NAPIT’s Bill Allan explains how the Minor Works Certificate should be used.
It is a fundamental principle of BS 7671that every electrical installation must be provided with appropriate documentation (Regulation 132.13) but since the Minor Electrical Installation Works Certificate (commonly called the Minor Works Certificate and often abbreviated to MWC) was introduced in 1993, there has been some confusion over its use. This confusion is particularly prevalent among those who may be trained in other trades (e.g. plumbers, gas engineers, security etc.) but who regularly carry out minor electrical installation work as part of their duties, even though they are not considered as electrically skilled person(s). It is not uncommon for such people to fail to provide certification at all for minor works, causing one to wonder whether they carry out any inspection and testing at all. The lack of testing after the completion of electrical installation work, including minor electrical work, is a clear contravention of BS 7671 (see Regulations 134.2.1, 631.3 and 633.1) and is fraught with risk. The standards for safety are not reduced for minor works.
However, even among electricians, inappropriate use of the MWC is all too common.
This article will explain how the Minor Works Certificate should be used.
Appropriate inspection and testing must be carried out when undertaking minor electrical installation work and the results of the tests must be recorded but some confusion has possibly been caused by the use of the word, ‘may’ in Regulation 631.3. It states, ‘Where minor electrical installation work does not include the provision of a new circuit, a Minor Electrical Installation Works Certificate, based on the model in Appendix 6, may be provided for each circuit altered or extended as an alternative to the Electrical Installation Certificate’.
This Regulation is simply saying that, where minor works are carried out, the installer has a choice of providing either a full Electrical Installation Certificate or a MWC. There is no option to omit certification for electrical installation work.
What minor works are
The term, ‘Minor works’ is clearly defined in Part 2 Definitions of BS 7671 as, ‘Additions and alterations to an installation that do not extend to the provision of a new circuit’. A note to this definition states, ‘Examples include the addition of socket-outlets or lighting points to an existing circuit, the relocation of a light switch etc’.
This is repeated in the Notes to the MWCs in Appendix 6 of BS 7671.
One MWC, multiple jobs
On reading this, some installers think that it is necessary to complete one MWC for each individual item of minor work but that is not necessary in every case. If, for example, you add one socket-outlet or ten socket-outlets to one existing circuit, both are considered to be minor work and one single MWC would suffice in each case. Similarly, whether you add one lighting point or ten lighting points to one existing circuit, one single MWC would be adequate.
However, a separate MWC must be issued for each circuit altered or extended. Where say, five lighting points were added to one circuit and five lighting points were added to a different circuit, then two MWCs would be required.
Some are under the impression that like-for-like replacement of accessories is regarded as maintenance rather than installation work and that no certification is required.
As in Regulation 631.3, the word, ‘may’ in the third sentence of the Notes to the MWC in Appendix 6 of BS 7671 could be causing some confusion. It states, ‘This Certificate may also be used for the replacement of equipment such as accessories or luminaires, but not for the replacement of distribution boards or similar items’.
Where one accessory, such as a broken socket-outlet, is replaced, the same tests are required as if a socket-outlet had been added to the circuit or relocated. The final sentence in the Notes states, ”Appropriate inspection and testing, however, should always be carried out irrespective of the extent of the work undertaken’.
Appropriate inspection and testing is listed in the MWC, Part 3, Essential Tests. They are tests for earth continuity, insulation resistance, earth fault loop impedance, polarity and, if applicable, RCD operation.
Existing Installation, Circuit Details & Dangerous situations
The installation details including the system earthing, fault protection and protective device details must also be recorded.
Where a contractor discovers a dangerous or potentially dangerous situation in the existing installation, such as the absence of a connection to Earth, the work must not proceed. The client should be advised of the situation immediately, preferably in writing.
Comments on the existing parts of the installation should be detailed in the MWC. Any items that can have a detrimental effect on the work being carried out would have to be rectified before the minor works can commence.
Recording test results
Without the provision of a MWC with a record of the test results, after alterations or additions the electrical duty holder would not be able to confirm the that the electrical installation is safe in the event of any incident developing in the future.
In addition, ‘Guidance for recipients’ on page 418 of BS 7671, says in referring to the MWC, ‘If you later vacate the property, this Certificate will demonstrate to the new owner that the minor electrical installation work carried out complied with the requirements of British Standard 7671 at the time the Certificate was issued’.
The MWC is an appropriate form on which to record the test results but they could also be recorded on some alternative certification that was adapted to clearly record all the essential test results, as long as it was based on the model MWC in Appendix 6. There are a number of such variations of the MWC model form in use by leading bodies in the electrical industry.
In most circumstances, it only takes a few minutes to complete the required tests and a few more minutes to complete the MWC. Where one or more of the essential tests has not been carried out, the installer should clearly state the reason(s). The way in which a contractor completes an electrical certificate, including MWCs, says a great deal about the kind of contractor he or she is.