What You Need to Know About Portable Appliance Testing

PAT training course

What is PAT Testing?

Portable appliance testing also known as PAT or PAT testing is a term used to explain the examination of electrical appliances and equipment to ensure they are safe to use. 

PAT is the name given to a series of inspections and electrical tests carried out on portable equipment to ensure they can be used safely. It is more accurately known as the inspection and Testing of In-service Electrical Equipment.

It usually includes three steps:

  1. Regular, informal checks by electrical equipment’s user(s)
  2. A formal visual inspection of the equipment
  3. A manual examination of the equipment with a portable appliance tester device (the PAT test)

PAT testing is vital for business owners and those accountable for any premises. Most electrical safety defects can be found by visual inspections, but some types of defects can only be found by testing.

However, it is necessary to understand that visual examination is an integral part of the process because some types of electrical safety defects cannot be noticed by testing alone. 

This blog post is a thorough explanation of what PAT testing is, what requires PAT testing, what is involved in the process and how often one needs to conduct a PAT test.

What Requires Portable Appliance Testing?

There is a common misconception that PAT is just equipment that can be plugged in, but it is a bit more complex than that.

The IET Code of Practice breakdowns it into several categories:

  • Portable equipment appliances – Easy to move while in operation, for example, Kettle, Toaster, etc.
  • Hand-held appliances – These are portable and by design require the use of direct hand contact – e.g., Hair clippers
  • Fixed appliances – These are the items that are permanently fixed in place when installed, for example, the Pillar drill

Along with the different types of electrical equipment, there are different classes of electrical equipment as well. 

There are usually five classes of equipment, but for this blog three are discussed that are mainly encountered.

  • Class 0
  • Class 01
  • Class II
  • Class III
  • Class IV
  • Class V

Class I – This type of equipment relies on the basic insulation of live parts to prevent contact with the parts that are live under normal conditions. Kettles and electrical fan heaters are perfect examples of Class I equipment.

Class II – This type of equipment either relies on double insulation or reinforced insulation to protect the user from a fault. Garden equipment like strimmer is an example of Class II equipment.

Class III – This type of equipment is supplied from SELV (Separated Extra Low Voltage) source, which will not exceed 50 AC (Alternate Current). Class III equipment does not require PAT testing; however, its associated charging equipment may require so. Laptops, PCs and Mobile phones are an example of Class III.

Is PAT Testing a Legal Requirement?

There are no specific PAT testing regulations or obligations that exist. It is not a legal requirement to undertake PAT testing. However, the law states that businesses must maintain electrical equipment in a safe way condition and employers must ensure that their electrical equipment is safe for use.

Regularly conducting PAT is the best practice to ensure safety at work. Employers can also offer suitable PAT testing course to their staff to make them familiar with best practices and well as safe ways to conduct the work.

What is Involved in Carrying Out a Portable Appliance Test?

The process of carrying out a PAT test involves three steps:


The first step is the documentation. It is often a neglected part of portable appliance tests. The first piece of documentation that is obligatory is a list of all the electric equipment that is held by the company. It should list:

  • The name of the equipment
  • Equipment number
  • Location
  • Class of equipment
  • Date of previous & next PAT test

This information helps individuals performing tests, to locate and identify the equipment. 

Visual Inspection 

Visual inspection should take place before electrical testing. There are certain things one must check wherever and whenever possible:

  • Signs of noticeable damage to the equipment
  • Signs of thermal harm to the equipment 
  • Any signs of visible & thermal damage to the leads
  • Any signs of visible & thermal damage to the plug
  • The correct size of the fuse must be installed


There are numerous choices when it comes to selecting the test equipment for Portable Appliance Testing. But it can mainly be categorized into two types:

  • Dedicated PAT Testers – It comes in a variety of types and levels of complexities. More precisely, it is a pass or a failure test that tells the users whether the equipment is passed or failed.
  • Separate Test Equipment – It can be used to perform portable appliance testing; this can be either a separate Earth continuity test or a separate insulation resistance tester.

How Often do You Need a PAT Test?

As there is no specific law about PAT testing, so does not have a frequency for when it must occur. The IET Code of Practice states that the responsibility of undertaking a PAT test falls on the duty holder responsible to ensure the workplace safety of their staff or anyone else on the premises.

The following factors must be taken into consideration before conducting a risk assessment for PAT testing:

  • Working environment
  • Types of equipment
  • If the equipment has been modified or repaired recently
  • If any problems have been identified


This post is an in-depth explanation of what everyone needs to know about Portable Appliance Testing. It explains what PAT testing is, what requires PAT, and its types and classes. It further explores the legal requirements and the process of undertaking a PAT process.

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