ABSTRACT
Modern portable appliance testing (PAT) is more of a system for managing the safety of electrical equipment while it is in service. One mistake that is often made is to focus too heavily on the 'testing' part of this system, which actually accounts for a very small percentage of the overall process and subsequently adds only a small amount to our knowledge of the equipment's safety status. The foundation for all PAT testing should be a risk assessment, carried out by the person legally responsible for that equipment. Risk is the combination of two judgements: likelihood and consequence. In some systems actual numerical values are assigned to both likelihood and consequence; these are then multiplied together to get a 'risk score'. There are three types of in-service inspection and testing detailed in the IET Code of Practice: user checks, formal visual inspections and combined inspection and test. A well-designed PAT testing system will utilise all three.
