Sources checked · Applies to UK (BS 7671); England for landlord duties
The four codes
| Code | What it means | Overall result | How quickly to act |
|---|---|---|---|
| C1 | Danger present. Risk of injury. | Unsatisfactory | Immediately. The inspector should make it safe before leaving where possible. |
| C2 | Potentially dangerous. Urgent remedial action needed. | Unsatisfactory | Urgently. Landlords: within 28 days or sooner if the report says. |
| FI | Further investigation is advised. | Doesn't change the result on 2026-format reports | Promptly. Landlords: within 28 days if the report requires it. |
| C3 | Improvement recommended. | Doesn't change the result | When convenient. Often worth doing at the same time as other work. |
The wording above is from the model EICR form in BS 7671:2018+A4:2026, the current edition of the UK wiring regulations.
What changed in 2026 for FI
Until 2026, FI read "further investigation required without delay" and an FI made the whole report unsatisfactory. Amendment 4 to BS 7671, published on 15 April 2026, changed the wording to "further investigation is advised" and separated it from C1 and C2, so an FI on its own no longer gives an unsatisfactory result. The IET explains the change in Wiring Matters, July 2026.
The previous version of the regulations can be used until 15 October 2026 (IET). So for a while you may see older-format reports where an FI did make the report unsatisfactory. Check the BS 7671 edition printed on your report.
Landlords: FI still counts towards your 28 days
The rental regulations in England say landlords must carry out any remedial work or further investigation the report requires within 28 days, or sooner if the report says so (the regulations, GOV.UK guidance). That duty hasn't changed. If your report lists an FI, arrange the investigation within the 28 days even though the report is satisfactory.
This point combines the 2026 standard with the 2020 regulations. GOV.UK's guidance still uses the older FI wording, and we've flagged it for professional review.
C1 in more detail
A C1 means someone could be hurt now, for example exposed live parts or a damaged accessory with live conductors showing. A competent inspector won't leave a C1 as it is: they'll make it safe with your agreement, usually by isolating the circuit or removing the item, and record what they did.
C2 in more detail
A C2 isn't dangerous at this moment but would become so if a fault happened. Common examples are a missing or inadequate earth on a circuit, or no main protective bonding to incoming water or gas pipes. These need fixing urgently.
C3 in more detail
A C3 is something that doesn't meet the current edition of BS 7671 but isn't considered dangerous. For example, older wiring colours or a lack of RCD protection on some circuits in certain situations. A report with only C3 items is satisfactory.
Is my report satisfactory?
Look at section E of the report (the summary). On a 2026-format report it will be unsatisfactory if there's at least one C1 or C2. On an older report, an FI will also have made it unsatisfactory.
What to do next
- Read the observations and the inspector's summary, and check the extent and limitations section to see what wasn't inspected.
- If anything is coded C1, C2 or FI, get quotes for the work. Any qualified electrician can do it; you don't have to use the inspector.
- Once the work is done, get written confirmation: usually an Electrical Installation Certificate or Minor Works Certificate for the work.
- Landlords: send that confirmation and the report to your tenants and, if asked, the council within 28 days of the work finishing.
Our guide to what to do after an unsatisfactory EICR goes through this step by step.