Testing and Tagging is a process of checking, testing and then tagging (labelling) electrical appliances, and is usually done in the workplace to reduce risks to your employees. Test and tag keeps insurance premiums low and also if you've had it done then your insurance can't use negligence as a reason for voiding any insurance claims related to electrical fires etc.
A record of your regular test and tag is kept as part of a company's OH&S risk management process documentation.
Other names for test and tag include Tag Testing, PAT Testing and Safety Tagging.