Three documents, and picking the wrong one is both an exam error and a real-world problem. The good news is that the test is simpler than most candidates make it.
The three documents
| Document | Regulation | When it applies |
|---|---|---|
| EIC — Electrical Installation Certificate | 644.1 | A new installation, or an addition or alteration that includes replacement of a distribution board or consumer unit |
| MEIWC — Minor Electrical Installation Works Certificate | 644.4.201 | An addition or alteration to an existing circuit that does not include a new circuit or a board/CU replacement |
| EICR — Electrical Installation Condition Report | 653.1 | Periodic inspection of an existing installation |
The test that decides EIC vs Minor Works
This is where people go wrong, and it is worth stating plainly:
The test is not the size of the job, how long it took, or how much it cost. It is whether a new circuit was created, or a distribution board or consumer unit was replaced.
Two examples that make the point:
Adding a socket-outlet to an existing ring final circuit. You ran twenty metres of cable, lifted floorboards, spent most of a day on it. No new circuit. No board replaced. → Minor Works Certificate.
Replacing a consumer unit like for like. Two hours, no new circuits, same number of ways. A consumer unit was replaced. → EIC.
The second one surprises people. It should not: replacing the board means every circuit in the installation has been disturbed, re-terminated and re-tested. That is exactly the situation the fuller certificate exists for.
Note also that Minor Works applies to an alteration to an existing circuit. If the work touches several existing circuits, you are into EIC territory or multiple certificates — one Minor Works Certificate does not cover a whole rewire.
An EICR is never for new work
This one is straightforward but still worth saying. An EICR reports on the condition of an installation that already exists. It records observations with classification codes and reaches an overall assessment of satisfactory or unsatisfactory.
New work is certified, not reported on. If you have just installed something, you are issuing an EIC or a Minor Works Certificate, not an EICR.
What has to accompany a certificate
A certificate on its own is incomplete. Both the EIC and the EICR must be accompanied by:
- a Schedule of Inspections — what was inspected, and the outcome
- a Schedule of Test Results — the measured values, circuit by circuit
These are required parts of the certificate, not optional attachments. An EIC handed over without its schedules is not a complete certificate.
The Minor Works Certificate is self-contained. It has its own space for the limited test results the work requires, because it covers a single circuit alteration rather than an installation.
What goes on the Schedule of Test Results
Circuit by circuit:
- circuit designation, reference method, conductor sizes
- protective device type, rating and short-circuit capacity
- RCD rating and measured operating time, where fitted
- continuity: r1, rn, r2 and R1+R2
- insulation resistance, line-line and line-earth
- polarity confirmed
- measured Zs
Blank cells are read as “not tested”. If a value genuinely could not be obtained, record why. A gap invites the question of whether you forgot; a note saying the circuit was in use and could not be isolated answers it.
Supply characteristics
Every EIC and EICR records what the supply actually is, because it determines what the installation needs:
- earthing arrangement — TN-S, TN-C-S, TT or IT
- number and type of live conductors
- nominal voltage (U₀) and frequency
- Ze at the origin
- PFC at the origin
- the main protective device’s type and rating
Ze and PFC at the origin are measured with the main earthing conductor disconnected from the earthing terminal, which means the installation must be isolated to take them safely. Where you have used a figure supplied by the distributor rather than measured one, say so on the certificate — that is a valid approach, but only if declared.
Who signs, and for what
An EIC carries three declarations: design, construction, and inspection and testing. One person may sign all three; three different people may sign one each.
Signing a section means taking responsibility for it. You cannot sign for design work you did not do and did not see. On a job where you were handed a design and asked to install and test it, you sign two of the three — and the designer signs theirs.
A Minor Works Certificate has a single signature. An EICR is signed by whoever carried out the inspection and testing.
Departures
Where the installation departs from BS 7671, record the departure on the certificate along with the reasoning that makes it safe. A departure is not automatically a defect — the standard allows designs that achieve the same degree of safety by other means — but it has to be declared, not quietly omitted.
The recommended interval
An EIC states a recommended date for the first periodic inspection. An EICR recommends the interval to the next one.
That recommendation is a judgement: the installation’s type, use, age, condition, and the external influences acting on it. A domestic rental, an industrial unit and a caravan site do not get the same answer, and an installation found in poor condition may warrant a shorter interval than its type would normally suggest.
Further reading
The certification and reporting study guide covers all of this in more depth, and the classification and reporting reference cards give you the document-choice table as a quick lookup. There are free certification practice questions when you want to test it.
