A Minor Electrical Installation Works Certificate (MEIWC, or Minor Works Certificate) is the BS 7671 certificate for an addition or alteration to one existing circuit that does not involve a new circuit: an extra socket-outlet on a ring, a new lighting point, a replaced accessory or a like-for-like protective device swap. The current model form, dated 15 April 2026 for BS 7671:2018+A4:2026, is laid out in five Sections, A to E, and must be issued per circuit altered (Regulation 644.4.201). It records the essential test results for that circuit and carries the same declaration of compliance as an EIC, so it is a certificate in its own right, not a lighter EIC for small jobs.
- A MEIWC covers additions and alterations to a single existing circuit. New circuits, consumer unit replacements and distribution board changes need an Electrical Installation Certificate (EIC).
- The A4:2026 form has Sections A to E: description of the works, earthing and bonding, circuit details, test results, and declaration. The old "Parts 1 to 4" layout has gone.
- One certificate per circuit. Several accessories on the same circuit can share a form; two circuits cannot.
- Tests are not optional. Section D asks for continuity, insulation resistance, polarity, Zs, RCD time at IΔn and test-button checks, with AFDD and SPD boxes new on the A4 form.
- Most minor works are not notifiable under Part P in England, but the Welsh list is wider and anything in a bathroom zone is notifiable in both.
What does MEIWC stand for and what is it for?
MEIWC stands for Minor Electrical Installation Works Certificate. It is one of the three certification documents in Appendix 6 of BS 7671, alongside the Electrical Installation Certificate (EIC) and the Electrical Installation Condition Report (EICR). Chapter 64 requires every addition and alteration to be inspected and tested and to be shown not to impair the safety of the existing installation (Regulation 641.5), and the MEIWC is the form that records this for small jobs.
The scope line on the IET model form is the definition that matters: "To be used only for minor electrical work which does not include the provision of a new circuit." The form's notes add that it may be used for replacing accessories or luminaires, but not for consumer units or distribution boards. Everything else about using the certificate correctly flows from those two sentences.
The test is the work, not the invoice value. A single socket-outlet fed by a new cable from the board is a new circuit and needs an EIC; twenty metres of new lighting cable looped from an existing switch is minor works. As one contributor to the IET EngX thread "EIC or MWC?" put it, the work determines whether it is minor, and if the work is not minor the paperwork cannot make it so.
When can you use a Minor Works Certificate?
NICEIC published "Appropriate use of Minor Works Certificates" (Voltimum, 14 February 2017, repeated in Professional Electrician in November 2019) and it remains the clearest scheme guidance on the line between a MEIWC and an EIC. The table below combines that guidance with the wording of the A4 form.
| Work | Certificate | Why |
|---|---|---|
| Adding a socket-outlet to an existing ring final or radial | MEIWC | Addition to one existing circuit |
| Adding a lighting point or moving a switch | MEIWC | Named in the form's notes as typical minor work |
| Replacing a damaged accessory or a luminaire | MEIWC | Form notes allow replacement of accessories and luminaires |
| Several accessories on the same circuit | One MEIWC | One certificate per circuit, not per accessory (NICEIC) |
| Like-for-like replacement of a single MCB or RCD | MEIWC | NICEIC: single device swap after the Regulation 132.16 checks |
| MCB replaced by an RCBO, or a Type C device changed to Type B | MEIWC | Allowed if you verify disconnection under fault and overload (NICEIC) |
| Replacing an RCD that provides fault protection on a TT system | MEIWC | Only after checking electrode, earthing conductor and bonding (NICEIC) |
| Installing or upgrading main or supplementary bonding | MEIWC | One certificate per location where bonding is done (NICEIC) |
| Work on two or more circuits | One MEIWC per circuit, or an EIC | Regulation 644.4.201 |
| New circuit of any size | EIC | Excluded by the form's scope line |
| Consumer unit or distribution board replacement | EIC | Excluded by the form's notes |
| Rewiring a circuit from the board | EIC | A replaced circuit is a new circuit |
Two points from the NICEIC guidance are worth keeping in mind. First, before any addition or alteration, Regulation 132.16 requires you to assess whether the existing installation can take the altered conditions: earthing, bonding, protective devices and maximum demand. Second, if the device you swap is not like-for-like, the onus is on you to verify that the new device still disconnects within the Chapter 41 times for the circuit's measured Zs, and the MEIWC is where that Zs is recorded.
