Conductors Insulators

Conductor

Materials that allow the movement of electrons and therefore current.

Insulator

Materials that resist the flow of electrons and therefore current.

Electrical conductivity

The ability of a material to conduct an electric current, determined by the presence and mobility of free electrons.

Free electrons

Electrons that can move freely within a material, allowing it to conduct electricity. Also known as ‘Valence electrons’

Valence electrons

Electrons in the outer shell of an atom that can participate in bonding and electrical conductivity.

Semiconductor

Materials with moderate electrical conductivity, having a few free electrons and typically four valence electrons. E.g. silicon. A semiconductor’s conductivity can be dependant on its temperature.

Examples of conductors

Materials such as aluminum, copper, brass, carbon, mercury, sodium, and tungsten that conduct electricity well.

Examples of insulators

Materials such as thermoplastics, glass, porcelain, rubber that resist electrical current.

Armouring of cables

Mechanical protection for inner conductors, typically made of steel wire.

Current-carrying capacity

The maximum amount of electric current a conductor can carry without overheating.

Environmental conditions

Factors such as temperature, water, and chemical exposure that affect cable design and materials.

Stranded conductors

Conductors made of multiple smaller wires twisted together, providing flexibility.

Solid conductors

Conductors made from a single solid wire, offering less flexibility.

Conductors usually have one to three valence electrons

True for most metals, allowing them to be good electrical conductors.

Deterioration of insulation

The reduction in effectiveness of insulation materials due to factors like ageing and environmental damage.