A Minor Electrical Installation Works Certificate (MEIWC) is the BS 7671 certificate for an addition or alteration to one existing circuit that does not create a new circuit. Regulation 644.4.201 requires a separate certificate for each circuit worked on, and the notes on the IET model form rule it out for replacing a consumer unit or distribution board, which always needs an Electrical Installation Certificate (EIC). The current model form is the BS 7671:2018+A4:2026 version dated 15 April 2026, laid out in Sections A to E, and from 15 October 2026 it is the form to use. It is short, but it is a full certificate: real test results for the altered circuit and confirmation that the earthing and bonding are adequate.
- Use an MEIWC for an addition or alteration to one existing circuit; never for a new circuit, however short, and never for a board change.
- One circuit, one certificate: Regulation 644.4.201. Scheme pads that print two or four circuit panels are several certificates on one sheet.
- Before you alter anything, Regulation 132.16 requires you to assess the existing installation, including earthing, bonding and maximum demand; Section B of the form is where that assessment is recorded.
- Record continuity, insulation resistance, polarity, Zs and the RCD disconnection time for the altered circuit, plus AFDD and SPD checks where fitted.
- Like-for-like replacement of accessories or a single protective device can go on an MEIWC; a two-way or larger consumer unit cannot (NICEIC).
- Part P notification in England applies to minor works only in special locations; Wales still notifies kitchen and outdoor work.
What is a Minor Electrical Installation Works Certificate?
Appendix 6 of BS 7671 gives three model forms: the Electrical Installation Certificate, the Minor Electrical Installation Works Certificate and the Electrical Installation Condition Report. The MEIWC exists because a multi-page EIC with full schedules is disproportionate every time a socket is added, but Chapter 64 still applies. Regulation 641.5 requires an addition or alteration to be verified as complying with BS 7671 and as not impairing the safety of the existing installation, and Regulation 644.4.201 lets that verification be certified on an MEIWC for work that does not extend to a new circuit, with a separate certificate for each circuit.
The scope line printed at the top of the IET form is the whole test in one sentence: "To be used only for minor electrical work which does not include the provision of a new circuit." One person signs, and by signing takes responsibility for design, construction, inspection and testing of the minor work.
The A4:2026 model form replaced the A2:2022 version (dated 28 March 2022) on 15 April 2026, and BS 7671:2018+A2:2022 was withdrawn on 15 October 2026. The content is close, but the layout moved from Parts 1 to 5 to Sections A to E, the earthing arrangement list grew, and the declaration now reads "BS 7671:2018 amended to" with a date for you to fill in. Our page on Amendment 4 certificates covers the transition.
When should I use a Minor Works Certificate instead of an EIC?
Ask two questions. Has the work created a new circuit? Has it replaced a consumer unit or distribution board? If the answer to both is no and the work is confined to one existing circuit, the MEIWC is the right form. If either answer is yes, you need an EIC. Our guide to the Electrical Installation Certificate covers that side.
| Job | Certificate | Why |
|---|---|---|
| Double socket added to an existing ring final | MEIWC | Addition to an existing circuit; record r1, rn, r2 as well as R1+R2 |
| New switch position and cable for a light fitting | MEIWC | Alteration to an existing lighting circuit |
| Cooker circuit extended to a new hob position | MEIWC | Alteration to an existing radial, provided cable and device remain adequate |
| Outdoor socket spurred from a ring, 30 mA RCD | MEIWC | Addition; RCD disconnection time must be recorded |
| Damaged cable section replaced like for like | MEIWC | Repair to an existing circuit |
| One MCB swapped for an RCBO of the same rating | MEIWC | Single protective device; verify disconnection under fault (NICEIC) |
| Main bonding to gas and water upgraded | MEIWC | Bonding work can be certified on an MEIWC; one certificate per location |
| New circuit for a shower, cooker or EV charger | EIC | New circuit, even from a spare way |
| Consumer unit replaced | EIC | Affects every circuit; full schedules required |
| Full or partial rewire | EIC | New circuits |
| Socket added and a new lighting circuit on the same visit | EIC, or MEIWC for the socket plus EIC for the new circuit | A new circuit is involved |
The borderline cases are worth a closer look.