What does the A4:2026 Minor Works form contain?
The IET's A4 model MEIWC (bs7671_meiwc_a4.pdf, dated 15 April 2026) replaced the A2 form dated 28 March 2022 when Amendments 2 and 3 were withdrawn on 15 October 2026. The old "Part 1 to Part 4" layout is gone; the A4 form is in five lettered Sections, matching the EIC and EICR.
| Section | Title | What it asks for |
|---|---|---|
| A | Description of the minor works | Client, date completed, installation address, description of the works, departures from BS 7671 (Regs 120.3, 133.1.2, 133.1.3, 133.5), permitted exceptions under 411.3.3 with a "risk assessment attached" box, and comments on the existing installation including defects observed (Reg 644.1.2) |
| B | Earthing and bonding (Reg 132.16) | System earthing: 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 or other |
| C | Circuit details | DB reference and location, circuit number and description, reference method (Table 4A2), live and cpc csa; overcurrent device BS (EN), type, rating and breaking capacity in kA; RCD BS (EN), type, rating, IΔn and rated time delay; AFDD BS (EN) and rating; SPD BS (EN) and type |
| D | Test results (where relevant and practicable) | R1+R2 or R2; r1, rn, r2; insulation resistance with test voltage, live-live and live-earth; polarity; maximum measured Zs; RCD disconnection time at IΔn; RCD test button; AFDD test button; SPD functionality confirmed |
| E | Declaration | "I certify that the work covered by this certificate does not impair the safety of the existing installation", designed, constructed, inspected and tested to "BS 7671:2018 amended to [date]", complied except as detailed in Section A; name, for/on behalf of, address, signature, position, date |
What changed from the A2 form, in practice:
- Section B records Zdb, the loop impedance at the distribution board, rather than Ze at the origin. That is a sensible change for minor works, because you rarely open the origin for a socket addition, but it means the figure you enter is the one measured at the board feeding the circuit.
- TN-C-S is split into PME and PNB. If the DNO has told you the supply is PNB rather than PME, say so.
- The overcurrent device now needs its breaking capacity in kA, and the RCD its rated time delay. Both come straight off the device label.
- AFDD and SPD boxes are new in Sections C and D. If the circuit has an AFDD, you press its test button; the form notes that not every AFDD has one. If the board has an SPD, you confirm its status indicator; again, not every SPD has visible indication.
- Section A gives Regulation 411.3.3 its own box for the permitted exceptions to 30 mA RCD protection of socket-outlets, with a tick for a risk assessment attached.
The form has no "next inspection" field. That lives on the EIC and the EICR, not on minor works.
What tests go on a Minor Works Certificate?
Section D is headed "where relevant and practicable", which is not a licence to leave it blank. For a typical socket addition on a ring final circuit every row applies. The limits below come from BS 7671:2018+A4:2026 and IET Guidance Note 3 (10th Edition).
| Test | What the form wants | Limit or check |
|---|---|---|
| Protective conductor continuity | R1+R2 (or R2 where R1+R2 is impractical) in Ω | Compare with the expected value for the conductor sizes and length; used to check Zs |
| Ring continuity | r1, rn, r2 in Ω if the ring was broken into | r1 and rn similar; r2 ≈ 1.67 × r1 for 2.5/1.5 mm² cable |
| Insulation resistance | Test voltage, live-live and live-earth in MΩ | 500 V d.c. for a 230 V circuit, minimum 1 MΩ (Table 64), GN3 flags under 2 MΩ as worth investigating |
| Polarity | Satisfactory | Reg 643.6: every single-pole device in the line conductor, centre contact of E14/E27 lampholders excepted |
| Earth fault loop impedance | Maximum measured Zs in Ω at the furthest point | Within 80 % of the Chapter 41 maximum for the device (see the maximum Zs guide) |
| RCD disconnection time | ms at IΔn | Reg 643.8: 300 ms maximum for a general 30 mA device; the 5× and ½× tests have not been required since A2:2022 |
| RCD test button | Satisfactory operation | Press it |
| AFDD test button | Satisfactory operation where fitted | Press it, where the device has one |
| SPD | Functionality confirmed where fitted | Status indicator shows healthy |
Two practical points. The insulation resistance figure should be the altered circuit measured in isolation, not the whole board; a board-wide reading of 2 MΩ across ten circuits tells you nothing about the one you have worked on. And the Zs must be measured at the new point, not copied from the last certificate; a socket added at the far end of a long radial can take the circuit over the limit even when the board end was fine. Readings can go straight from the instrument into the form by photographing a Megger MFT-X1 display or by dictation, but the measurement itself still has to be made.
