EICR C2 vs C3: The Difference That Saves Landlords Hundreds

The gap between C2 and C3 on an EICR is the gap between a mandatory 28-day repair deadline and a note you can file for future reference. Getting this distinction wrong — or having it gotten wrong for you by an electrician who miscodes an observation — can cost hundreds of pounds in unnecessary work.

C2: Potentially Dangerous — Mandatory

A C2 observation means the inspector found a condition that, while not immediately dangerous, could become so under fault conditions. Typical C2 findings include missing RCD protection on socket circuits, evidence of thermal damage, and circuits with inadequate fault-current paths.

Any C2 makes the overall EICR unsatisfactory. You have 28 days, or any shorter period specified in the report, to complete the repair and obtain written confirmation from the electrician.

C3: Improvement Recommended — Advisory

A C3 means the installation does not meet the current edition of BS 7671 wiring regulations in one respect, but there is no present or potential danger. The overall report stays satisfactory. There is no legal obligation to act on a C3 under SI 2020/312.

Common C3 observations include the absence of Arc Fault Detection Devices (AFDDs), lack of surge protection, or bonding arrangements that meet previous editions but not the 18th Edition.

Why the Distinction Matters

A consumer unit replacement to add AFDD protection costs between £450 and £900. If the only finding on your report is that the board lacks AFDDs — a feature that did not exist when most boards were installed — that should be a C3, not a C2. BS 7671 wiring standards are not retrospective. An installation that was compliant when fitted does not fail solely because a new edition introduced a feature it never had.

When to Question a C2

Landlord forums are full of reports of electricians coding C3-level observations as C2, whether from genuine caution or because a C2 creates follow-on work. If your report has a C2 for a feature your installation was never designed to include — AFDDs, surge protection devices, or supplementary bonding that was removed as a requirement years ago — it is worth getting a second opinion from another qualified inspector before authorising the work.

This is not about cutting corners. If the C2 reflects a genuine safety defect — missing earthing, overloaded circuits, evidence of arcing — fix it immediately. The question is only whether the code accurately reflects the level of risk.

What a Second Opinion Looks Like

Ask another inspector registered with NICEIC, NAPIT, or the Registered Competent Person Electrical scheme to review the report. They can confirm whether the code is appropriate or whether the observation should have been classified differently. The cost of a review (often £50–£100) is trivial compared to an unnecessary £800 board swap.

The Electrical Safety (EICR) Compliance Guide includes a classification code action map that helps you identify which findings are mandatory and which are advisory, with specific guidance on the C3-to-C2 miscoding trap.

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