Electrical Testing Intervals

Electrical Testing Intervals for all types of Premises.

We are often asked how often particular properties need to be tested, it can be unclear for customers and clients alike.
Below is a concise breakdown of what you need to know for your particular type of property.

Testing Intervals

The frequency of periodic inspection and testing must be determined taking into account:
  • The type of installation
  • Its use and operation
  • The frequency and quality of maintenance
  • The external influences to which it is subjected
  The table below provides guidance on the frequency of formal inspections of electrical installations as well as routine checks.


  1. Particular attention must be taken to comply with S1 2002 No 2665 – Electricity Safety, Quality and Continuity Regulations 2002 (as amended).
  2. Electricity at Work Regulations 1989, Regulation 4 and Memorandum of guidance (HSR25) published by the HSE.
  3. BS 5266-1:2011 Emergency lighting. Code of practice for the emergency escape lighting of premises
  4. Other intervals are recommended for testing operation of batteries and generators.
  5. BS 5839-1:2013 Fire detection and fire alarm systems for buildings. Code of practice for design, installation, commissioning and maintenance of systems non-domestic premises
  6. Local Authority Conditions of Licence.
  7. It is recommended that a caravan is inspected and tested every three years, reduced to every year if it is used frequently (see
  8. Regulation 721.514.1 and Fig 721 – Instructions for electricity supply).
  9. The person carrying out subsequent inspections may recommend that the interval between future inspections be increased or decreased as a result of the findings of their inspection.
  10. Medical locations shall have their isolating transformer equipment inspected and tested for functionality as well as alarms etc.; every third year the output leakage current of the IT isolating equipment shall be measured.
  11. The Landlord & Tenant Act 1985 requires that properties under the Act have their services maintained. Periodic inspection and testing is the IET recognised method of demonstrating this.
  12. The Management of Houses in Multiple Occupation (England) Regulations and the Management of Houses in Multiple Occupation (Wales) Regulations.