What is PAT testing?

By Alex Miller / 11/08/2016 / Electrical

City & Guilds 2377 logoFirstly, the traditional name is PAT Testing, not PAC Testing or PAK Testing – although all are made-up terms.

Although the name suggests that PAT Testing is to do with testing something, there is a lot more to it than that.  Firstly we need to understand what PAT Testing actually relates to.

Over the years, the term ‘Health & Safety’ has entered virtually every part of our lives in the UK.  In order to keep people safe in the workplace, employers are responsible for ensuring all work activities can be carried out without risk to their employees, visitors, customers – in fact anyone on their premises.  To help employers to understand what their responsibilities are, there have been a number of Laws, Acts of Parliament and Regulations developed over the years.  These ensure that everything is considered and all employers abide by the same set of information to produce consistency.

One such area relates to electricity in the workplace.  As electricity can be life threatening it is closely managed,and all activities involving electricity are governed by the Electricity at Work Regulations 1989.  Whether we are talking about the fixed installation (light fittings, socket outlets, mains wiring etc) or electrical equipment (computers, vacuum cleaners, desk fans etc), their safe usage has to be considered at all times.

Whilst the electricity in the fixed installation and electrical equipment work in the same way, there are different maintenance requirements, so they tend to be looked after by different people.  The fixed installation is normally maintained by an electrician, whereas the electrical equipment is inspected and tested by a ‘PAT Tester’.  The work which is carried out in both cases is broadly the same, although there is a difference in scale and complexity.

From this point onwards, let us concentrate on PAT Testing and leave the fixed installation to the electricians.

In-service Inspection & Testing of Electrical Equipment

As most people refer to typical work equipment as ‘portable’ (due to its size and portability), maintenance of work equipment has been known as Portable Appliance Testing, or PAT Testing for many years.  In a way, it’s like calling a vacuum cleaner a ‘Hoover’ when in fact it may be a Dyson.  It has become a generic name.

In reality, not all electrical equipment is ‘portable’ and our role involves more than just ‘testing’, so we should really use the full name for the role – In-service Inspection & Testing of Electrical Equipment.  Although it is a much larger and unwieldy name, it is much more descriptive and suitable.

If we break the name down it gives us a better understanding of what the role entails:

In-service – The equipment is in use, as opposed to electrical equipment which may be on the premises as stock items for sale

Inspection – Before equipment is tested for electrical safety it should be inspected for damage, missing parts, added parts, equipment information (power, appliance classification, voltage, ingress protection rating, suitability of use, statutory symbols), damage to the plugtop & flex, suitability of the fuse, British Standard numbers etc

Testing – Once equipment has passed a Formal Visual Inspection it can be tested for electrical safety.  This normally involves putting the equipment through a series of electrical tests using known currents and voltages, and taking test results.  These results are compared to known values to determine whether specific safety features built into the equipment will perform if there is a fault situation.

Electrical Equipment – As we have already identified, not all electrical equipment is portable.  In fact we can break equipment down into several different ‘appliance types’ based upon how often they are moved, their size and the proximity of the equipment user to the equipment.  For example, a drill is classed as hand-held as the user holds it when it is in use, whereas a fridge is classed as stationary as it doesn’t move.  These different appliance types will help us to determine the potential risks attached to the appliance, and how often we need to carry out inspections and tests on the equipment.

The PAT Testing Process

PAT Testing is relatively simple, but in order to carry it out correctly the PAT Tester must be organised, disciplined and be able to follow a process.  We can teach the technical side of PAT Testing, but we can’t change a bad attitude.

Environment Check

This is to do with the safety of the PAT Tester and also the safety of the user.  Upon entering the room, a PAT Tester should have a good look around at the overall safety of the environment.  For example, is the equipment being used for its designed purpose? Is the user using it safely? Are there trip hazards? Is there a moisture problem (dry appliances being used in a wet environment)? Is there sufficient space for the PAT Tester to carry out their role safely? Is there excessive use of trailing sockets and extension leads? Is there a high concentration of people? Are there any potential hot spots or fire hazards? Etc

To help with this process, it is good practice for the PAT Tester to carry out a Risk Assessment before they start work, and report their findings to the Responsible Person or Duty Holder of the site.

Formal Visual Inspection

As outlined above, an inspection of the appliance will help to identify any physical abnormalities.  Whereas some may be put down to wear and tear and don’t affect the safety or functioning of the appliance, some could be an accident waiting to happen.  On average, 90% of appliances which fail a PAT Test do so because of a good Formal Visual Inspection.

This part of the PAT Testing process can take time, so you need to be realistic if you decide to set testing targets.  The national average set by many PAT Testing companies is around 200 appliances per day.  If the role is being completed properly and thoroughly, 200 is a ridiculously high figure.  Of course it does depend upon many factors, but a good guide is probably nearer the 100 mark.  PAT Testers often get paid per appliance, so the more they do, the more they get paid and the more corners are cut.

To help our trainees we have developed a FVI (Formal Visual Inspection) checklist which outlines the points which need to be checked on every appliance.

Electrical Tests

The FVI checks the outside of the appliance and roughly speaking the Electrical Tests check the inside.  There are a number of compulsory tests which have to be carried out (depending upon the class of the appliance), and a selection of tests which are classed as optional.  There is nothing wrong with carrying out the full range of tests, but most of the PAT Test devices only feature basic test sequences.

The electrical tests are designed to stress and measure the effectiveness of safety features which have been built into the appliance by the manufacturer.  As with most things, appliances will deteriorate with age and use, so they are tested on a regular basis.  The frequency of testing is to be determined using a risk based approach, and is down to the customer NOT the PAT Test company.

Functional Check

Before an appliance can pass its PAT Test, it must be checked of functionality.  This normally involves plugging the appliance into the mains supply and making sure it works and that all of the controls function.

It is very common for an appliance to pass the Formal Visual Inspection and electrical tests, but doesn’t work due to an internal component problem.  The electrical tests are designed to look at specific parts of the appliance and will not pick up on broken or faulty components, so a simple function check will do the job.

Interpreting, Recording and Labelling

After the inspection and tests, the results need to be interpreted by the Inspector (you!) to determine if the appliance has passed or failed.  Although this information doesn’t need to be recorded, it is good practice in case of any future incident and investigation. The appliance can then be labelled.  Again, it’s not a legal requirement to label the appliance, but it is good practice and shows adherence to set routines (if done with care).

Source: http://www.priorytrainingacademy.co.uk/what-is-pat-testing.html

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