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IET Code of Practice for PAT Testing

Introduction to IET Code of Practice for PAT Testing

Portable Appliance Testing (PAT) is a critical process in maintaining the safety and functionality of electrical equipment within various environments. It involves routine inspection and testing of electrical appliances to ensure they are safe to use. The IET Code of Practice provides comprehensive guidelines for the in-service inspection and testing of electrical equipment, ensuring compliance with safety regulations and standards.

Overview of the IET Code of Practice

The IET (Institution of Engineering and Technology) Code of Practice for In-Service Inspection and Testing of Electrical Equipment, currently in its 5th Edition, is the definitive guide for PAT testing in the UK. This document outlines the essential procedures, standards, and requirements for effectively managing the safety of electrical equipment. It emphasizes a risk-based approach, ensuring that inspection and testing frequencies are tailored to the specific risks associated with different environments and types of equipment.

Key Changes in the 5th Edition

The 5th Edition of the IET Code of Practice has introduced several significant changes to reflect modern equipment and practices. Here are some of the critical updates:

Emphasis on Risk-Based Assessment

The latest edition places a greater emphasis on conducting risk assessments to determine the frequency of inspections and tests. This approach replaces the previous reliance on a fixed table of suggested frequencies, encouraging duty-holders to evaluate the specific conditions and risks of their environments and equipment​.

Updated Test Procedures and Limits

Several test procedures and limits have been updated to align with advancements in technology and better practices. For example, the leakage test limit has been increased to 5 mA for both Class I and Class II equipment. This change acknowledges the difficulties in obtaining accurate readings with the previous lower limits, especially for certain appliance types like washing machines and microwave ovens​.


Removal of Specific Terminology

The 5th Edition has removed terms such as "portable" and "appliance" from the main text, reflecting a broader focus on all types of electrical equipment, whether or not they are portable. This shift ensures that equipment such as air-conditioning units and security access control systems, which may be wired into the installation, are included under the guidance of the Code.

New Equipment Classifications

The introduction of new equipment classifications, such as Class II FE (Functional Earth), provides clearer guidance on how to handle different types of equipment. This classification is particularly relevant for IT and communication devices that require an earth connection for functional purposes rather than for safety.

Enhanced Appendices and Guidance

The appendices have been significantly expanded to include guidance on low-risk equipment, example risk assessments, and a basic electrical theory primer. This additional material supports duty-holders in understanding the practical aspects of PAT testing and ensuring compliance with the Code​.

Implementing the IET Code of Practice in Your PAT Testing Regime

Conducting a Risk Assessment

The first step in implementing the IET Code of Practice is to conduct a thorough risk assessment of your electrical equipment. Consider factors such as the environment in which the equipment is used, the equipment’s frequency of use, and the skill level of the users. This assessment will help you determine the appropriate frequency and extent of inspections and tests​.

Performing Visual Inspections

Regular visual inspections are crucial for identifying potential hazards, such as damaged cables, exposed wires, or signs of overheating. The Code provides detailed guidance on what to look for during these inspections, ensuring that even minor issues are promptly addressed before they escalate into significant safety risks.

Electrical Testing

In addition to visual inspections, electrical testing is essential for verifying the safety and functionality of equipment. The 5th Edition of the Code outlines specific tests to be performed, including earth continuity tests, insulation resistance tests, and leakage current tests. Ensure that your PAT testers are equipped with the latest testing instruments that comply with the updated limits and procedures.​ 

Documentation and Record Keeping

Maintaining accurate records of all inspections and tests is a critical aspect of PAT testing. Document the results of each test, including any faults identified and the corrective actions taken. This documentation not only ensures compliance with legal requirements but also helps in tracking the performance and safety of your equipment over time​.


The IET Code of Practice for PAT Testing is an indispensable resource for anyone responsible for the safety of electrical equipment in the UK. By following the guidelines and implementing a risk-based approach to inspections and testing, you can ensure that your electrical equipment remains safe and functional, protecting both your employees and your business.

For more detailed information, you can refer to the official IET Shop where you can purchase the latest edition of the Code of Practice. Additionally, the Portable Appliance Testing Trade Association (PATTA) provides valuable insights and updates related to PAT testing practices and standards.

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