EICR codes tell you how serious each problem found during an electrical inspection is. C1 means danger present and immediate action required; C2 means potentially dangerous and urgent remedial action required; C3 means improvement recommended; and FI means further investigation required without delay. Any C1, C2 or FI makes the report Unsatisfactory – C3s on their own do not.
Understanding the codes helps you read your report with confidence, prioritise work sensibly and spot when a quote does not add up. Here is what each code means in practice.
EICR codes at a glance
| Code | Meaning | Causes a fail? | What to do |
|---|---|---|---|
| C1 | Danger present – immediate action required | Yes | Make safe straight away |
| C2 | Potentially dangerous – urgent remedial action required | Yes | Fix urgently (landlords: within 28 days or sooner if specified) |
| FI | Further investigation required without delay | Yes | Investigate promptly to establish whether there is a danger |
| C3 | Improvement recommended | No | Consider when planning future work |
C1: Danger present
A C1 means there is a risk of injury right now. Someone could get an electric shock or a fire could start without anything else going wrong first. Typical examples include:
- Exposed live conductors, for example a socket or switch with a broken cover that leaves live parts accessible
- Live parts accessible inside an open or damaged consumer unit
- Incorrect polarity that leaves metal parts of an accessory live
- Clear evidence of active burning or arcing
A responsible electrician will not leave a C1 in place. They will either fix it on the spot, isolate the affected circuit or equipment, or – with your agreement – make it safe and explain what permanent repair is needed. You should be told about any C1 before the electrician leaves, not just discover it in the report later.
C2: Potentially dangerous
A C2 is a defect that is not immediately dangerous but would become a danger if something else happened, such as a fault developing on an appliance. It needs urgent attention. Common C2 observations include:
- Absence of main protective bonding to incoming gas or water pipes
- No earthing, or an inadequate earthing arrangement, on a circuit
- Earth fault loop impedance too high for the protective device to disconnect in time
- Cracked or damaged accessories where live parts are not yet exposed
- Signs of overheating at connections or accessories
- Lack of RCD protection in situations where it is particularly needed, depending on the circumstances
For landlords, C2s carry the same legal weight as C1s: they make the report Unsatisfactory and must be put right within 28 days, or sooner if the report says so.
FI: Further investigation required without delay
An FI code is used when the electrician has seen or measured something that suggests a possible danger but could not confirm it within the scope of the inspection. Examples might be test results that point to a fault somewhere on a circuit that cannot be traced during the visit, or a circuit that cannot be identified at all.
An FI is not a “maybe” that can be ignored. It makes the report Unsatisfactory, and for landlords the further investigation falls under the same 28-day rule as remedial work. Once investigated, the issue is either resolved, recoded (for example as a C2 that then needs fixing), or found to be no concern.
C3: Improvement recommended
A C3 means the installation does not meet the current edition of BS 7671 in some respect, but it is not considered dangerous. Installations designed to older standards will often have several C3s, and that is normal. Typical C3 observations include:
- A plastic (combustible) consumer unit in a home – current rules require a non-combustible enclosure for new installations, but an existing plastic unit is generally not a fail on its own
- No RCD protection on some circuits, where the circumstances do not make it a C2
- Missing or incomplete circuit charts and labelling
- Older-style fuses where the installation is otherwise in reasonable condition
There is no legal requirement to fix C3s, but they are worth noting. If you are planning work such as a kitchen refit, it is often efficient to address them at the same time. A consumer unit replacement, for example, can clear several C3s at once.
Why the same issue can get different codes
Coding is a professional judgement, not a lookup table. The same defect can justifiably be coded differently depending on where it is and how the property is used. Missing RCD protection, for instance, is often a C3 in one setting but may be a C2 where there is a higher risk, such as in a location containing a bath or shower without supplementary bonding.
Industry guidance helps electricians code consistently, and a good report explains the reasoning in the observation text. If a code is not clear to you, ask. At Polarity Electrics we attach photos of observations and explain each one, so you can see what we saw.
From 15 October 2026, EICRs are assessed against BS 7671:2018+A4:2026. The change in standard does not mean older installations suddenly fail – each departure is still judged on whether it is actually dangerous. Our Amendment 4 guide explains more.
Spotting over-coding
Most electricians code fairly, but it is reasonable to be cautious if a report lists a large number of C2s with vague descriptions and an expensive repair quote attached. Signs of a well-written report include:
- A specific location for each observation (which room, which circuit)
- A clear description of the defect, not just a regulation number
- Full schedules of test results for every circuit
- Photos of significant defects
If you are unsure, you are entitled to a second opinion from another registered contractor before committing to work.
What to do next
If your report is Satisfactory with only C3s, keep it safe, note the next inspection date and plan improvements at your convenience. If it is Unsatisfactory, read our step-by-step guide to what happens after a failed EICR. New to EICRs altogether? Start with what is an EICR.
Get a clear, well-coded EICR
Polarity Electrics is an NICEIC Approved Contractor carrying out EICRs across London and the Home Counties, from £79 for a studio flat to £149 for a 4-bed house, with no call-out charge. You get a digital certificate the same day, photos and plain-English observations, and a remedial cost breakdown if anything needs fixing. Find out more on our EICR London page, then book online or call 0203 908 4790.
Frequently asked questions
Which EICR codes mean a fail?
Any C1, C2 or FI observation makes the overall report Unsatisfactory. C3 observations on their own do not cause a fail.
Do I have to fix C3 items on an EICR?
There is no legal requirement to fix C3 items, as they are recommendations for improvement rather than dangers. They are still worth considering, especially if you are planning other electrical work.
What does FI mean on an EICR?
FI means further investigation required without delay. The electrician has found something that could be a danger but could not confirm it during the inspection, so it needs investigating before the installation can be considered satisfactory.
How quickly must landlords fix C1 and C2 defects?
Under the 2020 private rented sector regulations, remedial or further investigation work must be completed within 28 days, or sooner if the report specifies. C1 dangers should be made safe immediately, usually during the visit.