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The 4th edition of the IET Code of practice

August 29, 2014 featured image

The 4th edition of the IET Code of Practice (CoP) focuses on the importance of risk assessment based on an electrical appliance’s type, environment and usage. A proportionate response to testing and inspection is essential to ensure all workplace electrical systems are maintained and safe.

New guidance

To help those responsible assess this risk, the latest IET CoP has been expanded to include more electrical equipment categories and workplaces, alongside detailed explanatory notes and definitions of inspection and testing methods. The main thrust of the new edition highlights the importance of taking a structured approach to risk assessment, with the frequency that equipment is inspected and tested reviewed after every inspection.

The 4th edition also reiterates that risk assessments are the responsibility of the duty holder (facilities managers, building managers, landlords or other such responsible people), but that a duty holder may enlist the services of a competent person to assist in this process.

‘Risk’ is recognised as encompassing many factors which will influence decisions on electrical inspection and test frequencies. As a guideline, the IET CoP highlights the main considerations to enable an informed decision:

  • The environment: equipment installed in a benign environment, such as an office, will suffer less damage than equipment in an arduous environment; a construction site, for example.
  • The users: if users of equipment report damage as soon as it becomes evident, hazards will be avoided. Conversely, if equipment is likely to receive unreported abuse, more frequent inspection and testing may be needed.
  • The equipment construction: the safety of a Class I appliance is dependent upon a connection with the earth of the fixed electrical installation. If the flexible cable is damaged, the connection with earth can be lost.

The safety of a Class II appliance is not dependent upon the integrity of the electrical installation. If Class II equipment is used in a low risk environment, such as an office, recorded inspection only may be sufficient.


  • The equipment type: a handheld appliance is more likely to be damaged than a fixed appliance. If a hand held appliance is also Class I, the risk of danger is increased – safety is dependent upon the continuity of the protective conductor from the plug to the appliance.
  • The frequency of use: how often an appliance is used is important; particularly where portable, movable and handheld appliances are concerned. Frequent use may decrease service life and increase exposure to possible damage.
  • Type of installation methods: installation methods should be taken into account, especially when assessing fixed equipment. The isolator position and cable management can be important factors when assessing risk.
  • Previous records: where previous records of inspection, testing and maintenance are available, these should be used to evaluate the frequency of subsequent inspections and tests. They will provide a history of the environment, the users and how this affects the condition of the appliances within it.

(Source: Code of Practice for In-service Inspection and Testing of Electrical Equipment (4th Edition), IET, 2012)

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