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Understanding Your Report

EICR codes explained: C1, C2, C3 and FI

Every observation on an EICR is given a classification code. Knowing what C1, C2, C3 and FI mean tells you whether your report has passed, what you must fix and how urgently.

Updated 8 October 2026•7-minute read•By Polarity Electrics London Ltd (NICEIC Approved Contractor)

The four EICR codes at a glance

C1

Danger present

Risk of injury now – for example exposed live parts. Unsatisfactory. The inspector should make it safe before leaving where possible.

C2

Potentially dangerous

Could become dangerous under a fault – for example no RCD protection for sockets that may supply outdoor equipment, or a missing main bonding conductor. Unsatisfactory.

C3

Improvement recommended

Not dangerous, but would improve safety – for example a plastic consumer unit in an older installation. A C3 alone does not fail the report.

FI

Further investigation

The inspector found something that needs investigating before it can be classified, such as an unidentified circuit or unexpected test result. Treated as requiring action.

CodeMeaningReport outcomeAction
C1Danger present – risk of injuryUnsatisfactoryImmediate – make safe now
C2Potentially dangerousUnsatisfactoryUrgent – within 28 days for landlords
FIFurther investigation required without delayUnsatisfactoryInvestigate within 28 days for landlords
C3Improvement recommendedDoes not fail the reportOptional, but advised

C1 – Danger present

A C1 means there is a present risk of injury. Typical examples are exposed live conductors, a broken socket with live parts accessible, or incorrect polarity that leaves a fitting live when switched off. The inspector should make the situation safe straight away – by isolating the circuit or removing the hazard – and tell you in writing.

C2 – Potentially dangerous

A C2 means the installation is not immediately dangerous but would become so if a fault occurred. Common C2 examples include:

  • No RCD protection for socket outlets likely to supply equipment outdoors.
  • Absence of main protective bonding to incoming gas or water services.
  • Inadequate earthing or high earth fault loop impedance.
  • Signs of overheating or thermal damage at accessories or the consumer unit.
  • Unsuitable accessories within bathroom zones.

C3 – Improvement recommended

C3 observations do not make the installation unsafe. They highlight where the installation does not meet the current edition of BS 7671 but was compliant when installed – for example, a consumer unit with a plastic enclosure, or lack of RCD protection on lighting circuits in some older installations. Fixing C3 items is optional, though often worthwhile when other work is being done.

FI – Further investigation required

FI is used when the inspector has found something that cannot be fully assessed within the scope of the inspection – for instance a circuit that could not be traced, or a test result that suggests a hidden fault. FI makes the report unsatisfactory until the investigation is done and any resulting issue is resolved.

What to do once you know the codes

If your report contains C1, C2 or FI, follow our failed EICR action plan. Landlords must complete the work within 28 days and provide written confirmation to tenants and the council. If you are unsure whether a code is appropriate, ask the inspector to explain it or get a second opinion from another registered electrician.

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Frequently asked questions

Which EICR codes mean a fail?

C1, C2 and FI all make the report unsatisfactory. C3 on its own does not.

Is no RCD a C2 or C3?

It depends on the circuit. Missing RCD protection for sockets that may supply outdoor equipment, or for circuits in a bathroom, is commonly coded C2. Missing RCD protection on some other circuits in an older installation may be a C3. The inspector's judgement and the guidance from the registration bodies apply.

Is a plastic consumer unit a fail?

Not usually. A plastic consumer unit installed before the 2016 amendment is normally coded C3 (improvement recommended) unless it is damaged or located in an escape route without other fire protection.

Landlord EICR requirements: the rules explainedEvery legal duty under the Electrical Safety Standards Regulations 2020, with deadlines and penalties.Failed EICR: what to do after an unsatisfactory reportYour 28-day action plan after an unsatisfactory EICR, with typical remedial costs.How often do you need an EICR?Recommended EICR renewal intervals for every property type, from flats to factories.

Sources

This guide summarises current requirements and common inspection practice. It does not replace legal advice, the findings of your report or current legislation.