Determining what needs to be PAT tested is not as difficult as it sounds. For the purpose of legislation, portable appliances include all equipment that is not part of a fixed installation but is meant to be connected to a fixed installation or generator. Any appliance that uses a flexible cable or plug and socket qualifies as a portable appliance. In other words, if you have an appliance that has a plug that is intended to be connected to a wall socket or generator, it qualifies as needing to be PAT tested.
This can include items such as electric drills, monitors, printers, PCs, kettles and larger items like photocopiers, vending machines and others. So a cordless power tool would not need to be PAT tested but their battery chargers that plug into the wall for power do need to be tested. You should note that there are larger items that seem stationary but still require PAT testing. For instance, a heated towel rail or built-in dishwasher may seem like a fixed appliance but for testing purposes, they still qualify as portable because they plug into a power source.
All IT equipment should be tested, including power cords to this equipment although they are required to be tested separately from the equipment that they power because they are held to a different standard. Electrical cable extensions are the most commonly tested items as they are among the most common sources of safety hazards.
All of your 110 volt equipment in addition to all 3 phase equipment should also be tested. If you have equipment that is not possible to turn off for PAT testing such as servers and critical systems, you should ensure that every effort is made to perform a combined inspection. Tests can be done at the next available shut down for maintenance purposes.