Contractors and members of the public sometimes ask how often an electrical installation should be subjected to periodic inspection and testing. This article considers the factors that inﬂuence the decision as to when the ﬁrst and subsequent periodic inspections should be carried out.
First periodic inspection
Every electrical installation deteriorates to some extent throughout its life and because of this Regulation 135.1 of BS 7671 recommends that every electrical installation be subjected to periodic inspection and testing, in accordance with Chapter 62. The rate at which a particular installation deteriorates usually depends on factors such as:
- a) the severity of the external inﬂuences that will affect the installation,
- b) the nature of the activities to be performed in the areas served by the installation, and
- c) the degree of wear, tear and damage likely to occur in normal use.
A recommendation for the interval to the ﬁrst periodic inspection should be provided by the electrical installation designer, and recorded on the Electrical Installation Certiﬁcate (Regulation 134.2.2) In making the recommendation, the designer should, together with the factors listed earlier, also take into account the frequency and quality of maintenance the installation can reasonably be expected to receive during its intended life (Regulation 341.1 refers). Additionally, consideration should also be given to any licensing conditions and statutory requirements regarding frequency of inspections that may be applicable to the installation.
Subsequent periodic inspections
The interval that was recommended to the ﬁrst periodic inspection might not be appropriate for subsequent inspections. For example, in making the recommendation for the interval to the ﬁrst inspection the designer may have made assumptions that have turned out to be inaccurate, or are no longer valid, about matters such as:
- the intended usage of the installation (such as loading, and frequency of use of equipment),
- the effects of external inﬂuences (such as temperature, wetness, dust or other foreign bodies, corrosive substances, impact or vibration), and
- the extent and effectiveness of ongoing maintenance.
As indicated by Regulation 622.1, matters such as those listed, as well as the ﬁndings and recommendations of the previous periodic inspection, if any, should be taken into account when deciding on the period to the next inspection.
Electrical installations open to the public may be subject to licensing conditions which dictate the frequency of inspection and testing. For a cinema an interval of between one and three years would be typical, whereas a petrol ﬁlling station or a caravan park will generally be required to be subjected to inspection and testing annually.
As shown in Table 1, some of the special installations or locations contained in Part 7 of BS 7671, state the recommended frequency for inspection and testing.
Regular inspections of a particular frequency might be a requirement of a British Standard or a Code of Practice, such as is the case with some aspects of ﬁre detection and ﬁre alarms systems and emergency lighting installations.
It should be noted that those recommendations appearing in guidance taken from statutory instruments, British Standards or Codes of Practices could be subject to change as and when those documents are revised. It is the responsibility of the designer of the installation to be aware of, and to act on, the most up to date information and requirements at all times.
Regulation 4(2) of the Electricity at Work Regulations 1989 (EWR) places an obligation on duty holders to maintain electrical systems (as deﬁned in those regulations), so far as is reasonably practicable, in order to prevent danger. This maintenance requirement applies to all places of work.
For rented accommodation, the Landlord and Tenant Act 1985 (England and Wales) and the Housing (Scotland) Act 2006 places obligations for the suitability of the condition of the electrical installation to be assured at the start of and throughout the period of any tenancy.
Very speciﬁc requirements are laid down in The Management of Houses in Multiple Occupation (England) Regulations 2006 with respect to properties falling within their scope. Regulation 6 (3) requires, that every ﬁxed electrical installation is inspected and tested at intervals not exceeding ﬁve years by a person qualiﬁed to undertake such inspection and testing.
The Certsure publication Inspection, testing and certiﬁcation provides guidance on the initial frequency of periodic inspections for installations in a wide range of typical premises. Whilst the periods given provide a useful starting point, they should not be seen as a substitute for a proper assessment of the interval required between periodic inspections, particularly where the installation or premises are not typical.
The Inspection, Testing and Certiﬁcation book, along with many other NICEIC and ELECSA titles will soon undergo updating to the 18th Edition of BS 7671, which is due to be published later this year.