Adding a socket
Confirm the circuit type and protective device. Regulation 411.3.3 requires 30 mA RCD additional protection for socket-outlets rated up to 32 A; since A2:2022 the only permitted exception is for installations other than dwellings, with a documented risk assessment, and the A4 form has a box for exactly that under "permitted exceptions (Regulation 411.3.3)". If the existing circuit has no RCD, adding the socket on it without providing RCD protection is a departure you would have to justify, not a comment to note and walk away from. On a ring, record the end-to-end r1, rn and r2 figures as well as R1+R2 at the new outlet; see our ring final circuit testing guide.
Replacing or moving a light fitting
Swapping a fitting like for like is maintenance. Once you run new cable, add a switch drop or move the point, it is an alteration and an MEIWC is the right form. Regulation 411.3.4 requires 30 mA RCD protection for luminaire circuits in domestic (household) premises. If the lighting circuit you are extending has none, you either provide it (an RCBO swap for that way is itself minor work) or record the departure and the reasoning in Section A. Polarity matters more on lighting alterations than anywhere else; our polarity testing guide covers the switch-drop traps.
Extending a cooker circuit
Moving a cooker connection unit or running on to a new hob position is an alteration. Regulation 132.16 requires you to check that the existing cable and protective device stay adequate for the load and the extra length, so re-run the diversity and the volt drop; our cooker circuit guide has the numbers. If the cable or device has to change, the honest certificate is usually an EIC for what is in effect a new circuit.
Outdoor sockets and garden supplies
A socket spurred from a ring to the outside wall is minor work in England and not notifiable there. A supply to a shed, garage or outbuilding is a new circuit and an EIC, and in Wales any outdoor work is notifiable. Our garden and outdoor sockets guide and outbuilding supply guide cover both.
Like-for-like replacements
NICEIC's guidance, first published in February 2017 and still the reference, draws the lines clearly. A single protective device, or a single item of switchgear containing one, can be replaced and certified on an MEIWC, and so can a non-like-for-like replacement (a Type C breaker swapped for a Type B or an RCBO where Zs is too high) as long as you verify disconnection under overload and fault conditions. Replacing an RCD is fine on an MEIWC provided the Regulation 132.16 assessment is done first; on a TT system that means checking the electrode, earthing conductor and bonding as a minimum. Replacing switchgear with more than one protective device, meaning a two-way or larger consumer unit, is not minor work and needs an EIC. Several accessories replaced on the same circuit can share one MEIWC; accessories on different circuits cannot.
What does the A4:2026 Minor Works form ask for?
The IET model form dated 15 April 2026 runs to five lettered sections. Scheme pads follow the same structure with their own branding, and an assessor will expect every box dealt with.
| Section | Title | What goes in it |
|---|---|---|
| A | Description of the minor works | Client, date completed, address, plain description of the work, departures from BS 7671 (Regulations 120.3, 133.1.2, 133.1.3, 133.5), permitted exceptions (Regulation 411.3.3) and whether a risk assessment is attached, comments on the existing installation including defects observed (Regulation 644.1.2) |
| B | Presence and adequacy of earthing and bonding (Regulation 132.16) | System earthing arrangement: TN-S, TN-C-S (PME), TN-C-S (PNB), TT, TN-C or IT; earth fault loop impedance at the distribution board (Zdb); presence of adequate earthing conductor and main protective bonding to water, gas, oil, structural steel and other |
| C | Circuit details | DB reference, location and type; circuit number and description; reference method (Table 4A2); live and cpc csa; overcurrent device BS (EN), type, rating and breaking capacity; RCD BS (EN), type, rating, IΔn and rated time delay; AFDD BS (EN) and rating; SPD BS (EN) and type |
| D | Test results for the altered or extended circuit | R1+R2 or R2; r1, rn, r2 for a ring; insulation resistance test voltage, live-live and live-earth; polarity; maximum measured Zs; RCD disconnection time at IΔn and test button; AFDD test button; SPD functionality |
| E | Declaration | The work does not impair the safety of the existing installation and complies with BS 7671:2018 amended to [date] except as detailed in Section A; name, company, address, signature, position, date |
Three points on that layout catch people out. First, Section B asks for Zdb, the loop impedance at the board feeding the circuit, not Ze at the origin; if the board is the main consumer unit, Zdb and Ze are the same measurement, but on a sub-board they are not. Second, the earthing conductor and bonding boxes are a declaration that you looked and found them adequate, not that they exist: an undersized or missing gas bond is a defect for Section A and a job to quote for. Our main protective bonding glossary page gives the Table 54.8 sizes. Third, the comments box in Section A is the only place to record what you saw and did not fix, and it is what protects you when the EICR two years later finds the same plastic board or borrowed neutral.
