EICR Codes Explained: C1, C2, C3, FI and How to Read Your Report

EICR codes describe the inspector’s findings: C1 means danger present, C2 means potentially dangerous, C3 recommends improvement, and FI identifies a need for further investigation. Read each code with its observation to understand the issue affecting your fixed electrical installation.

EICR Certificates London explains how those findings relate to the overall result and your next step. The examples below describe assessment questions, not diagnoses of your property. If you do not yet have a report, book an EICR in London.

What Do C1, C2, C3 and FI Mean?

The codes distinguish immediate danger, potential danger, recommended improvements and matters needing investigation.

Code	Meaning	Urgency	Effect on the report	What happens next
C1	Danger present	Immediate action	Unsatisfactory	A competent electrician makes the danger safe; permanent remedial work follows as necessary.
C2	Potentially dangerous	Urgent attention	Unsatisfactory	Arrange repairs addressing the recorded defect.
C3	Improvement recommended	Plan the recommended improvement	Does not make the result unsatisfactory by itself	Consider the safety benefit and request a separate scope.
FI	Further investigation	Resolve the identified uncertainty promptly	Advisory under the IET A4 model form; see the edition note below	Establish the issue and whether repairs are necessary.

C1: Danger Present and Immediate Action

C1 records an existing danger requiring immediate action. Accessible live parts that someone could touch illustrate this category: the accessibility and actual risk of injury matter. A qualified and competent inspector must inform the person responsible and arrange immediate making-safe; the danger must not remain unresolved. Recording a warning does not complete a repair, and the inspection does not promise that a permanent solution can be finished during that visit.

• Making safe: professional action to remove immediate exposure to danger.
• Permanent repair: correcting the defect and verifying the completed work.

C2: Potentially Dangerous and Urgent Remedial Work

C2 means potentially dangerous and requires urgent remedial work. Lights and sockets can operate normally while an essential protective measure is ineffective. For example, if a circuit protective conductor cannot provide the necessary earth path, a fault could leave accessible metalwork dangerous. The inspector assesses the actual arrangement and supporting test evidence.

The observation should identify the affected circuit, the deficiency and its safety implications. It provides the starting point for remedial work for the C2 observations on your report. The code alone does not specify a replacement consumer unit or determine the extent of repairs.

C3: Improvement Recommended

C3 recommends improvement and does not, by itself, make an EICR unsatisfactory. It identifies an opportunity to improve safety without classifying that observation as dangerous or potentially dangerous. Consider the recommendation when planning maintenance, while remembering that a satisfactory assessment relates to the recorded inspection boundaries and condition at the time.

An electrical works quotation should distinguish required corrections to C1 or C2 findings from recommended C3 improvements, so you can assess each proposed item.

FI: Further Investigation and the Report’s Edition

FI identifies a matter requiring investigation before the inspector can reach a conclusion about it. The observation should explain what remains uncertain and why additional assessment is needed. Arrange fault finding to investigate an FI observation to establish the underlying issue and determine any repair. An access limitation does not automatically justify FI, and an unresolved finding should not be assumed harmless.

How to Read Your EICR Alongside the Codes

A code must be read alongside its observation, the inspection scope and the overall assessment. Use this five-step checklist with the complete report:

1. Confirm the identity: check the property details, inspection date, stated standard and form edition, especially when interpreting FI.
2. Read the boundaries: find the agreed extent, sampling and any operational limitations.
3. Locate each finding: match its wording to a circuit or location. Ask the issuing inspector to clarify an unidentified risk or unclear reference.
4. Check the attachments: locate the inspection schedules, circuit details and schedule of test results.
5. Read the conclusion: compare the recorded outcome with the observations, required actions and next-inspection recommendation.

This original schematic uses placeholders only. Field names and positions vary between report formats.

Why Is My EICR Unsatisfactory?

A C1 or C2 observation makes the installation’s overall assessment unsatisfactory. This is not a points system: satisfactory circuits cannot cancel a dangerous finding elsewhere within the assessed installation. C3-only observations do not produce that outcome. For FI, use the edition-specific explanation above and the issuing inspector’s clarification rather than applying a universal rule.

