PAT Testing Guide UK — Requirements, Law, and Best Practice 2026

PAT stands for Portable Appliance Testing. It is the process of checking electrical appliances and equipment to ensure they are safe to use. Despite the name, PAT testing covers more than just "portable" equipment — it includes any electrical equipment that has a plug and is connected to a mains supply, from kettles and laptops to photocopiers and vending machines.

The testing process involves two stages: a visual inspection (checking for damage to the cable, plug, and appliance casing) and, where appropriate, electrical testing using a PAT tester. The electrical tests typically include earth continuity (for Class I appliances), insulation resistance, and sometimes a functional check and earth leakage test.

PAT testing is carried out on in-service equipment — that is, equipment already in use, not brand-new items straight from the manufacturer. New equipment is assumed to meet safety standards when it leaves the factory (provided it carries a CE or UKCA mark), so it does not need PAT testing before first use, although it should be visually inspected before being put into service.

This is the part that causes the most confusion. There is no specific piece of UK legislation that says "you must PAT test your appliances." The phrase "PAT testing" does not appear in any Act of Parliament or statutory regulation. However, several pieces of legislation create a legal duty to ensure electrical equipment is safe:

• Electricity at Work Regulations 1989 (EAWR) — Regulation 4(2) states: "As may be necessary to prevent danger, all systems shall be maintained so as to prevent, so far as is reasonably practicable, such danger." This applies to all workplaces and is enforced by the Health and Safety Executive (HSE). The HSE considers PAT testing to be one way of demonstrating compliance with Regulation 4(2).
• Health and Safety at Work etc. Act 1974 — Section 2 places a general duty on employers to ensure, so far as is reasonably practicable, the health and safety of their employees. Section 3 extends this duty to non-employees (visitors, customers, contractors). Faulty electrical equipment that injures someone would be a breach of these duties.
• Provision and Use of Work Equipment Regulations 1998 (PUWER) — Regulation 5 requires that work equipment is maintained in an efficient state, in efficient working order, and in good repair. Regulation 6 requires that equipment is inspected where there is a significant risk from deterioration.
• Management of Health and Safety at Work Regulations 1999 — Regulation 3 requires employers to carry out a suitable and sufficient assessment of risks, including risks from electrical equipment.

The practical effect of all this legislation is clear: while PAT testing is not explicitly mandated, it is the recognised industry method for demonstrating that you have maintained electrical equipment in a safe condition. If an appliance causes an injury and you cannot show evidence of regular inspection and testing, you will struggle to defend a prosecution or civil claim.

The definitive reference for PAT testing in the UK is the IET Code of Practice for In-Service Inspection and Testing of Electrical Equipment. The current edition is the 5th Edition, published in 2020. This replaced the earlier 4th Edition and incorporated significant changes to testing frequency guidance and risk assessment methodology.

The IET Code of Practice is not a legal document — it is a guidance document published by the Institution of Engineering and Technology. However, it is recognised by the HSE, insurance companies, and the courts as the industry standard. Following the IET Code of Practice is the best way to demonstrate that your PAT testing regime is reasonable and proportionate.

Key principles from the 5th Edition:

• Risk-based approach — testing frequency should be determined by a risk assessment, not by a blanket annual schedule. Low-risk equipment in a low-risk environment (e.g., a desk lamp in an office) needs less frequent testing than high-risk equipment in a harsh environment (e.g., a power tool on a construction site).
• User checks are the first line of defence — the Code emphasises that regular user checks (visual inspection by the person using the equipment before each use) are more effective at preventing accidents than periodic formal testing alone.
• Visual inspection catches most faults — studies show that approximately 95% of faults on portable appliances can be detected by a thorough visual inspection without any electrical testing. Formal electrical testing is still necessary for certain equipment types and environments, but it complements visual inspection rather than replacing it.

