified adult/professional rather than experimented with.