What tests must be recorded on a Minor Works Certificate?
Section D is headed "where relevant and practicable", which means every test that applies to the circuit, not the ones that were convenient. For the altered circuit that is the full initial verification sequence of Chapter 64.
| Test | What to record | Pass criterion |
|---|---|---|
| Protective conductor continuity | R1+R2 in ohms, or R2 where R1+R2 is impracticable | Continuous cpc to the new point; the figure also feeds the Zs check |
| Ring final circuit continuity | r1, rn and r2 end to end | r1 and rn similar, r2 about 1.67 times r1 for 2.5/1.5 mm² cable; cross-connected readings consistent |
| Insulation resistance | Test voltage, live-live and live-earth in MΩ | Minimum 1.0 MΩ at 500 V d.c. for a 230 V circuit (Table 64); under 2 MΩ, investigate (IET GN3) |
| Polarity | Confirmed | Line to the switch and to the correct terminal at every point |
| Earth fault loop impedance | Maximum measured Zs at the furthest point | Below the Table 41 value for the device, usually with the 0.8 correction for a cold reading |
| RCD | Disconnection time in ms at IΔn, test button | 300 ms general type, 130 to 500 ms S-type; single test at IΔn under Regulation 643.8 |
| AFDD | Test button operation where one is fitted | Device trips |
| SPD | Functionality indicator | Indicator shows healthy; not all SPDs have one |
Three of those have their own guides on this site: insulation resistance testing, maximum Zs values and RCD testing. The point that matters here is that the MEIWC asks for the same numbers as the schedule of test results on an EIC, just for one circuit. Since Amendment 2 in 2022 the RCD test has been a single measurement at rated residual current, and the form has only the one box for it. If the RCD trips the whole board, you test it once and record the same figure on each certificate it protects.
Remember that the insulation resistance test is on the altered circuit, and the whole of that circuit, not just the new leg. Lift the circuit's neutral if the board is a shared-neutral-bar type, isolate anything electronic the circuit feeds, and test at 500 V. A low reading on the existing part of the circuit is a comment for Section A and a conversation with the customer, but it is still your reading on your certificate. Our low insulation resistance troubleshooting guide covers what to do when it happens.
How does Part P notification apply to minor works?
Part P of the Building Regulations applies in England and Wales and requires certain electrical work in dwellings to be notified to building control, either directly or through a competent person scheme such as NICEIC, NAPIT or Stroma. The lists differ between the two countries.
| England (since 6 April 2013) | Wales | |
|---|---|---|
| New circuit | Notifiable | Notifiable |
| Consumer unit replacement | Notifiable | Notifiable |
| Addition or alteration in a special location (bath or shower room zones, swimming pool, sauna heater) | Notifiable | Notifiable |
| Extending a circuit in a kitchen | Not notifiable | Notifiable |
| Outdoor socket, garden lighting, supply to an outbuilding | Not notifiable (the outbuilding supply is still a new circuit) | Notifiable |
| Addition or alteration elsewhere, repairs, like-for-like replacement | Not notifiable | Not notifiable |
So most minor works in England are not notifiable: a socket added in a lounge or on the outside wall still needs an MEIWC but no notification. A shaver socket, extractor fan or downlight within a bathroom zone is notifiable even though the certificate is still an MEIWC. The IET notes that the Welsh Building Regulations have diverged from England since 31 July 2014, and the Planning Portal confirms that in Wales "special locations include kitchens and outdoors" for this purpose. Scotland has no Part P; electrical work there sits under the Building (Scotland) Regulations and the building warrant system, but the certificate you issue is still the BS 7671 Appendix 6 form.
