Appendix – Some Electrical Definitions

This short appendix will introduce you to the basics of electricity as it relates to domestic properties


What is electricity?

Electricity is a form of energy which is derived from the basic atomic structure of materials.

You can use the internet to research atomic structure and how protons, neutrons and electrons affect electrical charge, but in this short introduction, that is too much detail. We are interested in practically how electricity applies to our properties.

Electricity becomes interesting to us when it moves through wires and cables to power lights and equipment.

Electrical Terms


Any material through which electricity can move is known as a Conductor. Some materials are better conductors than others. For instance plastic is not a good conductor, copper is a good conductor.

Plastic and copper form the basic method by which electricity is made available to lighting and equipment. A wire or cable is made up of one or more copper cores through which the electricity flows and plastic covering, known as insulation, which protects the copper cores.


The flow of electricity through a conductor is known as the Current. Electrical current is measure in Amps (actually it is really known as Amperes after an 18th Century French mathematician).


Voltage is a type of electrical force and is measured in Volts (named after an 18th Century Italian physicist). Electricity is supplied to UK domestic properties with a ‘force’ of 240 Volts.


Watts are a measure of power. It is how much electrical energy used by the lighting or piece of equipment which is being powered. Watts are named after another 18th Century scientist, this time a Scot, James Watt.

Watts are calculated mathematically by multiplying Current by Volts.

W = V x A

Electrical Equipment

Domestic electrical equipment consumes different amounts of power depending on the function of the equipment.

Some examples

  • an electric bulb providing enough light to illuminate a room, might be consuming 60 Watts
  • an electric kettle heating water may be consuming 2000 Watts
  • a cooker with four rings and an oven with all of them on, might be consuming 10,000 Watts.

All of these, including the light bulb use a lot of power.

A pedal powered generator, good in theory but doesn’t work in practice

To make a comparison, a champion cyclist would rarely generate more than 400 Watts over a sustained period; an ordinary cyclist might be producing a continuous 50 Watts. Bradley Wiggins at full pace, could not produce enough energy to make a cup of tea and the rest of us could barely power a light bulb.

Such comparisons helps us to understand the enormous power of electricity and how such power is capable of causing harm and presents a hazard to be managed.

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