If your report is unsatisfactory, read what to do if your EICR is unsatisfactory for the practical sequence. “Failed EICR” is an informal description; it does not establish that every circuit needs replacement.

How Quickly Must Coded Problems Be Addressed?

Immediate danger needs immediate action; a landlord’s completion deadline is not permission to postpone urgent work. Under England’s amended framework covering private and social renting, required remedial or investigative work must be completed within 28 days of inspection, or any shorter period specified in the report. See EICR remedial deadlines and landlord requirements in England for the separate document-supply duties described in GOV.UK guidance.

Treat that period as a completion limit, never a waiting period. These landlord deadlines are not universal rules for owner-occupied homes or businesses.

Why the Same Device Can Receive Different EICR Observations

An EICR code depends on the observed condition and safety implications, not simply the equipment’s age or name. BS 7671:2018+A4:2026 is the current technical reference. As IET guidance explains, newer installation requirements do not automatically make older wiring unsafe. The following examples identify questions a competent inspector resolves through periodic inspection and testing; they cannot classify equipment from a photograph.

Missing RCD Protection and Type AC RCDs

Missing RCD protection and an unsuitable RCD type are different observations requiring circuit-specific assessment.

Observation	Context the inspector needs	Why it matters
Absent residual-current protection	If protection is missing, establish the circuit’s use, earthing arrangement and whether an RCD is needed for fault protection or additional protection.	A TT earthing system may rely on residual-current protection for fault disconnection. The safety function must be identified before classification.
Type AC device fitted	If connected equipment produces residual currents the device cannot detect appropriately, examine those characteristics and the manufacturer’s requirements.	Type AC and Type A RCDs respond differently to residual-current waveforms. A marking identifies a type; it cannot settle suitability or coding alone.

The same suitability question applies to residual-current protection within an RCBO. IET guidance on RCD selection explains the relevance of connected loads; trip-time testing and device identification answer different questions.

Does a Plastic Consumer Unit Automatically Fail an EICR?

A plastic enclosure alone does not establish an unsatisfactory EICR result. The inspector considers the consumer unit’s condition, its surroundings and the protective arrangements. The requirement for metal enclosures in new domestic work does not, by itself, identify a dangerous defect in an existing board. An explanatory observation should make the concern clear:

• Is there damage, including overheating at connections?
• Does the location introduce a relevant safety concern?
• Are the enclosure and protective devices adequate for their functions?

Material alone cannot answer those questions or establish a replacement scope.

No SPD: What Determines the Observation?

An absent surge protection device does not provide enough information on its own to assign an EICR code. An SPD limits transient overvoltages that could affect wiring or connected equipment. Assessing an existing installation’s condition differs from specifying protection for new work. The observation should explain the applicable protection and the identified concern, rather than merely list a missing component.

• What surge-protection requirement applies to this installation and its use?
• What risk or deficiency supports the recorded classification?

No AFDD: Why the Premises and Circuit Matter

An AFDD observation must consider the premises, circuit and applicable requirements. An arc fault detection device responds to dangerous arcing. HMO use is one reason property context matters, but neither that label nor a missing device determines the classification. Ask which requirement and safety concern support the finding; an EICR assessment is distinct from a specification for new installation work.

• Confirm the premises’ use and the circuit being assessed.
• Identify the applicable provision and the evidence supporting the observation.

Missing Bonding: Establish What Requires Protection

A bonding observation depends on whether bonding is required and whether the existing protective connection is adequate. Main protective bonding connects relevant external conductive parts to the main earthing terminal; circuit earthing serves electrical equipment. An extraneous-conductive-part can introduce a potential, usually earth potential, from outside the installation. As the IET’s bonding guidance explains, visible metal pipework alone does not settle that assessment.

• Has the inspector established whether the incoming service requires protective bonding?
• What does the report record about the connection’s adequacy and continuity?

A missing visible clamp is not a complete diagnosis.

Get a Quote for EICR Remedial Work in London

EICR Certificates London provides free, no-obligation quotes for remedial and repair work. Have your report, observation schedule, property postcode and any stated completion date ready so the proposed work can be related to the findings. Repairs are quoted according to scope. Open 8am to 10pm, seven days a week.

Call 020 3677 6372 Contact us

Questions About Using Your EICR