Keep the two documents separate in your head and in your explanation to the customer. The MEIWC is your evidence that the work complies with BS 7671. The Building Regulations compliance certificate from your scheme is the customer's evidence that the notifiable work was notified. One does not replace the other; see our Part P notification guide for the process and the fees.
What are the common misuses of the Minor Works Certificate?
Scheme assessors and EICR inspectors see the same errors repeatedly, and several of them turn up as observations on the next report.
Consumer unit changes. The most common misuse, and the one the model form itself prohibits in its notes. A board change is an EIC with a schedule of inspections and a full schedule of test results for every circuit. Our consumer unit replacement guide explains what else must be checked on the day.
New circuits. A shower circuit from a spare way is a new circuit, however short the run; see our electric shower certificate guide. So is a supply to an outbuilding or an EV charger. EIC every time.
Blank test boxes. "N/A" against Zs or the RCD disconnection time on a socket circuit turns the form into a description of work rather than a certificate. If a test was impracticable, say why in Section A. If you did not test, you cannot sign Section E.
Signing off bonding you did not check. Section B is a Regulation 132.16 declaration. Ticking "gas" and "water" without putting a meter on the bonding conductors is the fastest route to a failed scheme assessment and, if an incident follows, a difficult conversation.
One certificate, several circuits. Regulation 644.4.201 wants one per circuit. If you touched a socket circuit and a lighting circuit, that is two certificates, or an EIC covering both.
Using the MEIWC as a substitute for an EICR. It certifies the altered circuit only. It does not satisfy the five-yearly inspection required of landlords in England under the Electrical Safety Standards in the Private Rented Sector and Social Rented Sector (England) Regulations 2020, where the penalty for non-compliance can reach £40,000. If a landlord asks for "a certificate" after a socket is added, make clear which one they are getting; our guide on EICR vs EIC is written for that conversation.
Not keeping a copy. The customer gets the original; you keep a copy for as long as your scheme and your insurer expect, which for NICEIC-registered firms is six years as a minimum. Our certificate retention guide covers the records side.
How Certio helps
Certio produces the EICR, EIC, Minor Works certificate and PAT records on the BS 7671 model forms and turns them into branded PDFs. Photograph the consumer unit and the circuit schedule drafts itself; point the phone camera at a Megger MFT-X1 and the reading goes straight into the schedule of test results, or dictate it while your hands stay on the probes. Suggested observation wording with the regulation reference is there for you to check and confirm. The judgement stays yours; the typing goes. Starter is £4.99 a month, charged when you sign up.
Sources
- BS 7671:2018+A4:2026 Requirements for Electrical Installations (IET Wiring Regulations), Regulations 132.16, 411.3.3, 411.3.4, 641.5, 643.3, 643.8, 644.1.2, 644.4.201 and Appendix 6
- IET, Model forms for BS 7671:2018+A4:2026: Minor Electrical Installation Works Certificate (15 April 2026) and the A2:2022 version (28 March 2022)
- IET Guidance Note 3: Inspection and Testing, 10th Edition
- NICEIC, "Appropriate use of minor works certificates" (Voltimum, 14 February 2017; Professional Electrician, 25 November 2019)
- SELECT, BS 7671:2018+A4:2026 certification guide and "So what's new?" overview, 2026
- IET, Part P (England and Wales) frequently asked questions; Planning Portal, electrics: building regulations general information; HM Government, Approved Document P (2013 edition, England)
- Electrical Safety Standards in the Private Rented Sector and Social Rented Sector (England) Regulations 2020, as amended
- Electrical Safety First, Best Practice Guide 4, Issue 7.4 (August 2026)