Every business needs to plan its PAT testing schedule properly, and while every portable appliance used by the business needs to be tested, it is important to classify this equipment properly so that each appliance receives the correct level of testing. This classification effectively relates to what is a Class 1 and what is a Class 2 appliance, and ensuring this classification is carried out properly removes the possibility of the incorrect testing being applied and potential safety hazards and performance issues remaining undetected.
What is a Class 1 appliance in PAT testing?
A class 1 appliance relies on both basic insulation and an earth connection as a safety feature, and therefore protects the user from an electric shock by not relying on basic insulation alone. This means there should be a visible earth connection (usually a green and yellow wire) and a connection to a protective conductor in the fixed wiring of the plug for the supply cable. As a result of this earth connection, if the basic insulation of the appliance fails, the user is protected by a safe path to ground for the fault current. Otherwise, the metal components of an appliance could become live conductors.
In terms of a PAT testing programme, appliances identified as Class 1 require a full testing regime, which means a full visual inspection, an earth continuity test, insulation resistance testing and a polarity test. The appliance should also have its functionality tested to ensure it is operating correctly. Class 1 appliances are generally those which have a metal casing and which rely on an earthing connection for safety, so this could be a fridge, freezer, a kettle, a toaster or a washing machine.
What is a Class 2 appliance in PAT testing?
Class 2 appliances are very similar to Class 1 appliances, in that they protect the user against electric shock by not relying on basic insulation alone. But in this case, class 2 appliances use supplementary insulation rather than an earth connection. So class 2 appliances have double or reinforced insulation and therefore only have two wires in the plug (a live and a neutral wire) and will have no earth wire and no earth connection. The power supply will be via a two-core cable.
In a PAT testing programme a class 2 appliance will only require a full visual inspection, an insulation resistance test, to ensure that this supplementary insulation is working correctly, as well as the obligatory functional tests to establish that the appliance is operating as it should be. Class 2 appliances generally have a plastic casing and are designed to be double insulated, so this would include most laptops, printers, photocopiers and power tools.
Order your PAT testing equipment from Test Instrument Solutions
Class 2 appliances are considered to be safer, because of this double insulation, so it is important that your appliances are classified correctly, because if a Class 1 appliance didn’t undergo the full range of testing, then a safety or performance issue may not be identified and hence a hazard will always exist until it potentially causes a serious incident. Therefore, to make your PAT testing programme effective, you should carefully classify all the items in your PAT testing itinerary.
Most PAT testers, including the TIS 600 and the TIS 700 supplied by Test Instrument Solutions, will have selection modes for Class 1 and Class 2 appliances clearly indicated. So check out our range of PAT testing equipment and order online from Test Instrument Solutions today.
Product Demonstration Video
Below is a product demonstration video for the TIS700 PAT tester: