Why is the Class of an appliance important? An electrical appliance is categorised by a class ranking system which is based on the products electrical output and whether its user has been sufficiently protected from shocks by means of an earthing cable or insulation. The first two categories apply to appliances that should not be in use:
Products that are Class 0 features a single level of insulation which unfortunately means that 1 fault could cause an electric shock to its user or at the very least cause a spark that can easily escalate to a fire. Such products were intended for use in very dry areas and have been banned in the UK since 1975. Before this category was banned Christmas tree lights were quite frequently a Class 0 product.
Similar to 0 but has a power supply cord with no earthing conductor. The plug itself has no earthing contact. Class 01 products are often specialist equipment and are not for common everyday use.
Items in this class have an earth circuit built in and an earth wire in the plug. Metal parts of the products could potentially cause a hazardous voltage if the basic insulation fails. This basically means that all metal parts of the products need to be earthed via the protective conductor. A Fault in the appliance should trip and overcurrent device like a fuse or circuit breaker protecting the end user. Kitchen appliances are good examples which means they all need to be PAT Tested:
Kettles, Irons, Washing Machines, Toasters, Microwaves, Electric Heaters, Fridges, Freezers and Tumble Dryers.
These products will have no earth circuit and no earth wire in the plug. Class 2 products are commonly known as ‘double insulated’. This is intended as an additional precaution against electric shocks. These products also need to be PAT tested and good examples include:
Hairy Dryers, Garden Power Tools, DVD Players, TV’s and Lamps.
Appliances that operate at SELV (Separated Extra Low Voltage) are deemed to be class 3. This basically means the device cannot produce enough voltage to risk the user getting an electric shock. Generally, the power output of these items is 50vac or 120vdc. PAT testing isn’t required on Class 3 products but their charging leads, for example, could be a class 2 and therefore need to be PAT Tested. The following items are typically Class 3 appliances unless they are for medical use which means they are not deemed to be sufficiently protected:
Mobile Phones, Laptops and Low Energy Light Bulbs.
