EICR observation codes explained

A C1 code indicates that there is an immediate danger of injury to persons or livestock. This is the most serious classification and requires immediate action. Appendix 6 is explicit: wherever practicable, items classified as C1 are to be made safe on discovery. Where that is not possible, the owner or user is to be given written notification as a matter of urgency.

C1 observations are relatively rare on well-maintained installations, but when they occur, they represent genuine dangers that could cause electric shock, burns or fire. Document the danger clearly, notify the responsible person in writing, and record on the report that they have been informed.

C1 examples

• Exposed live parts — live conductors accessible to touch, such as a damaged socket outlet with exposed terminals, or a missing blanking plate on a consumer unit revealing live busbars.
• Absent earthing — the main earthing conductor is disconnected or missing entirely, leaving the entire installation without an earth path. Any earth fault would not be cleared by the protective devices.
• Severely damaged distribution board — a consumer unit with fire damage, melted components, or structural failure that exposes live conductors or compromises the enclosure.
• Overloaded circuits with visible damage — cables showing signs of overheating (discoloured insulation, burnt smell), combined with undersized or missing protection, presenting an immediate fire risk.
• Metalwork at a dangerous potential — extraneous-conductive-parts (such as metal pipework or structural steelwork) found to be live to touch due to a wiring fault or absent bonding.

A C2 code indicates that whilst there may not be an immediate danger at the time of the inspection, a risk of injury could arise under foreseeable conditions. The defect requires urgent remedial action to prevent it becoming dangerous. C2 is the most commonly debated code because it turns on a professional judgement about how likely the danger is to materialise.

The distinction between C2 and C1 is immediacy. A C1 is dangerous right now — someone could be injured at this moment. A C2 is not immediately dangerous but could become so. Missing RCD protection on a socket circuit is the textbook case: the circuit may be working perfectly, but if an earth fault occurs there is no RCD to clear it quickly, and injury could result.

C2 examples

• Inadequate main protective bonding — bonding conductors to water and gas services missing, undersized, or not connected as near as practicable to the point of entry (Reg 544.1.2). Under a fault condition this could result in a dangerous potential difference between services.
• Missing RCD protection — socket-outlets with a rated current not exceeding 32 A without 30 mA RCD protection, where Reg 411.3.3 requires it. The documented risk assessment exception is not available for a dwelling.
• Undersized cables — circuit cables with a current-carrying capacity lower than the rating of the protective device, meaning the cable could overheat before the device operates.
• Lack of selectivity — protective devices coordinated such that a fault on one circuit operates an upstream device, disconnecting circuits that should have stayed live, including potentially safety services. BS 7671 calls this selectivity; discrimination is the older term for the same thing (Section 536.4).
• Zs exceeding the maximum permitted value — the measured earth fault loop impedance exceeds the value tabulated for the protective device in Tables 41.2 to 41.5, so the device may not disconnect within the time required by Reg 411.3.2.2 during an earth fault.

A C3 code indicates that a part of the installation does not comply with the current edition of BS 7671 but is not considered dangerous. These are typically features that were acceptable under the regulations in force when the installation was carried out, but do not meet BS 7671:2018+A4:2026. The inspector recommends improvement while acknowledging there is no immediate safety risk.

C3 observations do not make the EICR Unsatisfactory. Appendix 6 states plainly that a C3 recommendation is advisory only and does not affect the overall assessment of the report. A report carrying only C3 observations is Satisfactory: the installation is safe for continued use even though improvements would bring it closer to the current standard.

Property owners often misread “improvement recommended” as work they are obliged to do. It is the inspector’s job to explain that C3 items are advisory, that the installation remains safe, and that the improvements are still worth considering — particularly if other electrical work is planned.

C3 examples

• Domestic lighting circuits with no RCD — Reg 411.3.4, new at A4:2026, requires 30 mA RCD protection for AC final circuits supplying luminaires within domestic premises. On an existing installation with no aggravating factors this is typically C3, not C2.
• Label deficiencies — circuit labels on the distribution board that are faded, incomplete, or do not match the actual circuit arrangement. Missing “Safety Electrical Connection — Do Not Remove” notices at bonding connections fall here too (Reg 514.13.1).
• Accessibility issues — the consumer unit is behind stored items or at an awkward height. Reg 132.15.201 requires effective means, suitably placed for ready operation, to cut off all voltage.
• Older wiring colours not re-identified — red/black conductors from the previous standard left unmarked where they meet harmonised brown/blue. Not dangerous in itself, but Reg 514.3.1 requires cores to be identifiable, and sleeving removes the ambiguity for whoever works on it next.
• Absent RCD on a circuit where it is only recommended — for example an AFDD omitted on a socket-outlet circuit in premises where Reg 421.1.7 recommends rather than requires one. Where the premises is a Higher Risk Residential Building, HMO, purpose-built student accommodation or care home, the same omission is a departure from a requirement and warrants a harder look.

FI is recorded where the inspection and testing has identified a potential issue for which you cannot determine a classification code until further investigation has taken place — usually because of the extent and limitations agreed for the inspection. It is not a severity rating like C1, C2 and C3. It is an honest statement that something needs looking at before it can be coded.

Because FI is not a severity rating, it sits in the advisory block of Section K alongside C3 and does not, on its own, make the report Unsatisfactory. That surprises a lot of inspectors, and some scheme providers apply a stricter house rule — check yours. What FI does do is create an obligation to investigate: once the investigation is complete, the issue gets its proper code, and if that turns out to be a C1 or C2 the assessment changes. In the private rented sector, an FI also triggers the landlord’s 28-day duty to carry out further investigative work.

FI must always be accompanied by a clear explanation of why further investigation is needed and what work is required. “Further investigation required” on its own is poor practice and will be challenged by scheme auditors and clients alike. Say what you could not access or test, why, and what specific investigation you recommend.

FI examples

• Inaccessible wiring — cables concealed in walls, floors or ceilings that cannot be inspected or tested without invasive work. For example, cables routed through a ceiling void are suspected to be in contact with thermal insulation (Reg 523.9) but the void cannot be accessed to verify.
• Buried cables of unknown route — cables entering or leaving an accessory plate that disappear into a solid wall or floor, whose route and condition cannot be determined without opening up the structure.
• Suspected damage behind plasterwork — signs of previous water ingress or discolouration around an accessory suggesting possible damage to concealed wiring, where the extent cannot be established without removing plaster.
• Inconsistent test results — readings that do not match expected values with no cause identifiable on the day. For example, an unusually high R1+R2 on a circuit that may indicate a loose connection at a point that could not be accessed during the visit.
• Locked or occupied areas — parts of the installation in rooms that were locked or in use during the inspection. State which areas, and what testing is required when access is available.