Your EICR report has come back with codes on it — but what do C1, C2, C3 and FI actually mean? We explain each classification and what action is required.

When you receive your EICR (Electrical Installation Condition Report), you'll see a series of observations listed with code classifications. These codes — C1, C2, C3 and FI — indicate the severity of each finding and what action is required. Understanding them is important whether you're a landlord, homeowner or tenant.

C1 — Danger Present

A C1 code means "Danger Present — Risk of injury. Immediate remedial action required." A C1 finding means a live electrical hazard exists in your property that poses an immediate risk of electric shock, fire or injury. When a C1 code is raised, the inspector must (where possible) make the defect safe before leaving the property — typically by isolating the affected circuit.

Common causes of C1 codes include: exposed live conductors, absent or damaged earthing, incorrect polarity on circuits, and wiring in contact with heat sources. An EICR with a C1 code will always result in an Unsatisfactory overall verdict. For landlords, this means the property must not be let until the C1 fault is rectified and a new Satisfactory EICR issued.

C2 — Potentially Dangerous

A C2 code means "Potentially Dangerous — Urgent remedial action required." C2 faults are serious defects that don't represent an immediate risk but could deteriorate into one. Under the landlord regulations, C2 faults must be rectified within 28 days of the report being issued.

Common C2 findings include: absence of RCD protection on circuits where it's required, inadequate earthing or bonding, overloaded circuits, and wiring that's deteriorated significantly due to age. Like C1, a C2 code means the EICR will be Unsatisfactory.

C3 — Improvement Recommended

A C3 code means "Improvement Recommended." Importantly, C3 codes are advisory only — they do not fail the EICR. A report can still return a Satisfactory overall verdict even with multiple C3 observations. C3 codes typically flag wiring or equipment that complied with the regulations when installed but doesn't meet current standards — for example, older single-pole switches in bathrooms, or circuits without surge protection that's now considered best practice.

While C3 observations don't require action to pass the report, they're worth addressing over time — particularly if you're a landlord looking to avoid them escalating to C2 codes by the next inspection.

FI — Further Investigation Required

FI (Further Investigation Required) is used when the inspector couldn't complete testing on part of the installation — often because access was restricted, or because test results were inconclusive. An FI code means more investigation is needed before that aspect of the installation can be confirmed as safe or unsafe. An EICR with an FI code will be Unsatisfactory until the further investigation is carried out.

Satisfactory vs Unsatisfactory: The Bottom Line

• Satisfactory: No C1 or C2 codes found. The installation is safe to use. C3 codes may be present (advisory only).
• Unsatisfactory: One or more C1, C2 or FI codes found. Remedial work is required.
• C1 and C2 = Unsatisfactory. C3 alone = Satisfactory.
• Landlords must carry out remedial works and re-test if Unsatisfactory.

We Carry Out EICR and All Remedial Works

KLIC ELECTRICAL carry out EICR inspections across East London and can complete all C1 and C2 remedial works on the same or following visit — re-testing and issuing a new Satisfactory certificate on completion. We cover the full Tower Hamlets and Docklands area.