Portable Appliance Testing

Portable device testing (commonly known as "PAT", "PAT inspection" or (redundantly) "PAT test") is the term used to describe the examination of electrical devices and equipment to ensure that they are safe use. The official term for the process is "in-service inspection and test of electrical equipment". Most electrical safety faults can be detected by visual examination, but certain types of faults can only be detected by tests. However, it is essential to understand that visual examination is an essential part of the process since some types of electrical safety faults cannot be detected by testing alone.
It is a myth that all portable electrical devices in a low risk environment, such as an office, must have a portable device test (PAT) every year. The law simply requires employers to ensure that electrical equipment is maintained to prevent hazards - it does not specify what needs to be done and how often.
The frequency of inspections and tests depends on the type of equipment and the environment in which it is used. For example, a power tool used on a construction site should be examined more frequently than a lamp in a hotel room. For advice on suggested inspection and test frequencies, see: Maintenance of portable appliance equipment.

How The PAT Test Done?
Visual examination
Visual examination is vital and always precedes electrical tests. It often reveals major faults which would not be revealed by tests alone.
The categories of visual examinations and in-service electrical tests are divided into three types:

1. Operator Controls (no recording if the equipment is OK).
All equipment users should understand the importance of operator controls. Some equipment and environments may require special needs, but generally the following list is a typical checklist that operators should use.

Check the condition of the device / equipment (check for cracks or damage).
Examine the cable powering the item, looking for cuts, abrasions, cracks, etc.
Check that the cable sheath is securely fixed in the plug and the device.
Look for signs of overheating.
Check that it has a valid label indicating that it has been formally inspected and tested and the date of the next inspection and / or test.
Decide if the item is suitable for the environment in which it is to be used, for example, 230 V devices should not be used on a construction site, unless they are protected by a 30 mA RCD.
If all of these checks are satisfactory, check that the device is working properly.
2. Formal Visual Examination (recorded)
Check the length of the cables to ensure that the cables will not be damaged by personnel or heavy equipment.
Make sure that plugs, sockets, flexible sockets, insulators, etc. are always accessible to allow disconnection / isolation of the power supply, whether for functional, maintenance or emergency purposes. For example, in many office environments, electrical outlets are very often hidden by filing cabinets.
Check that items requiring clear ventilation, such as convectors, VDUs, etc., are not covered with paper, files, etc., and that foreign objects or moisture cannot accidentally get into a such equipment.
Make sure the cables coming out of plugs or equipment are not bent well.
Check that the multi-channel adapters / extensions are not used excessively.
Check that the equipment is suitable both for its destination and for the environment in which it is used.
Make sure that accessories / equipment are disconnected from the power during the inspection process, either by removing the plug, or by turning them off at a connector unit or isolator.
Be very careful before isolating or switching off professional equipment. Make sure that a responsible person accepts that it can be done, otherwise it could cause serious loss of information, work process, etc.


3. Visual Examination And Combined Electrical Tests (recorded):
At regular intervals, portable devices are tested to measure the degree of protection to ensure that it is adequate. At these intervals, a formal visual inspection is performed, followed by a PAT test. Note that the inside of the plug should be checked unless it is molded or there is an unbroken seal covering the screws (improper internal wiring or an improper fuse would classify the item as dangerous).
The frequency of visual examinations and electrical tests depends on a number of factors. There is no strict test schedule. If the cable passes your visual inspection, use a standard test lead (included with most PAT testers) to perform the following test procedures:
Earth bond / continuity test
The earth bonding / continuity tests only apply to class I equipment and are used to confirm the existence of a safety return path. The purpose of the test is to ensure that the ground terminal has a low resistance connection to the conductive metal housing of the device. An efficient connection to the system earth within the fixed installation of the premises guarantees safety. There are two methods available and different circumstances will require each method:Home