Without proper care, maintenance and regular reviews, electronic equipment can pose a real threat. Over time, the efficiency and condition of electrical equipment will decrease: think of it as wear and tear, in simpler terms. Because of this, it is crucial to conduct regular maintenance checks – done by an expert – to ensure that the equipment is running correctly and safe to use.

This guide will allow you to understand the different PAT testing classes and why it is critical to conduct PAT testing accurately and efficiently.

As electronic equipment becomes more prevalent within our daily lives, the importance of PAT testing is crucial.

What is a PAT Test?

Defined as Portable Appliance Testing (PAT), it is a routine inspection or examination of various types of electrical equipment and appliances to determine if they are safe to use: this is to prevent accidents or harm to humans, animals and property in the workplace.

Though many defects of electrical equipment can be visually determined, PAT testing also involves a cable inspection using specialist PAT testing tools. The full PAT test is simple to break down:

  1. Visual inspection of the electrical appliance
  2. Cable inspection – using PAT testing equipment

The cable inspection portion of a PAT test will include checks and confirmations of the earthing continuity, lead polarity and the integrity of the insulation resistance.

The definition of PAT can be somewhat misleading, however, particularly the word “portable”: appliances that fall under PAT can be any appliance that has a plug attached to connect it to a wall outlet.

There are three distinct classes of electrical appliances: Class 1, Class 2 and Class 3. Class 1 devices are the most dangerous and require a full PAT test.

What Falls Under PAT?

There are seven categories of electronic equipment that fall under PAT testing:

  • Cables and chargers – mobile phone chargers, laptop chargers etc.
  • Fixed appliances – storage heaters, hand dryers, machine tools etc.
  • Handheld appliances – hair dryers, drills, irons etc.
  • IT equipment – computers, printers, photocopy machines etc.
  • Moveable appliances – toasters, kettles, DVD players, televisions, game consoles etc.
  • Portable appliances – laptops, wireless landline phones etc.
  • Stationary appliances – fridges, washing machines, clothes dryers etc.

The interpretation of portable under PAT testing is broad, meaning there is a need to conduct PAT tests regularly on such devices to maintain their safety.

Who is Responsible?

Under the Electricity at Work Act 1989, the responsibility of ensuring that equipment was safe – or, at least, scheduling tests with a competent expert – was that of the equipment owner; usually, this would be the company owners/directors or their direct representatives in the line manager or site manager.

If there is a maintenance manager present, the title of Duty Holder falls on them to organise regular PAT testing.

Is PAT Testing a Legal Obligation?

There is currently no direct law that stipulates or recommends a business owner conducts PAT testing; however, The Health and Safety at Work Act 1974 suggests that employers have a “duty to ensure the safety” of those using the work premises.

PAT testing has proven to be a quick, efficient and reliable method of adhering to the obligations placed on employers in the Acts of 1974 and 1989.

Understanding the Classifications

Before we go into depth with the PAT classes, we must first establish some background knowledge as to the purpose of the system.

A class of an appliance helps in determining if it requires a PAT test and the level of degree to which it should be tested.

When testing, a Class 1 appliance will require a full PAT test (as they are the most dangerous class), whilst Class 2 devices need a PAT insulation test.

On the other hand, Class 3 appliances do not need to be PAT tested, though testing of their charging leads and cables may be required.

The PAT Appliance Classes – Defined

Class 1 PAT Test

Class 1

These electrical appliances only have simple insulation and instead, rely on earth for protection. Such devices are the most common.

Class 2 PAT Symbol

Class 2

These electronic devices are outfitted with supplementary insulation and therefore have no reliance on earth for protection. Such devices will be identifiable with a double insulated marking (a square within a square): usually found on the manufacturer’s plate.

Class 3 PAT Symbol

Class 3

Low voltage electricals: they are the safest of the classes. They do not require a PAT test; however, the charging lead and cables may do. Class 3 devices will often carry a symbol that contains three vertical stripes within a diamond.

The Importance of Each PAT Class

The PAT classes, as well as the appliance category, are important because they are used collectively to determine what type of PAT testing is required and how regularly such tests should be carried out.

As devices and components that carry electric current are often delicate, the possibility of faulty occurrences remains very real: notably, if routine inspections are not occurring.

An honest and thorough examination of such equipment ensures that they are safe to use and pose no immediate threat to life or property. The legal obligation to keep workers and the public safe from harm means that although PAT testing is not a regulated requirement, it is at the very least a moral duty towards the safety of others.

Who Can PAT Test?

Under the HSE legislation, those who test electrical equipment must be competent and have the following credentials before conducting any PAT testing:

  • Experienced in electrical works.
  • Understand the system that they will work on.
  • Recognise and fix emerging problems or suggest solutions.
  • Competent understanding of hazards which may arise without adequate precautions.
  • Possess fundamental knowledge and education of electricity.

What Businesses Need PAT Testing?

In simple terms: any business which has electrical appliances intended for commercial purposes or function should maintain and test said electrical appliances.

Under HSE, business owners and management must maintain and ensure safety for workers, guests and customers.

It is also advisable for commercial persons who lend property and accommodation – hotel and motel owners, landlords etc. – to consider PAT testing to ensure the safety of guests and tenants: at least annually.

Our PAT Testing Services

Established to simplify fire safety compliance for businesses, Cardinal Fire Protection assists organisations that have fallen short in their approach to adequate fire safety.

Our aim is to assist your commercial day-to-day operations and obligations by providing direct and succinct fire safety advice and services, including regular PAT Testing.


Did you find our guide on the basics of PAT testing classes useful? If so, expand your knowledge with some information on what to do in case of a PAT test fail, how to conduct employee fire safety training and our comprehensive guide on BS5839.