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Understanding EICR Classification Codes: C1, C2, C3, and FI
EICR GuidesEssential8 min read

Understanding EICR Classification Codes: C1, C2, C3, and FI

A detailed explanation of each EICR classification code with real-world examples. Learn what C1 (danger present), C2 (potentially dangerous), C3 (improvement recommended), and FI (further investigation) mean for your property.

Why Classification Codes Matter

Every EICR certificate uses a classification system to grade the severity of defects found during inspection. These codes are not suggestions — they are a legal and safety grading that determines whether your property is satisfactory, what remedial work is required, and how urgently it must be done. Misunderstanding these codes can lead to compliance failures, insurance issues, and most seriously, tenant injury.

This guide breaks down each code with real-world examples from properties we've inspected across Manchester and Stockport. We explain what each code means, what action is required, typical causes, and what you can expect to pay for remedial work.

The Golden Rule

A satisfactory EICR can contain only C3 codes. Any C1, C2, or FI code makes the installation unsatisfactory and requires remedial action before the property can be certified safe.

C1 — Danger Present

A C1 code means there is a real and immediate risk of electric shock or fire. The inspector should make the installation safe immediately if possible, or advise you to isolate the affected circuit until remedial work is completed. Common causes of C1 codes include exposed live conductors, missing earth connections, and damaged accessories with visible conductors.

  • Exposed live parts accessible to touch — e.g. broken socket with visible terminals
  • Missing or broken earth bonding on gas or water pipes
  • Consumer unit with visible burn marks or melted components
  • Socket back-boxes with live terminals touching metalwork
  • Damaged cables with insulation stripped exposing conductors
  • Incorrect polarity at socket outlets creating shock risk
Immediate Action Required

C1 codes require immediate remedial action. Do not delay. If tenants are present, inform them immediately and isolate the affected circuits. Call a registered electrician the same day.

C2 — Potentially Dangerous

A C2 code indicates conditions that are not immediately dangerous but could become hazardous under certain circumstances. You have 28 days to complete remedial work (or the deadline specified on the report). C2 codes are the most common cause of unsatisfactory EICRs and typically relate to the absence of RCD protection, outdated consumer units, and inadequate earthing.

  • Absence of RCD protection on socket circuits — most common C2 on pre-2008 properties
  • Plastic consumer unit without fire-resistant barriers — post-Amendment 2 requirement
  • Inadequate earthing or high earth electrode resistance
  • Overloaded circuits without proper protective device rating
  • Absence of supplementary bonding in bathrooms (pre-2022 installations)
  • Cables with deteriorated insulation but conductors not yet exposed
Typical C2 Remedial Work

RCD addition, consumer unit replacement, earthing improvements, and supplementary bonding are the most common remedial tasks. We provide a detailed quote for all work before any remedial work begins.

C3 — Improvement Recommended

C3 codes are advisory only. They do not make an EICR unsatisfactory and do not require mandatory remedial action. However, addressing C3 items improves safety, future-proofs the installation, and can prevent them from becoming C2 codes in future inspections. Common C3 codes include missing labels, outdated but still functional equipment, and non-essential upgrades.

  • Missing or illegible circuit labels on the consumer unit
  • Absence of arc fault detection devices (AFDDs) — recommended but not mandatory
  • Socket outlets without shutters (pre-1994 installations)
  • Non-compliant cable routing that does not meet current best practice
  • Absence of surge protection devices (SPDs) on installations where desirable
Smart Investment

While not mandatory, fixing C3 items during the same visit as C2 remedial work is usually cheaper than calling an electrician back later. Ask for a combined quote.

FI — Further Investigation Required

An FI code means the inspector could not fully assess an aspect of the installation and requires further investigation before a complete safety assessment can be made. FI codes make the EICR unsatisfactory because the installation cannot be fully verified as safe until the investigation is completed.

  • Inaccessible parts of the installation behind fixed panels or built-in furniture
  • Cables of unknown origin or routing that cannot be traced
  • Historic alterations without documentation — unable to verify compliance
  • Underfloor or loft circuits that could not be safely accessed during inspection
  • Imported or non-standard equipment without UK certification marks
Resolving FI Codes

FI codes are usually resolved by providing access, tracing unknown circuits, or replacing non-compliant equipment. Once investigated, the FI is either cleared or downgraded to a C2 or C3.

What the Overall Assessment Means

At the end of your EICR, the inspector provides an overall assessment: either 'satisfactory' or 'unsatisfactory'. This summary is what councils, insurers, and letting agents look at first.

Satisfactory means no C1, C2, or FI codes are present. The installation is safe for continued use, subject to any C3 recommendations. Unsatisfactory means at least one C1, C2, or FI code exists, and remedial action is required before the installation can be considered safe. You must complete remedial work, obtain confirmation from the electrician, and provide this to tenants and the local authority if requested.

Need Help With Your Property?

Our NAPIT-registered team provides EICR inspections, fire alarm testing, and ventilation assessments across Manchester and Stockport. Call or message us for a no-obligation quote.

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