PAT testing is relevant to anyone who has a duty to maintain electrical equipment in a safe condition. This includes:

• All employers — regardless of business size. A sole trader with one employee has the same legal duty as a multinational corporation. The scope and frequency of testing will differ, but the obligation exists.
• Landlords (especially HMOs) — landlords of Houses in Multiple Occupation (HMOs) are legally required to ensure that electrical appliances they supply (cookers, fridges, washing machines) are safe. While PAT testing is not specifically mandated for landlords, it is the accepted way to demonstrate compliance. Many local authorities require PAT test records as part of HMO licensing conditions.
• Public venues — hotels, pubs, restaurants, theatres, sports centres, and other venues open to the public have a duty of care to visitors. Insurance companies increasingly require evidence of PAT testing as a condition of public liability cover.
• Schools and nurseries — local authority and academy schools are required to have PAT testing programmes as part of their health and safety management systems.
• Construction sites — the CDM Regulations 2015 and the EAWR require that portable tools and equipment on construction sites are maintained and tested. 110V equipment should be tested every 3 months, with visual inspection before each use.
• Churches and community halls — any organisation that invites the public onto its premises has a duty of care, and insurance companies routinely require PAT testing records.

The IET Code of Practice 5th Edition provides suggested initial frequencies for formal inspection and testing. These are starting points — the actual frequency should be adjusted based on the results of previous inspections, the type and condition of equipment, and the environment in which it is used.

These frequencies are guidance, not law. The key principle is that testing must be frequent enough to ensure equipment remains safe between tests. Equipment that is subjected to heavy use, harsh conditions, or frequent damage will need more frequent testing. Equipment that is stationary, lightly used, and in a clean environment will need less frequent testing.

Understanding the difference between Class I and Class II appliances is fundamental to PAT testing because the tests you carry out differ between the two classes.

Class I Appliances

Class I appliances rely on a combination of basic insulation and an earth connection for safety. They have a metal casing (or accessible metal parts) that is connected to earth via the earth conductor in the mains cable. If the basic insulation fails and a live conductor touches the metal casing, the fault current flows to earth through the earth conductor, tripping the protective device (fuse or MCB) and disconnecting the supply before a user can receive a dangerous electric shock.

Examples: kettles with metal bodies, toasters, washing machines, dishwashers, electric ovens, desktop computers (metal chassis), angle grinders, and most power tools with metal casings.

PAT tests for Class I: earth continuity test (must be less than 0.1 ohm + cable resistance), insulation resistance test (must be at least 1 megohm at 500V DC), and functional check.

Class II Appliances

Class II appliances (also called double-insulated) rely on two layers of insulation for safety — basic insulation plus supplementary insulation. They do not have an earth connection and are identified by the double-square symbol on the rating plate. If the basic insulation fails, the supplementary insulation prevents the user from receiving a shock.

Examples: phone chargers, laptop power supplies, most plastic-cased power tools, hair dryers, televisions, desk lamps, and electric toothbrush chargers.

PAT tests for Class II: insulation resistance test (must be at least 2 megohms at 500V DC) and functional check. No earth continuity test is required because there is no earth connection.

The IET Code of Practice distinguishes between three levels of inspection:

User Checks

A simple visual check carried out by the person using the equipment before each use. No training is required — just common sense. Check the cable for cuts, fraying, or kinks. Check the plug for cracks or damage. Check the appliance casing for damage. Check that the equipment works normally. If any damage is found, stop using the equipment and report it.

Formal Visual Inspection

A more thorough visual inspection carried out by a competent person. This involves opening the plug to check the internal connections (correct wiring, correct fuse rating, cable grip secure, no damaged insulation inside the plug), checking the cable entry point to the appliance for strain or damage, checking for signs of overheating (discolouration, melted plastic), and checking that the rating plate is legible and appropriate for the supply. No electrical test equipment is required.

Combined Inspection and Test

A full formal visual inspection plus electrical testing using a PAT tester. This is the most thorough level of inspection and is what most people mean when they say "PAT testing." It includes all the visual checks above plus earth continuity testing (for Class I), insulation resistance testing, and where appropriate, earth leakage testing and functional checks. This level of inspection must be carried out by a competent person who has been trained in the use of the test equipment and understands the significance of the results.

