EICR Codes Explained: C1, C2 and C3

You've received your EICR and it's come back Unsatisfactory. The report lists some observations and codes you've never seen before. Here's exactly what C1, C2 and C3 mean — and what you're required to do about each one.

Understanding the Classification System

Every defect or departure from the current wiring regulations found during an EICR is given one of three codes. These codes indicate how serious the finding is, not how expensive it is to fix. A C1 might be a simple repair; a C3 might involve significant work but is still only advisory.

C1 — Danger Present, Immediate Action Required

A C1 means the electrician found a condition that poses immediate danger. Examples include: live parts that can be touched without tools, damaged or degraded wiring with exposed conductors, an RCD that has completely failed its test, or a significant reversal of polarity on the mains supply.

If your report contains a C1, the property should not be used in its current state. For landlords, this means the property should not be rented until the fault has been fixed. For homeowners, take the advice of the electrician seriously — C1s are rare but when they appear it's for good reason.

Legally, landlords must have C1 items addressed within 28 days (or sooner if the inspector recommends immediate disconnection).

C2 — Potentially Dangerous

C2 is the most common failing code on EICRs we carry out in Petts Wood and the surrounding area. It means the condition is not immediately dangerous, but it could become dangerous under foreseeable circumstances.

Common C2 findings in BR5 properties include: absence of earthing on gas and water pipes, old consumer units with no RCD protection, circuits with degraded insulation resistance that is approaching unacceptable levels, or supplementary bonding that is missing in bathrooms.

Landlords must address C2 items within 28 days. There's no strict timeline for owner-occupiers, but addressing C2 faults is strongly recommended — they exist in the report because an electrician has assessed them as presenting a realistic risk of harm.

C3 — Improvement Recommended

A C3 is advisory only. It means the installation doesn't comply with the current edition of the wiring regulations but doesn't present a danger in its current state. Examples include circuits wired to older standards that no longer apply, or the absence of RCD protection on certain circuits that would benefit from it under modern practice.

C3 items do not make a report Unsatisfactory — a report can contain C3 observations and still pass as Satisfactory. Landlords are not legally required to address C3 findings, although doing so is generally good practice and reduces the chance of future issues.

FI — Further Investigation Required

Sometimes an EICR will include an FI code. This means something couldn't be assessed during the inspection — perhaps a section of wiring that was concealed and inaccessible, or a test result that was inconclusive. An FI isn't a pass or fail — it's a flag that further investigation is needed before the full condition of the installation can be determined.

What Happens After an Unsatisfactory EICR?

If your report comes back Unsatisfactory (due to C1 or C2 findings), you need to have the work done and then have the affected circuits re-inspected. Once the remedials are complete, a new certificate is issued — either an updated EICR or an Electrical Installation Certificate for the work carried out.

When we carry out EICRs in Petts Wood, Orpington and the surrounding area, we give a clear verbal summary at the end of the visit and provide a fixed-price quote for any required remedials at the same time. Most customers prefer to deal with everything in one go rather than waiting and rebooking.