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Portable Appliance Testing
Overview - Tests - Definition
Portable Appliance Inspection and Testing, or PAT Testing as it is sometimes referred to, is an important part of any Health
& Safety policy. If your working environment has any electrical appliances with a plug attached then these are classified as
Portable Appliances. Some examples are shown on this page. To minimise the risk of a potential fire risk or the risk of an
electric shock to either the employee or the general public, or for insurance puroposes, it is important to have these appliances
safety tested to promote a safe working environment.
The legislation of specific relevance to electrical maintenance is outlined in:
- Health & Safety at Work Act 1974
- The Electricity at Work Regulations 1989
- The Management of Health & Safety at Work Regulations 1992
- The Provision and Use of Work Equipment Regulations 1992
The purpose of the Electricity at Work Regulations is to prevent death or injury to anyone from any electrical cause as a result
of, or in connection with, work activities. For example, the act quotes: "As may be necessary to prevent danger, all systems
shall be maintained so as to prevent, so far as is reasonably practicable, such danger."
The Health and Safety at Work Act 1974 puts on employers a general duty of care to their employees. Specifically it quotes:
"It shall be the duty of every employer to ensure, so far as reasonably practicable, the health, safety and the welfare at work
of all his/her employees."
"The employers duty includes the provision and maintenance of plant and systems at work that are, so far as is reasonably practicable,
safe and without risks to health........."
The above legislation is just a small example of what is required. It clearly identifies the importance of providing safe electrical
equipment within the workplace. Portable Appliance Testing ensures all electrical portable equipment is safe to use at time
of testing.
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Formal Visual Checks
Te code requires that in addition to user checks, formally documented visual checks are routinely carried out.
Earth Bond Test
Classs I euipment normally conducted from 6A to 25A. This test is for checking the integrity of the resistance of the safety
earth connection.
Earth Screen Test
Used to test IT equipment (e.g. computers, copiers, etc.) which require a low earth "screen" current of 100mA
(Sometimes called Business Equipment or I.T. Test). This is to prevent damage to the equipment.
Insulation Test
For Class I and II appliances, this is normally conducted at 500 VDC, with option of appying a 250V test where mains input
filters might give misleading readings.
Earth Leakage Test
For Class I and II appliances, used where insulation testing is not recommended. The current flowing into the appliance via
the supply cable is compared to that flowing out. Any difference must be leaking to earth, either via the earth lead (Class I)
or the case or other connection (Class II).
Flash Test
This is a very severe test and can cause damage to equipment. Flash tests are normally only carried out to equipment that
has been repaired or sustained damage.
Inspection
Formal documented visual checks are carried out by experienced qualified engineers. These inspections include checks for
safe wiring, condition of cable/flex, correct fusing and any sign of overheating, damage or incorrect operation.
Test Equipment and Callibration
Only when the test engineer is satisfied with the visual checks, is the appliance connected to the test equipment. Modern
computerised Portable Appliance Test (PAT) Equipment is used for testing. This equipment is capable of carrying out all the
tests necessary under the Code Of Practice. The equipment used is regularly callibrated and is also checked for
accuracy before every testing session.
Disonnecting Computers and Sensitive IT Equipment
Equipment to be tested normally has to be disconnected from the mains supply. We can, however, test certain IT equipment
(Servers, etc.) without disconnection, thus avoiding any of the potential problems associated with re-booting. Any equipment
that is connected at the time of the test is only disconnected after permission to do so is obtained from the user or a department
manager. This is particularly important in the case of IT equipment and security cameras etc.
Fault Rectification
Equipment will not be failed because of faulty plug-tops or incorrect fuses. These will be replaced automatically before
testing, for a small charge. Other repairs can be carried out on-site. Estimates will be supplied.
Labelling and Identification
All appliances and cord-sets are labelled and given a unique ID. This enables us to track test results over the long term, and
make sure that tests are carried out without fail at the approproate intervals. In addition, PASS or FAIL labels are affixed to
the tested appliance, with the test date, the re-test due date, and initials of the test engineer. The labels are affixed in a position
where the user can see at a glance the status of the equipment. If required, we can supply labels to your specification.
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DEFINITION OF PORTABLE APPLIANCE
A Portable Electrical Appliance is defined as any electrical equipment which is powered between 40 and 240 Volts and which
is connected to the electrical mains via a flexible cable/plug and socket (usually a 13 Amp outlet). It does not imply that the
appliance is readily portable, only that it can be moved without unwiring.
Portable Electrical Appliances brought to and used in the workplace. This policy applies to such appliances as if they were
the property of the business.
Portable Appliances are not just specialised pieces of electrical equipment that require testing routinely.
They include everyday appliances such as:
Visual Display Units; Computers; Kettles; Hand Drills; Photocopiers; Fridges; Mobile Phone Chargers; Vacuum Cleaners;
Televisions; Video Recorders; Musical Instrument Amplifiers & PA Systems; Heaters; Church Organs and even PAT Testers!
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