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. (Table extracted from BS7671 IET Wiring Regulations 17th Edition).

Type of Installation Routine check Maximum period between
inspections and testing
as necessary
General installation
Domestic accommodation -
Domestic accmomdation -
rented houses and flats

change of occupancy/10 years
change of occupancy/5 years

Commercial 1 year change of occupancy/5 years
Educational establishments 6 months 5 years
Hospitals and medical clinics -
general areas
Hospitals and medical clinics -
medical locations
1 year

6 months
5 years

1 year

Industrial 1 year 3 years
Residential accommodation (Houses of
Multiple Occupation) - halls of residence,
nurses accommodation, etc.
1 year Change of occupancy/5 years
Offices 1 year 5 years
Shops 1 year 5 years
Laboratories 1 year 5 years
Buildings open to the public
Cinemas 1 year 1-3 years
Church installations 1 year 5 years
Leisure complexes
(excluding swimming pools)
1 year 3 years
Places of public entertainment 1 year 3 years
Restaurants and hotels 1 year 5 years
Theatres 1 year 3 years
Public houses 1 year 5 years
Village halls/Community centres 1 year 5 years
Special and specific installations
(for medical locations see above)
Agricultural and horticultural 1 year 3 years
Swimming pools 4 months 1 year
Caravan parks
1 year
6 months
3 years
1 year

Highway power supplies as convenient 6-8 years
Marinas 4 months 1 year
Fish farms 4 months 1 year
Emergency lighting daily/monthly 3 years
Fire alarms daily/weekly 1 year
Launderettes monthly 1 year
Petrol filling stations 1 year 1 year
Construction site installations 3 months 3 months

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