BS7671 is a little vague on this subject.
In 7671 it merely states that the time shall be determined taking into account maintenance blah blah.
OR, that where the installation is effectively managed by competent persons with preventative maintenance undertaken with records kept etc. then PIR is not required.
The frequency to the first required I&T - Periodic Inspection Report (PIR) is determined by the competent person undertaking the initial inspection and test when the equipment is installed, that is specified on the Electrical Installation Certificate (EIC).
Now IET guidance note 3 on which the City & Guilds course in inspection & testing of electrical installations is based, known as 2391-10 (not the -20 course as this is a much more basic version) has a lot more to say.
I can’t copy the table from the book or post an attachment as far as I know and the table is too big to get into a post.
The timescale depends on the type of property basically.
Domestic, PIR due on change of occupancy or every 10 years
Every 3 months – construction sites
Every year – cinema (though can be up to 3), caravan parks, marinas, fish farms, swimming pools, fire alarms, laundrettes, petrol filling stations
Every 3 years – Industrial leisure complex (excl. swimming pools), places of public entertainment, theatres, agricultural & horticultural, caravans, emergency lighting
Every 5 years – commercial, educational establishments, hospitals, residential accommodation, offices, shops, laboratories, church installations, restaurants & hotels, public houses, village halls, community centres.
Every 6 years – highway power supplies
Every 10 years – domestic
Domestic & commercial should also be done at change of occupancy
In between these then a routine check should be undertaken.
Daily/monthly – emergency lighting
Daily/weekly/monthly – fire alarms
Every 4 months – educational establishments, marinas, fish farms, swimming pools
Every 6 months – caravan parks
Every year – commercial, hospitals, industrial, offices, shops, laboratories, cinemas, church installations, leisure complex (excl. swimming pools), places of public entertainment, restaurants & hotels, theatres, public houses, village halls, community centres, agricultural & horticultural, caravans, laundrettes residential accommodation (also at change of occupancy).
There are also notes to the table with regard to other standards, guidance and that licensing conditions may well modify these timescales.
GN3 is in itself 118 pages, and is one of a series of 8 as well as BS7671 & several other specialist books issued by the IEE relating to the interpretation implementation of BS7671.
HTH