EICR Codes Explained — C1, C2, C3 and FI Checker

An Electrical Installation Condition Report (EICR) records the condition of an existing electrical installation. Every defect or departure from the current edition of BS 7671 that the inspector observes is given a classification code that tells the person ordering the report how serious it is and what needs to happen next.

There are four codes:

• C1 — Danger present. Risk of injury exists at the time of the inspection. Immediate remedial action is required. The inspector should tell the duty holder straight away and, wherever practicable, make the danger safe before leaving site.
• C2 — Potentially dangerous. The defect is not causing harm during normal use right now, but a fault or a foreseeable event could make it dangerous. Urgent remedial action is required.
• C3 — Improvement recommended. The installation does not meet current standards, but there is no danger as found. Improvement would enhance safety; it is not compulsory.
• FI — Further investigation required. Something was found that suggests a safety issue, but the inspection could not confirm it. Investigation is required without delay.

A crucial point that catches out landlords and homeowners: the codes describe risk, not cost. A C2 can be a five-minute fix, and a C3 can be a full rewire recommendation. The code tells you how urgent the work is — not how big the bill will be.

C1 is reserved for defects where someone could be injured by the installation as it stands — usually because live parts are accessible to touch without tools. Typical observations most inspectors would code C1 include:

• A socket outlet with a cracked faceplate exposing live terminals that a finger can reach.
• Exposed live conductors in a junction box with no cover.
• A missing blank in the consumer unit leaving the live busbar accessible.
• A damaged shower pull-cord switch with live parts accessible through the broken casing — worse still because bathroom users are wet.
• A cracked service cut-out with live terminals visible, which also needs reporting to the distribution network operator.

When a C1 is found, the inspector should inform the duty holder immediately — not just record it in the report — and make the danger safe or isolate the affected part before leaving, where possible. A dangerous condition notification is often issued on the spot.

C2 is the most common serious code on domestic EICRs. The installation works normally today, but under fault conditions — an appliance fault, a damaged cable, a broken supply neutral — the defect would allow danger to arise. Observations most inspectors code C2 include:

• No main protective bonding to incoming gas or water pipework.
• An RCD that fails to trip within the required time when tested at its rated residual current.
• An undersized main earthing conductor that may not carry fault current safely.
• Reversed polarity at a socket outlet.
• Socket outlets without 30mA RCD protection on an installation recent enough that the protection should have been designed in.
• An electric shower circuit without RCD protection.
• Ordinary twin-and-earth cable buried in a garden without mechanical protection.

The common thread: nothing is touchable or arcing right now, but one foreseeable event separates the current state from a shock or fire. That is why C2 requires urgent remedial action and makes the report unsatisfactory.

C3 covers departures from the current standard that do not present danger as found. Installations are inspected against today's edition of BS 7671, but an installation built correctly to an earlier edition is not automatically dangerous. Typical C3 observations include:

• A plastic consumer unit in good condition (current standards call for a non-combustible enclosure in domestic premises).
• No RCD protection for socket outlets on an installation that predates the requirement, otherwise in good condition.
• Rewireable fuses in good condition.
• Unsleeved earth conductors in switch and socket back boxes.
• Missing circuit labels, warning notices or the RCD test notice.
• Cables in a loft unsupported, resting on the ceiling but undamaged.

C3 items are recommendations, not requirements. A report containing only C3 observations is still satisfactory — though a long list of C3s on an ageing installation is often the honest signal that a rewire is approaching.

FI is not a defect code — it is an honesty code. It means the inspector found something that suggests a safety issue but could not confirm it within the agreed extent and limitations of the inspection. Common examples:

• Scorch marks around an accessory where the cause — appliance, loose termination, or overload — cannot be identified without opening up.
• Ring final circuit continuity that cannot be confirmed, suggesting a possible broken ring.
• A borrowed neutral between lighting circuits whose extent is unknown.
• A circuit that could not be tested because it supplies critical equipment that could not be isolated.
• Unusual test results that need specialist analysis before the circuit can be declared safe or unsafe.

The key word in the definition is without delay. An FI is not a "look at it someday" note — until the investigation is complete, nobody knows whether a danger exists, which is exactly why an FI makes the overall report unsatisfactory.

The overall assessment on an EICR follows a simple rule:

• Any C1, C2 or FI → the report is unsatisfactory.
• Only C3 observations (or none) → the report is satisfactory.

An unsatisfactory report does not mean the property cannot be used — it means remedial action is needed before the installation can be considered safe for continued service. Once the C1, C2 and FI items are remedied or investigated, the remedial work is certificated (typically with a minor works certificate or a new EICR, depending on scope) and the installation can be shown to be satisfactory.

This is also why code selection matters commercially: the difference between a C2 and a C3 on the same defect is the difference between an unsatisfactory and a satisfactory report. Inspectors must code on risk, never on what the customer would prefer the outcome to be.

For privately rented homes in England, the Electrical Safety Standards in the Private Rented Sector (England) Regulations 2020 turn EICR codes into legal duties. In outline, a landlord must:

• Have the electrical installation inspected and tested at least every 5 years by a qualified and competent person.
• Give a copy of the report to existing tenants within 28 days, to new tenants before they occupy, and to the local authority within 7 days of a request.
• Where the report requires remedial work or further investigation (in practice, any C1, C2 or FI), complete that work within 28 days — or within any shorter period the report specifies, then obtain written confirmation from the electrician that it is done and supply it to the tenant and local authority within 28 days of completion.

Local authorities can serve remedial notices, arrange the work themselves and recover the cost, and impose financial penalties of up to £30,000 for breaches. Scotland and Wales have their own rental electrical safety regimes with similar intent — the 2020 Regulations described here apply to England.

Note the interaction with C3: because C3 items do not make the report unsatisfactory, they do not trigger the 28-day remedial duty. This is one more reason the C2/C3 boundary carries real weight.

Classification is the inspector's professional judgement — no lookup table replaces it, including this one. The codings in the checker above are how most inspectors would classify each observation in typical conditions, but the same defect can justify a different code depending on context. Experienced inspectors work through questions like:

• Is danger present now? Can live parts be touched without tools? Is something arcing, overheating, or exposed? If yes — C1.
• What has to happen before someone is harmed? If a single foreseeable event (an earth fault, a damaged lead, wet hands) bridges the gap — C2.
• Who uses the installation? A damaged accessory at floor level in a nursery reads differently from the same accessory in a locked plant room.
• Was it compliant when installed? A departure from today's standard on a well-maintained older installation, with no added danger, points to C3.
• Can I actually confirm the condition? If not, the honest answer is FI — never a guessed C3.

Industry best-practice guidance on coding exists precisely because two competent inspectors can disagree at the margins. What is never acceptable is changing a code under commercial pressure — the classification records risk, and the inspector who signs the report owns it.