ABSTRACT

This chapter examines why inspection should precede testing, and explains the types of test equipment. It talks about the reason for carry out 'earth continuity' tests, 'insulation resistance' tests, and 'flash/dielectric strength' tests. In some low-risk environments such as offices, shops, and hotels, Class II equipment does not require the routine instrument tests. Testing has to be carried out with the appliance/equipment isolated from the supply. The isolation is easy when the item is supplied via a plug and socket, but presents some difficulties if it is permanently wired to a flex outlet, a connection unit, or an isolator. Portable appliance testers are designed to allow operatives to 'plug in' an item of equipment, push a test button, view results and note a 'pass' or 'fail' indication. Some testers have the facility for testing appliances of various voltage ranges, single and three phase, although the majority only accept single-phase 230 or 110 V plugs.