First and foremost any electrical testing is carried out to ensure that portable appliances are safe to use for the health and safety for business owner, staff and customers.  The pat testing procedures may be carried out for a number of reasons including quality assurance tests on the appliances constituent components; diagnostic testing; fault finding on appliances, equipment and plant.  Routine, pre-planned, safety checks make up the final trio of reasons why electrical testing may be carried out at a business premises.  Depending on the nature of the business premises the testing is carried out at varying intervals.  For example an office will have its equipment checked on a more infrequent basis than would a manufacturing plant.