EICR Classification Codes Explained: C1, C2, C3 and FI for Landlords

You get your EICR back and it is covered in codes — C1, C2, C3, FI — with no clear explanation of what each one actually requires from you. Understanding the difference between a code that demands immediate action and one that is purely advisory is the single most important thing a landlord can learn about electrical compliance.

C1 — Danger Present

A C1 means the inspector found an immediate risk of injury: exposed live conductors, severely damaged cables, or a shock hazard that could hurt someone right now. The inspector may make the situation safe on site — typically by isolating the affected circuit — before they leave. You then have 28 days (or less, if the inspector specifies) to have the underlying defect properly repaired.

A C1 makes the overall report unsatisfactory.

C2 — Potentially Dangerous

A C2 flags a serious defect that is not immediately dangerous but could become so under fault conditions. The most common examples are absence of RCD protection on socket circuits, overloaded circuits, and thermal damage to components. Complete the repair within 28 days of the inspection date, or within any shorter period specified in the report.

A C2 also makes the report unsatisfactory.

FI — Further Investigation Required

An FI means the inspector could not determine safety without deeper access or more extensive testing — a concealed junction box they could not reach, or a circuit that needs load testing under conditions they could not create during the visit. You authorise the investigation, which must be completed within 28 days of the inspection date or any shorter period specified in the report. If it reveals a C1 or C2 defect, the 28-day remedial clock starts from the date the investigation report is completed.

Any FI code makes the report unsatisfactory.

C3 — Improvement Recommended

A C3 is advisory. The installation does not meet the current edition of BS 7671 in that respect, but there is no danger — present or potential. The overall report remains satisfactory despite C3 observations, and there is no legal obligation to carry out the recommended work under SI 2020/312.

This is where the confusion costs landlords money. A C3 on an older consumer unit that lacks modern features (like arc fault detection) is a recommendation, not a failure. It does not trigger the 28-day remedial window, it does not make the report unsatisfactory, and it does not require a consumer unit replacement.

The Trap Between C2 and C3

Some electricians code advisory items as C2 instead of C3 — whether through genuine disagreement about risk or because a C2 creates repair work. If you receive a C2 for a feature your installation never had (like AFDDs on an older board), that may warrant a second opinion. BS 7671 wiring standards are not retroactive: an installation that was compliant when built does not fail simply because a newer edition added new requirements.

The Electrical Safety (EICR) Compliance Guide includes a code-by-code action map and a framework for evaluating whether a C2 finding is a genuine defect or an advisory that should have been coded C3.

See more England guides →