A Minor Electrical Installation Works Certificate (MEIWC) is the BS 7671 certificate for additions or alterations to an existing circuit that do not involve installing a new circuit. Adding a socket to an existing ring, extending a lighting circuit for a new fitting, or replacing a damaged length of cable on an existing cooker circuit are all minor works. Installing a new circuit, replacing a consumer unit or rewiring a property are not, and need an Electrical Installation Certificate (EIC) instead. The MEIWC is a short form, but it is a full certificate: it requires real test results for the circuit worked on and confirmation that the existing earthing and bonding are adequate.
- Use an MEIWC for additions or alterations to one existing circuit; never for a new circuit.
- A consumer unit replacement always needs an EIC, not a Minor Works Certificate.
- You must test and record continuity, insulation resistance, polarity, Zs and RCD operation for the altered circuit.
- The form requires you to confirm main protective bonding is present and adequate before you sign.
- Part P notification in England only applies to minor works in special locations such as bathroom zones.
What is a Minor Electrical Installation Works Certificate?
BS 7671 provides three model certificates in Appendix 6: the EIC, the MEIWC and the Electrical Installation Condition Report (EICR). The MEIWC exists because a multi-page EIC with full schedules is disproportionate every time a socket is added, but the work still needs to be inspected, tested and certified under Chapter 64 (initial verification). It is a condensed EIC for a single circuit, signed by one person who takes responsibility for design, construction and inspection and testing.
When should I use a Minor Works Certificate?
The test is simple: has the work added or altered an existing circuit without creating a new one? If yes, and the work is confined to that circuit, the MEIWC is appropriate.
| Job | Correct certificate | Why |
|---|---|---|
| Adding a double socket to an existing ring final circuit | MEIWC | Addition to an existing circuit |
| Replacing a light fitting and running new cable to a new switch position | MEIWC | Alteration to an existing lighting circuit |
| Extending a cooker circuit to a new hob position | MEIWC | Alteration to an existing radial circuit, provided the protective device and cable remain adequate |
| Adding an outdoor socket spurred from a ring, RCD-protected | MEIWC | Addition to an existing circuit; RCD test must be recorded |
| Replacing a damaged section of cable like for like | MEIWC | Repair or alteration to an existing circuit |
| Installing a new circuit for a shower, cooker or EV charger | EIC | New circuit |
| Replacing a consumer unit | EIC | Affects every circuit; full schedule of test results required |
| Full or partial rewire | EIC | New circuits |
| Adding a socket 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 |
Example jobs in detail
Adding a socket. Confirm the circuit type and protective device, and that the socket-outlet is RCD-protected as required by Regulation 411.3.3 for socket-outlets rated up to 32 A. Test the new outlet, record the results and test the RCD. One MEIWC.
Replacing a light fitting with new wiring. Swapping a fitting like for like is usually treated as maintenance. Once you run new cable, add a switch drop or move the point, it is an alteration and needs an MEIWC. Since the 18th Edition (BS 7671:2018), Regulation 411.3.4 has required RCD protection for lighting circuits in domestic premises; if the existing circuit has none, record that as a comment on the existing installation and advise the customer.
Extending a cooker circuit. Moving a cooker connection unit or extending the circuit to a new hob position is an alteration. Check that the existing cable size and protective device remain adequate for the load and the new length; if they need changing, consider whether an EIC is more honest.
Adding an outdoor socket on an RCD. Spurring an outdoor socket from an existing ring is a common minor work. The socket must be RCD-protected under Regulation 411.3.3 and the RCD result recorded. Not notifiable in England; notifiable in Wales.
What must be tested and recorded on a Minor Works Certificate?
The MEIWC model form in BS 7671 Appendix 6 has four main parts, and a scheme assessor will expect every one completed.
Part 1: description of the minor works
Where the work was carried out, a plain description of what was done, the date, and any departures from BS 7671. State the edition of BS 7671 the work complies with; from 15 October 2026 that should be BS 7671:2018+A4:2026 (see Amendment 4: what changes).
Part 2: installation details
The system type (TN-C-S, TN-S or TT), the method of fault protection (normally automatic disconnection of supply), the protective device type and rating for the circuit, and comments on the existing installation. This is where you record anything outside the scope of your work: no RCD protection, undersized bonding, a plastic consumer unit. The form also requires you to confirm that main protective bonding to water, gas and other extraneous-conductive-parts is present and adequate. If it is not, either bring it up to standard (Chapter 54, Section 544) or make the omission clear in writing.
Part 3: essential tests
| Test | What to record | Notes |
|---|---|---|
| Earth continuity | R1+R2 (or R2 where R1+R2 is not practicable) in ohms | Confirms the cpc is continuous to the new point |
| Insulation resistance | Line-line, line-earth and neutral-earth in MΩ at 500 V d.c. | Minimum 1.0 MΩ for a 230 V circuit |
| Polarity | Confirmed correct | Especially important on lighting alterations with switch drops |
| Earth fault loop impedance | Zs in ohms at the furthest point of the altered circuit | Compare against the maximum for the protective device |
| RCD operation | IΔn in mA, operating time in ms at IΔn | Required whenever an RCD provides additional or fault protection for the circuit |
You also need Ze or the prospective fault current at the origin, measured or taken from a recent certificate if you are satisfied it is still valid.
Part 4: declaration
Name, company, scheme registration number where applicable, signature and date. By signing you are taking responsibility for the whole minor work: design, construction and inspection and testing.
How does Part P notification interact with 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. Since April 2013 the notifiable list in England has been: a new circuit, a consumer unit replacement, and additions or alterations to existing circuits in a special location. Special locations for this purpose are essentially bathroom and shower room zones (Section 701 of BS 7671) and rooms containing a swimming pool or sauna.
So most minor works in England are not notifiable: a socket added in a lounge or an outdoor socket on an RCD still needs an MEIWC but no notification. A new shaver socket, extractor fan or downlight within a bathroom zone is notifiable even though the certificate is still an MEIWC. Wales did not adopt the 2013 reduction and retains a broader list including work in kitchens and outdoors.
The MEIWC is your evidence of BS 7671 compliance; the Part P compliance certificate from your scheme is the customer's evidence that the Building Regulations have been met. See Part P notification explained.
What are the common misuses of the Minor Works Certificate?
Scheme assessors and EICR inspectors see the same errors repeatedly.
- Consumer unit changes on a Minor Works Certificate. This is the most common misuse. A consumer unit replacement is a new installation for certification purposes and needs an EIC with a schedule of inspections and a full schedule of test results for every circuit. There is no shortcut. See EIC explained.
- New circuits. A new shower circuit from a spare way is a new circuit, however short. EIC.
- Blank test boxes. "N/A" against Zs or the RCD column makes the form a description of work, not a certificate. If you did not test, you cannot sign.
- Ignoring the bonding question. Signing the bonding as adequate without checking the gas and water bonds is the fastest way to fail a scheme assessment.
- Using the MEIWC to avoid an EICR. It confirms the altered circuit only, and cannot replace the five-yearly EICR required of landlords by the Electrical Safety Standards in the Private Rented Sector (England) Regulations 2020.
- One certificate for many unrelated circuits. The form records one protective device and one set of results. If you touched three circuits, issue three certificates or an EIC.
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 free for 7 days, then £5 a month.