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In-service Inspection and Testing of Electrical Equipment (ISITEE) or commonly known as Portable Appliance Testing (PAT Testing) is required to ensure that you are providing safe electrical equipment to your workforce / members of the public.


It is not mandatory to test personal items however, if your polices and procedures allow for such items in the workplace then you can insist they are tested to make sure they are safe to use on your premises.  Durham Electrics is able tooffer advice on this subject if you are a small business looking for further guidance.


Some companies over pat test their equipment and others do not do enough. Here are some typical examples of what pat testing periods you could adopt;



There is often little movement in office equipment once installed. Depending on other parameters you could test your equipment between 2-4 yearly. The majority of offices in the region test every 2 years with visual inspections carried out in alternate years.  If you have a high staff turnover your company policies and procedures may indicate a need for annual full testing to capture equipment that may have been missed.  


Hotels / Restaurants

Where you supply services to the general public you must be able to demonstrate that you are conducting suitable and sufficient testing.  Hotel accommodation will have a higher usage and should therefore be tested more frequently than in an office. With this in mind it is recommended to test your equipment at least annually.


Kitchens / Bar Areas

High usage equipment will need to be tested at least annually.


What does PAT Testing involve

It involves checking all portable appliances to make sure they are safe to use.  PAT testing involves switching off appliances and removing the plugs and opening plugs to check it is wired correctly with tight terminals. Durham Electrics replace fuses where required.


The procedure for PAT testing isn’t as straight forward as you would expect.


Stage One: visual

All items are visually inspected which includes:

  •  Checking the lead, plug and external casing

  •  Checking additional external features

  •  Opening the plug and checking the fuse and connections


Stage Two: testing

Providing the item passes the visual inspection the electrical testing will be completed. The testing involves a competent person using either a dedicated PAT-tester or electrical tester to ensure the item is electrically safe. The classification of the item of equipment been tested will determine which tests are required.

  •  Earth Continuity

  •  Insulation Resistance

  •  Polarity

  •  Functional test


When the items have passed both stages one and two Durham Electrics will then deemed the findings as satisfactory. Pass or fail stickers will have been applied to equipment. The completion certificate will then be issued.


PAT Testing Certificate

Durham Electrics operates an electronic certification system. Your certificate will be submitted on completion of paid invoices.  As with electrical testing and inspection reports an admin fee will apply to hard copy certificates.


Server Rooms

Server rooms are sensitive areas in the workplace and switching off this equipment can and will lead to significant down time for a company.  Durham Electrics utilizes thermal image camera’s to check for hot spots.



Equipment Classification

You may have seen or heard references such as class I or class II equipment but what does this mean and how does it relate to PAT testing.


Class I (Earthed Equipment)

Class I equipment relies on metallic parts being earthed. Where the earth is broken the equipment can become ‘live’ causing potentially fatal results.

Fact: Class I appliances rely of safe building electrics for full protection.

Class II (Double Insulated Equipment)

All Class II appliances are indicated by a double box symbol on the rating plate.  

Only the insulation resistance test is carried out for Class II appliances.


  •  All appliances with a fuse in the plug are Class I

  •  Appliances with a plastic case are Class II

  •  Appliances with three-core cables are Class I

  •  Only Class I appliances have metal Earth pins.

A competent person will always check the rating plate in the first instance for identification.

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