Is minor work notifiable under Part P?
Part P of the Building Regulations applies in England and Wales only; Scotland uses the Building (Scotland) Regulations and its approved certifier schemes. Whether the work is notifiable is a separate question from which certificate to issue: a notifiable job is still certified on a MEIWC if it is minor works, with the Building Regulations notification made through your competent person scheme. GOV.UK Approved Document P and the Planning Portal set the lists.
| Work | England (since 6 April 2013) | Wales |
|---|---|---|
| Extra socket or lighting point in a living room or bedroom | Not notifiable | Not notifiable |
| Extra socket or light in a kitchen | Not notifiable | Notifiable |
| Any addition or alteration inside a bathroom zone | Notifiable | Notifiable |
| Outdoor socket or lighting fed from an existing circuit | Not notifiable | Notifiable |
| Like-for-like accessory or device replacement | Not notifiable | Not notifiable |
| New circuit or consumer unit replacement | Notifiable, and an EIC job | Notifiable, and an EIC job |
Wales kept the original 2005 list when England cut it down in 2013, so the same kitchen socket is notifiable on one side of the border and not the other. If you are not registered with a scheme, notifiable work has to go through building control before it starts, so the "not notifiable" rows matter most to electricians working outside a scheme. See the Part P notification guide for the registration routes.
Common Minor Works Certificate mistakes
Scheme assessors see the same errors on MEIWCs year after year. These are the ones that get picked up, and what to do instead.
- Using it for a new circuit. A new cable from the board is a new circuit however short it is. Use an EIC. This is the single most common certification error at assessment.
- Using it for a consumer unit change. Excluded by the form's own notes. A board change re-terminates and re-protects every circuit, so the consumer unit replacement guide applies and the certificate is an EIC.
- Putting two circuits on one form. Regulation 644.4.201 says one certificate per circuit. Issue two, or use an EIC with a schedule covering both.
- Leaving Section A item 5 blank. The comments on the existing installation are where you record that the board has no main bonding, that the earthing conductor is undersized or that the existing RCD failed its test. Electrical Safety First Best Practice Guide 4 (Issue 7.4, August 2026) treats missing main bonding as C2 territory on an EICR; on a MEIWC you still record it and tell the client.
- Zs without a test. Measure at the new point. The form says "maximum measured", not "assumed".
- Not fitting or recording RCD protection. A socket-outlet up to 32 A added on a circuit without 30 mA RCD protection brings Regulation 411.3.3 into play. Either fit the protection, usually an RCBO on that circuit, or record the permitted exception with a risk assessment in Section A.
- Signing on a form that is out of date. From 15 October 2026 the A2 form is withdrawn. The declaration must read "BS 7671:2018 amended to" with a 2026 date; a form still laid out in Parts 1 to 4 is the old one.
Minor Works Certificate vs EIC vs EICR
| MEIWC | EIC | EICR | |
|---|---|---|---|
| Purpose | Certify an addition or alteration to one existing circuit | Certify new work: a new installation, new circuit or board change | Report on the condition of an existing installation |
| Issued when | Minor work complete | New work complete | Periodic inspection or change of occupancy |
| Covers | One circuit | Whole job, any number of circuits | Whole installation or an agreed sample |
| Schedules | None; test results in Section D | Schedule of inspections and schedule of test results | Schedule of inspections and schedule of test results, plus observations C1, C2, C3, FI |
| Next inspection field | No | Yes (Reg 134.2.2) | Yes (Reg 652) |
| Outcome | Compliance declaration | Compliance declaration | Satisfactory or unsatisfactory |
If you are unsure which of the first two applies, the EICR vs EIC guide covers the condition-report side and the Minor Works: when to use it guide works through the borderline cases in more depth, including the NICEIC examples and the Scotland and Wales differences.
Related terms
- Electrical Installation Certificate (EIC)
- EICR
- Earth fault loop impedance (Zs)
- RCD
- AFDD
- Main protective bonding
- Schedule of test results
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.