Electrical safety
Electricity can be the cause of accidents and fires. Some serious accidents involving electricity can be fatal and fires can be started by faulty electrical equipment or wiring.

The UK mains voltage is 230 Volts, alternating current (ac). A person receiving a shock from mains voltage can receive significant injuries, including burns, and can be killed. It is the current that does the harm, not the voltage, and a surprisingly small current flow (measured in fractions of one Amp) through the chest can stop the heart or lungs working properly.

Heat can be produced by overloaded sockets or wiring, through damaged electrical cabling or equipment or a loose connection. Some appliances give off heat, such as radiators and lighting, and these appliances can be a further cause of electricity-related fires if they are not used correctly.

Portable appliances
The term "portable appliance" can be used for many pieces of equipment that are fitted with a mains plus. This is often a 13 Amp mains plug, but some appliances are fitted with 16 Amp, 32 Amp or other industrial "CEEform" connectors. These connectors are colour coded yellow, blue and red depending on the voltage of the supply - the different colours are not interchangeable.

In general, there are a two classifications of portable appliance used on the normal mains supply, Class I and Class II. Class I appliances usually have metal casing and must be connected to an earthed supply. Class II (also known as double insulated) have two layers of insulation to prevent a fault causing an electric shock. Class II appliances are marked with the "Double Square" symbol and do not need earthing.

Portable appliances should be tested and inspected routinely by a competent person. It is often assumed that Portable Appliance Testing should be completed annually, but the frequency of the test will depends on the type of equipment and where it is used. Each appliance is usually numbered and labelled to show it has passed the test. Additionally, records of the testing and any maintenance or repairs must be kept.

The majority of faults on electrical equipment are visual, such as a damaged flexible cord or incorrectly wired mains plug or a mains plug that does not have plastic "sleeving" on the Live and Neutral pins. In addition to a visual inspection, the Portable Appliance Test includes a test that ensures the electrical integrity of the appliance. This test is performed using equipment designed specifically for testing portable appliances.