Posted by & filed under Electrical Installations, Moves and Changes, Service and Maintenance.

What is a PAT Test?

While many faults in electrical equipment can be discovered simply by carrying out a visual test, certain defects can only be detected when a PAT test is conducted. Health and Safety regulations in the UK are a driving force that recommend employers to carry out PAT tests. It’s important to realise, PAT tests are not a legal obligation in the UK.  So, what is a PAT Test?

A Portable Appliance Test or PAT Test is a test that is conducted to ensure your electrical equipment is safe to use. Generally, we refer to this process as a PAT test. However, the official term is ‘in-service inspection & testing of electrical equipment’. Time spans for testing electrical equipment can differ. It’s commonly recommended to conduct annual tests for your portable electrical devices. In addition, these tests should be done in a low-risk environment.


How are PAT Tests conducted?

To begin a PAT test, an electrician will carry out a visual inspection of the cables and the appliances. The electrician will be looking for any significant damage such as, exposed components or split cables.

Provided that the appliance passes the visual test. An insulation test is then carried out. This test measures the condition of the insulation that protects any part of the appliance that carries a current.

Lastly, an earthing continuity test is then carried out. The purpose of this test is to determine if the earthing conductors sufficient to protect users against electric shock.


How do I know which portable appliances need testing?

Technically, there law does not define exactly what ‘portable devices’ are. The definition is left to interpretation. Generally, the interpretation is that portable devices are any devices that have a plug which can be inserted into a common wall socket. On the other hand, equipment such as high-risk machinery that require inspection by an authorised electrician might not be tested during your annual PAT test. The electrical class and category of the item are generally considered to determine if the electrical equipment needs PAT testing.  Below is a list of electrical appliances that can be PAT tested:

  1. IT Appliances
  2. Handheld appliances
  3. Stationary appliances
  4. Cables and chargers
  5. Fixed Appliances
  6. Portable Appliances



Electrical classes in PAT testing

Electrical appliance classes are rated from class 1 – class 3. Class 1 being the most dangerous, Class 2 is moderate, and finally Class 3 being the least dangerous. Each class determines if the equipment requires PAT testing and if so, how much of the test must be completed. For instance, equipment that is rated as class 1 will require a full PAT test. On the other hand, equipment in class 2 requires a PAT insulation test, and equipment in class 3 does not require a PAT test.

Class 1

A combination of earth connectivity and basic installation provides two layers of protection the user of class 1 electrical appliances. Ground continuity, Instruments and insulation resistance tests are conducted when completing a PAT test for class 1 appliances.

Key points to remember

  1. Class 1 electrical appliances are made of metal.
  2. Equipment with 3 basic cables are categorised as class 1 appliances.
  3. If the plug has a metal fit, it falls into the class 1 category.
Class 2

Class 2 electrical devices are double insulated. For this reason, they do not require an earth connection when conducting a PAT test. Class 2 appliances only require an insulation resistance test. Lastly, below Is a list of key points to remember:

  1. Class 2 electrical appliances are made of plastic
  2. If the rating plate has a double box symbol. It’s a class 2 appliance.


Class 3

Class 3 electrical appliances run on SELV (separately extra-low voltage). Essentially, class 3 devices can not produce enough voltage to put the user at risk of electric shock. Additionally, the power of these devices is 50cac or 120vdc. For this reason, class 3 devices do not require a PAT test. With this in mind, if class 3 equipment has a class 2 charging lead, it might require a Pat Test.


When do I need to have a PAT test?

Commonly used items such as office equipment (printers, lamps, copiers, and radios) must be tested every 1-2 years. If fixed devices were installed correctly, they should be fine for 1-2years without a PAT test. However, certain uses have different recommendations. Schools, colleges, and universities may require frequent testing. In addition, portable devices like hand-held items at a café or tools in a factory which generally have a high usage will require frequent test. Ideally, every year or less.

The regulations can be viewed in more detail here

Advantages of PAT tests

  1. Reduce risk of electrical accidents (Fire, electric shocks, bodily injuries)
  2. Protect employees & Public
  3. Comply with Health & Safety laws
  4. Protect your business against lawsuits
  5. Improve performance in the workplace by replacing faulty equipment

Please click below to share this article