All electrical appliances using mains voltage have to provide at  least 2 levels of protection to the user. This is to ensure that if one  of the protection layers were to fail, there is the back-up of the  second layer still in place. This makes electrical equipment very safe  to use. Appliances can be Class 1 or Class 2. When PAT testing, it  is important to first identify the Class of the appliance as Class 1  appliances are tested differently from Class 2 appliances.
