Can I use a Minor Works Certificate for a new circuit?

No. A Minor Electrical Installation Works Certificate is limited to additions and alterations to an existing circuit. A new circuit, however small, needs an Electrical Installation Certificate with a full schedule of test results. This is the single most common certification error picked up at scheme assessments.

What tests are needed on a Minor Works Certificate?

Continuity of the protective conductor (R1+R2 or R2), insulation resistance, polarity, earth fault loop impedance (Zs) at the furthest point of the altered circuit, and RCD operating time where the circuit is RCD protected. Ring final circuits also need continuity of r1, rn and r2 if the ring was broken into.

Does a Minor Works Certificate need to be notified under Part P?

Usually not, because most minor works are not notifiable. Since 2013 in England, work in a bathroom or kitchen is only notifiable if it involves a new circuit or a consumer unit. If minor works are notifiable, a registered electrician notifies through their scheme and the client receives a separate Building Regulations certificate.

Can I put more than one circuit on a Minor Works Certificate?

The BS 7671 model form is designed for work on one circuit. Where an alteration touches two circuits, such as moving a socket-outlet and a light on separate circuits, the safest approach is a certificate per circuit, or an EIC covering the whole job. Some scheme forms allow multiple circuits; the model form does not.

Do I need a Minor Works Certificate for replacing a socket?

For a like-for-like replacement of an accessory, BS 7671 still requires the work to be inspected and tested, and a Minor Works Certificate is the appropriate record. Most scheme guidance treats replacing a damaged accessory as minor works and expects a certificate, including a Zs reading at the replaced point.

What is a Minor Works Certificate? MEIWC explained

A Minor Electrical Installation Works Certificate (MEIWC, usually called a Minor Works Certificate) is the BS 7671 certificate issued for an addition or alteration to a single existing circuit that does not include a new circuit, such as adding a socket-outlet, extending a lighting circuit or replacing an accessory. It records the essential tests for that circuit on a single page and, like the EIC, confirms the work complies with BS 7671:2018+A4:2026, the edition in force since 15 April 2026.

Key takeaways

Use a Minor Works Certificate for additions and alterations to one existing circuit only.
A new circuit or a consumer unit change always needs an EIC.
The certificate still requires test results: continuity, insulation resistance, polarity, Zs and RCD time.
Most minor works are not notifiable under Part P, but some are.

What is a Minor Works Certificate in practice?

BS 7671 Chapter 64 requires that every addition or alteration is inspected and tested and does not impair the safety of the existing installation. For small jobs a full EIC with separate schedules would be disproportionate, so Appendix 6 provides a one-page certificate combining the description of the work, the essential test results and the declaration. It is designed for one circuit, and it is not a lighter EIC to be used whenever the job is small.

When is a Minor Works Certificate used?

Work	Minor Works Certificate?
Adding a socket-outlet to an existing ring final circuit	Yes
Adding a light or switch to an existing lighting circuit	Yes
Replacing a damaged accessory or a light fitting	Yes
Adding an RCD or RCBO to protect an existing circuit	Yes, if only one circuit is affected
New circuit of any kind	No, EIC required
Consumer unit replacement	No, EIC required
Rewiring a circuit from the board	No, EIC required

Part P of the Building Regulations in England and Wales adds a second question: is the work notifiable? In England, since April 2013, that means a new circuit, a consumer unit replacement, or an addition or alteration in a special location such as a bathroom; Wales retains broader rules. Notifiable minor works are still certified on a Minor Works Certificate, with the notification going through the scheme.

What does a Minor Works Certificate contain?

The model form has four parts:

Description of the minor works: the installation address, a description of the work, the date completed, and any departures from BS 7671 with the client's agreement.
Installation details: the earthing system (TN-S, TN-C-S or TT), the method of fault protection, the protective device type and rating for the circuit, and comments on the existing installation including whether main protective bonding is present and adequate.
Essential tests: earth continuity (R1+R2 or R2), ring continuity (r1, rn, r2) where relevant, insulation resistance line-to-line and line-to-earth in megohms, polarity, earth fault loop impedance Zs in ohms, and RCD operating time in milliseconds at the rated residual current.
Declaration: name, signature, position, company and date of the person responsible.

Insulation resistance is tested at 500 V DC for a 230 V circuit, with a BS 7671 minimum of 1 MΩ. Zs is measured at the furthest point of the altered circuit and compared against the maximum in BS 7671 Chapter 41 for the protective device.

Common mistakes with Minor Works Certificates

Using it for a new circuit. A new cable from the board is a new circuit. Use an EIC.
Skipping the comments on the existing installation. If you extend a circuit from a board with no main bonding, say so; Best Practice Guide 4 treats that as potentially dangerous.
Recording Zs without testing it. Measure at the new point, not from the previous certificate.
Not testing the RCD. If the addition brings a socket-outlet into the scope of Regulation 411.3.3 (30 mA RCD protection for sockets up to 32 A), fit the protection or record the departure.
Multiple circuits on one form. Issue a certificate per circuit or an EIC.

Related terms

How Certio helps

Certio records this on the BS 7671 model forms without the typing: photograph the board to draft the circuit schedule, point the camera at a Megger MFT-X1 to capture readings, or dictate them. Starter is free for 7 days.

Written by the Certio team. Last checked 14 September 2026.