The IET Code of Practice sets out clear pass/fail criteria for each electrical test:

• Earth continuity (Class I) — the resistance of the earth conductor from the earth pin of the plug to the accessible metal parts of the appliance should be less than approximately 0.1 ohm plus the resistance of the supply cable. For most appliances with cables up to 5 metres, a reading below 0.5 ohm is acceptable. Readings above 1 ohm indicate a problem with the earth connection.
• Insulation resistance (Class I) — must be at least 1 megohm (1 million ohms) at 500V DC between the live and neutral conductors connected together and the earth conductor. Readings below 1 megohm indicate deterioration of the insulation.
• Insulation resistance (Class II) — must be at least 2 megohms at 500V DC between the live and neutral conductors connected together and a metal foil wrapped around the appliance casing (to simulate contact with accessible surfaces).
• Earth leakage — protective conductor current should not exceed 3.5mA for Class I portable appliances or 0.75mA for Class II appliances. Higher earth leakage indicates insulation deterioration or a developing fault.

An appliance that fails any test must be taken out of service immediately, labelled as failed, and either repaired or disposed of. Failed appliances must never be returned to service without retesting and confirmation that the fault has been rectified.

Keeping accurate records of PAT testing is essential for two reasons: demonstrating compliance with the Electricity at Work Regulations to an HSE inspector or insurance company, and tracking the condition of equipment over time so you can adjust testing frequencies based on actual fault rates.

Records should include:

• A unique asset identifier for each appliance
• Description and location of the appliance
• Date of inspection and test
• Results of all visual checks and electrical tests
• Pass or fail outcome
• Name of the person carrying out the test
• Date of the next scheduled inspection
• Any remedial action taken for failed items

The traditional approach is to stick a pass/fail label on each appliance and maintain a paper register. Digital record keeping is more efficient and provides a better audit trail. With a digital system, you can search records instantly, generate reports for clients, track failure rates by equipment type, and schedule retests automatically.

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PAT Testing Certificates — Digital Records and Professional

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PAT testing is an excellent additional revenue stream for electricians. The barriers to entry are low (a basic PAT tester costs £200-£500 and training courses take 1 day), the work is straightforward, and demand is consistent because businesses need testing carried out at regular intervals.

Pricing PAT Testing

PAT testing is typically priced per appliance, with discounts for larger quantities. Typical rates in 2026:

• 1-50 appliances: £2.50-£3.50 per item
• 50-200 appliances: £1.50-£2.50 per item
• 200+ appliances: £1.00-£1.80 per item
• Minimum charge: £50-£80 per visit

A competent PAT tester can test 20-40 appliances per hour depending on the type of equipment and environment. An office with mostly IT equipment (monitors, PCs, printers) is faster to test than a workshop with a mix of portable power tools, extension leads, and industrial equipment.

Building a PAT Testing Round

The real value in PAT testing is building a regular round of recurring customers. A school that needs 300 appliances tested annually is worth £400-£700 per year. Ten schools in your area represent £4,000-£7,000 of recurring annual revenue for approximately 10 days of work. Add offices, pubs, hotels, churches, and letting agents, and PAT testing can easily contribute £10,000-£20,000 per year to your business.

Managing a PAT testing round requires good customer management — tracking when each client is due for retesting, scheduling visits efficiently to minimise travel, and sending reminders when testing is due.

In the app

Manage Your PAT Testing Business With Elec-Mate

Customer management, quoting, invoicing, expense tracking, and professional PAT certificates — everything you need to run a profitable PAT testing round.

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Elec-Mate's business tools are built for electricians running multiple service lines. The quoting app lets you generate PAT testing quotes with per-appliance pricing, the invoice builder sends professional invoices from site, and the customer management system tracks your entire client base with testing due dates and contact history. For pricing your PAT testing services, see our guide on how to price electrical jobs.