The Carbon Dioxide (CO2) Fire Extinguisher are designed for use primarily on electrical fires but can also be used on fires including flammable liquids such as petrol, oil, diesel and some solid fuels like wax. Fires involving electrical equipment are one of the commonest causes of fire and involve equipment, such as portable appliances, and any electrical wiring or circuitry. Electrical fires do not have an official classification in the UK, but are known as Class C in the US. Being rated as safe on electrical fires signifies that the extinguishing agent is non-conductive. It is because carbon dioxide in non-conductive that it is so suitable for use on electrical equipment, and it doesn't leave a residue behind like powder or foam extinguisher would, which would be a problem for the delicate workings of an electronic appliance. These properties make carbon dioxide fire extinguishers particularly suitable for office environments and other areas with a significant amount of electronic or electrical equipment. They should not be used on cooking oil fires as the high pressure discharge could splash the burning fat around and spread the fire further. Carbon dioxide fire extinguishers come in various standard sizes, including 1kg, 2kg, 5kg, 10kg, 20kg and 45kg. You can expect the 10kg and above types to be on wheeled trolleys as they are otherwise too heavy to be easily portable. They are usually red in colour with a black panel over the operating instructions. The extinguishers that are 5kg or larger will have a hose attached as well as the horn-shaped nozzle.