EICR Codes Explained: What Do C1, C2, C3 and FI Mean?

Receiving your EICR can be confusing if you do not know what the codes mean. A report full of C1s, C2s and FIs can look alarming — but understanding what each code actually means will help you respond appropriately and avoid unnecessary panic or expense.

C1 — Danger Present

A C1 observation means there is an immediate danger present in the electrical installation. This is the most serious code and requires immediate action. In some cases, the electrician may make the installation safe before leaving the property. C1 observations might include exposed live conductors, missing earth connections on metal parts, or a severely overloaded circuit.

C2 — Potentially Dangerous

A C2 observation means the installation is potentially dangerous — not an immediate risk, but one that could become dangerous under certain conditions. C2 observations must be rectified urgently. For landlords, this means within 28 days of the EICR being issued. Examples include inadequate earthing, absence of RCD protection, or deteriorated wiring.

C3 — Improvement Recommended

A C3 observation is not a failure — it is a recommendation for improvement. A property can still receive a satisfactory EICR with C3 observations present. However, C3 items should be addressed at the next convenient opportunity. Common C3 observations include older wiring that still meets minimum standards but would benefit from upgrading, or the absence of surge protection devices.

FI — Further Investigation Required

An FI observation means the electrician was unable to fully assess part of the installation and further investigation is needed. This might be because access was restricted, or because a fault was suspected but could not be confirmed without additional testing. FI observations must be investigated before the EICR can be finalised.

Satisfactory vs Unsatisfactory EICR

An EICR is classified as Satisfactory if it contains only C3 observations (or none at all). It is classified as Unsatisfactory if it contains any C1, C2 or FI observations. For landlords, an unsatisfactory EICR means remedial works must be completed within 28 days.

What Happens After Remedial Works?

Once all C1 and C2 observations have been rectified, the electrician issues an Electrical Installation Certificate (EIC) or Minor Works Certificate for the remedial works. This, combined with the original EICR, demonstrates that the installation is now satisfactory. DDF Electrical handles both the EICR and all remedial works across Nottinghamshire.