Minor electrical installation works certificate: when it applies and when you need a full EIC

Published 26 March 2026 · updated 10 June 2026 · SparkCerts guides for UK electricians

The minor electrical installation works certificate is the most issued and most misused form in BS 7671. Issued for the right job, it is exactly proportionate: one altered circuit, one page, tested and signed. Issued for the wrong job, it is a full rewire hiding behind a single sheet of paper. The line between the two is precise, and it is worth knowing exactly where it sits.

What a minor works certificate covers

One certificate covers an addition or alteration to a single existing circuit that does not extend to a new circuit. The everyday examples:

• Adding a socket outlet to an existing ring or radial
• Adding a fused spur for an appliance
• Replacing or relocating a light fitting, adding a switch drop
• Moving an accessory during decorating or a kitchen refit
• Replacing a damaged accessory where the circuit itself is sound

Several alterations on the same circuit during the same visit can sit on one certificate. Alterations to two different circuits need two certificates, one each, because the test results belong to a circuit.

When the job needs a full EIC instead

BS 7671 draws the line at the new circuit. The moment the work involves one, the minor works form is the wrong document and a full electrical installation certificate is required. In practice that means:

• Any new circuit from the board, however short
• A consumer unit replacement, which re-certifies every circuit in the property
• A new shower, hob or EV charger circuit
• Work within the scope of a special location, such as a bathroom zone, where the extent of the work goes beyond like-for-like

What has to be recorded

The form is short and every field on it earns its place: a description of the minor works, the circuit altered, the earthing and bonding checked at the point of work, and the test results for the altered circuit. The tests are the same family as an EIC schedule: continuity, insulation resistance, polarity, earth fault loop impedance, and RCD operation where the circuit relies on one. If a reading cannot be right, the time to notice is on site. Our note on certificate software that checks readings as you type covers how the better tools flag an implausible Zs before the form is signed.

The misuse that catches people out

Assessment day folklore is full of minor works certificates stretched over jobs they cannot carry: a new kitchen circuit on a minor works form, a board change with no schedule of test results, three circuits altered on one sheet. The form is not a shortcut around certification, it is the proportionate version of it. When the scope of a job grows mid-visit, the paperwork grows with it, and the customer should hear that at the moment the scope changes rather than at invoice time.

Common questions

What counts as minor electrical works?

Additions or alterations to an existing circuit that do not include a new circuit: an extra socket on a ring, a replacement light fitting on a new switch drop, moving an accessory. New circuits always need a full electrical installation certificate.

Can I issue a minor works certificate for a consumer unit change?

No. A consumer unit replacement affects every circuit in the installation and requires a full EIC with the schedule of test results for each circuit reconnected.

Does a minor works certificate need test results?

Yes. The form records earth continuity, insulation resistance, polarity, earth fault loop impedance and RCD operation for the altered circuit. A minor works certificate without readings is just a receipt.