What do the EICR codes C1, C2, C3 and FI mean?

Glossary · Testing, inspection and certificates

How the codes work

When an inspector finds something wrong during an EICR, they write it down as an observation and give it one classification code. The codes are C1, C2, C3 and FI.^{[1]Ministry of Housing, Communities and Local Government, Electrical safety standards in the private and social rented sectors: guidance} Each observation gets one code only. If more than one could apply, the most serious is used, with C1 the most serious.^{[4]Electrical Safety First, Electrical Installation Condition Reporting: Best Practice Guide 4, Issue 7}

The overall result of the report is either satisfactory or unsatisfactory. A C1 or a C2 makes it unsatisfactory.^{[2]NICEIC, Electrical Installation Condition Reports (EICRs)[5]Institution of Engineering and Technology (IET), EICR Myths (Wiring Matters, May 2021)}

The four codes

The meanings of C1, C2 and C3 are in the government’s landlord guidance and in NICEIC’s householder guidance.^{[1]Ministry of Housing, Communities and Local Government, Electrical safety standards in the private and social rented sectors: guidance[2]NICEIC, Electrical Installation Condition Reports (EICRs)} The guidance says an inspector may make any C1 hazard safe before leaving the property.^{[1]Ministry of Housing, Communities and Local Government, Electrical safety standards in the private and social rented sectors: guidance} Electrical Safety First’s Best Practice Guide 4 adds that the client should be told at once and in writing that immediate action is needed.^{[4]Electrical Safety First, Electrical Installation Condition Reporting: Best Practice Guide 4, Issue 7}

A C2 is not dangerous today but would become an immediate danger if a fault or other foreseeable event occurred.^{[4]Electrical Safety First, Electrical Installation Condition Reporting: Best Practice Guide 4, Issue 7} A C3 is a recommendation only. Landlords do not have to carry out a C3 improvement, though doing so would make the installation safer.^{[1]Ministry of Housing, Communities and Local Government, Electrical safety standards in the private and social rented sectors: guidance}

FI: check your own report

FI has changed, and the sources differ. The government landlord guidance, published in November 2025, describes FI as further investigation required without delay, and says a landlord must ensure that work is carried out.^{[1]Ministry of Housing, Communities and Local Government, Electrical safety standards in the private and social rented sectors: guidance} The IET reports that BS 7671:2018+A4:2026 separates C3 and FI from C1 and C2 so that neither makes a report unsatisfactory, and softens FI to “further investigation is advised”.^{[3]Institution of Engineering and Technology (IET), Implications of BS 7671:2018+A4:2026 on an EICRs (Wiring Matters, July 2026)} NICEIC’s householder page also says FI does not make a report unsatisfactory.^{[2]NICEIC, Electrical Installation Condition Reports (EICRs)}

For a rented home in England, treat any FI as work to be done within the landlord deadline unless your electrician and the current guidance say otherwise. Ask the inspector to explain why they used it. The IET says FI should rarely be needed, because it is used only where a potential safety issue could not be fully determined within the limits of the inspection.^{[3]Institution of Engineering and Technology (IET), Implications of BS 7671:2018+A4:2026 on an EICRs (Wiring Matters, July 2026)} Our EICR remedial work deadline page covers the time limits.

Example

Meera’s EICR for her Headingley house includes a socket outside that is likely to be used for portable equipment in the garden. It has no RCD protection. The IET says Electrical Safety First’s guide recommends a C2 for that, which means the report is unsatisfactory.^{[5]Institution of Engineering and Technology (IET), EICR Myths (Wiring Matters, May 2021)} The same report notes a plastic consumer unit. The IET says that on its own it is worth a note, with no code, and a C3 is recommended only if the unit is under a wooden staircase or in the sole escape route.^{[5]Institution of Engineering and Technology (IET), EICR Myths (Wiring Matters, May 2021)}

What people get wrong

Many people read a C3 as a fail, or an FI as a fault. A C3 is advice and the report can still be satisfactory with several of them. The code reflects danger or potential danger, not whether the installation matches the newest edition of the wiring regulations.

The IET makes the same point from the other side: an installation that does not meet the current standard is not necessarily unsafe, and the inspector must use engineering judgment.^{[5]Institution of Engineering and Technology (IET), EICR Myths (Wiring Matters, May 2021)} Questions about a code are best put to the inspector who wrote it. If you want a second view, our EICR testing page explains how we report.

The bottom line

A C1 or C2 makes an EICR unsatisfactory and means work is needed. A C3 is a recommendation. FI is the code in transition, so read your own report and ask the inspector what it means in your case. Landlords in England should treat FI work as required, as current government guidance says. Our how long an EICR is valid page covers what follows an unsatisfactory report.