The technical experts at NICEIC have created this guide to the appropriate use Minor Works Certificates.
Where an addition or alteration is made to an existing ﬁnal circuit, as shown in Fig 1, it should be veriﬁed that the work complies with BS 7671 and does not impair the safety of the existing installation (Regulation 610.4 refers). Whilst for such purposes a minor works certiﬁcate may be used as an alternative to an Electrical Installation Certiﬁcate (EIC), Regulation 631.3 requires that a separate minor works certiﬁcate is issued for each circuit worked on.
A minor works certiﬁcate must not be used to certify the installation of a new circuit, even if the circuit supplies only one point (one accessory). It should be noted that before an addition or alteration is undertaken, Regulation 132.16 requires the adequacy of the existing installation to be assessed, including the earthing, bonding and maximum demand, for the altered circumstances.
Replacement of a single protective device
A minor works certiﬁcate may be issued to certify a ‘like-for-like’ 1 replacement of a single protective device or a single item of switchgear containing a single protective device.
In addition, a minor works certiﬁcate may also be issued for the replacement of a device that is not considered ‘like-for-like’, but only in circumstances where the skilled person undertaking the replacement can verify that the replacement device satisﬁes the requirements of BS 7671, particularly, for the safe disconnection of the circuit under overload and fault conditions.
For example, where an observation on an Electrical Installation Condition Report identiﬁes that the measured earth fault loop impedance for an existing Type C circuit-breaker exceeds the maximum value permitted by BS 7671, the remedial work required may involve replacing the existing circuit-breaker with an RCBO, or replacing the Type C circuit-breaker with a Type B circuit-breaker, or if possible, de-rating the device (for example replacing a 10A protective device with a 6A device).
For any of the options previously described, the minor works certiﬁcate may be used as it makes provision for the skilled person undertaking the work to record the relevant inspections and tests, as shown in Fig 2, required to verify that the work complies with BS 7671 and does not impair the safety of the existing installation.
Replacement of switchgear incorporating more than one protective device
The replacement of an item of switchgear which incorporates more than one protective device, such as a two-way (or more) consumer unit, is not minor work. Such work requires a greater degree of inspection and testing, including where relevant parts of the existing installation, than would be required for work carried out on an existing single circuit.
For these reasons, the Notes For Recipient, printed on the reverse of NICEIC and ELECSA minor works certiﬁcates (which are based on the notes contained in Appendix 6 of BS 7671) state that the certiﬁcate is not suitable for certifying the replacement of a consumer unit (or distribution board), for which an appropriate EIC should be used.
Guidance on completing Certiﬁcates and Reports is given in the NICEIC and ELECSA publication: Inspection, Testing and Certiﬁcation.
Replacement of an RCD
Where an existing RCD needs to be replaced, for example, because of a failure of the test button, the replacement may be certiﬁed using a minor works certiﬁcate, but the requirements of Regulation 132.16 should be satisﬁed before the work is undertaken. For example, prior to the replacement of an RCD that is used for the purposes of providing fault protection for the ﬁnal circuit(s) of an installation connected to a TT supply system, as shown in Fig 3, the condition and adequacy of the earth electrode, earthing conductor and protective bonding conductors should be veriﬁed as a minimum.
Replacement of an accessory
While the minor works certiﬁcate may be used to certify the replacement of an accessory, for example, a socket-outlet or a light ﬁtting on a ‘like-for-like’ basis, such work generally falls under the category of maintenance work and so the client, such as a local authority, can choose to use their own documentation instead. However, where this is the case, the safety declaration, installation details, and the inspection and test results recorded on the client’s documentation should be no less comprehensive than that which would have been required on the minor works certiﬁcate, and a copy of the completed documentation should be retained by the contractor. Where a minor works certiﬁcate is used to certify the replacement of accessories, a separate certiﬁcate is required for each circuit aﬀected. Therefore, a single certiﬁcate may be used to certify the replacement of more than one accessory connected to the same circuit, but should not be used to certify modiﬁcations carried out on diﬀerent circuits.
Replacing protective bonding conductors
The installation or upgrading of main or supplementary protective bonding can be recorded on a minor works certiﬁcate, however, where protective bonding is carried out in more than one location, such as an outbuilding or garage detached from the main installation, a separate minor works certiﬁcate should be issued for each location.