What is the inspector's duty of care upon finding a C1 defect?

Under Electrical Safety First BPG 4 and IET Guidance Note 3, discovering a C1 defect requires an immediate four-stage response: (1) Notify the person ordering the work or site duty holder orally immediately; (2) Isolate or make safe the dangerous circuit before leaving site (with permission); (3) Issue a formal written Danger Notification on site before departure; and (4) Record Code C1 on the EICR schedule, making the report Unsatisfactory.

Does an FI (Further Investigation) code make an EICR Unsatisfactory?

Under BS 7671:2018+A2:2022 (current alongside A3/A4 until 15 October 2026), IET Guidance Note 3, and ESF BPG 4, any FI code automatically results in an overall Unsatisfactory assessment because safety cannot be confirmed. While the Amendment 4 model certificate notes advisory treatment in Section D, landlords under the Electrical Safety Standards in the Private Rented Sector (England) Regulations 2020 remain legally obligated to complete the further investigation within 28 days.

EICR Coding Explained: C1, C2, C3 & FI Decision Framework

Electrical Installation Condition Reports (EICRs) are among the most scrutinized and contentious documents in the UK electrical industry. Inconsistent classification of defects creates client disputes, landlord compliance failures, and legal liability. This framework aligns defect coding with Electrical Safety First Best Practice Guide 4 (BPG 4), IET Guidance Note 3 (GN3), and BS 7671.

The Purpose of an EICR

An EICR is an engineering assessment of an existing electrical installation against the safety intent of current standards (BS 7671). Crucially, an EICR is not a snagging list, nor is it an order to retrospectively upgrade older installations that were fully compliant with earlier editions and remain safe in service.

The primary criterion governing every observation is: Does this condition present a realistic risk of electric shock, fire, or burns under normal operation or foreseeable fault conditions?

Code C1: Danger Present (Immediate Action Required)

Definition: Risk of injury is immediate. Persons using the installation are at direct risk of electric shock, burns, or fire without another fault occurring.

Mandatory C1 Duty of Care Sequence (BPG 4 & GN3):

Immediate Oral Notification: Inform the person ordering the work, duty holder, or site occupier immediately upon discovering the hazard.
Isolate or Make Safe Before Leaving: With client permission, isolate the dangerous circuit or component, or apply immediate temporary guarding per the Health and Safety at Work etc. Act 1974 (HSWA) and EAWR 1989 Regulations 4, 12, and 14.
Issue Formal Written Danger Notification: Hand over a formal written 'Danger Notification' document on site before departure, detailing the circuit isolated and the risk.
Record C1 on the EICR: The condition is formally documented on the report schedule, guaranteeing an overall Unsatisfactory assessment.

Typical C1 Examples:

Exposed live conductors accessible to touch (e.g. broken accessories, open enclosures, missing blanks on consumer units allowing direct finger contact).
Conductive accessible parts that are live due to an active, uncleared earth fault or reversed supply polarity.
Severe thermal damage with active carbonisation and exposed bare live copper.

Code C2: Potentially Dangerous (Urgent Remedial Action)

Definition: The observed defect does not present immediate danger now, but could lead to danger in the event of a secondary fault or foreseeable event.

Outcome: A single C2 observation automatically mandates an overall Unsatisfactory assessment on Section D of the report.

Typical C2 Examples:

Absence of a reliable earthing facility or absence of main protective bonding to incoming extraneous conductive parts (water/gas services) under Regulation 411.3.1.2.
Earth fault loop impedance (Z_s) exceeding maximum permitted disconnection thresholds where no supplementary RCD protection provides automatic disconnection under Regulation 411.4.5.
Lack of 30 mA RCD protection on socket-outlets that can reasonably be expected to supply portable equipment outdoors (Regulation 411.3.3).
Undersized protective conductors unable to satisfy thermal constraints under the adiabatic equation (Regulation 543.1.3).

Code C3: Improvement Recommended

Definition: Non-compliance with the current edition of BS 7671 that does not present immediate or potential danger. It highlights areas where safety could be enhanced.

Outcome: C3 observations alone do not make the report Unsatisfactory. An installation with multiple C3 codes and zero C1/C2/FI codes is officially Satisfactory.

Typical C3 Examples:

Absence of RCD protection on standard indoor lighting or socket circuits installed to an earlier edition, where cables are buried > 50 mm or mechanically protected and not supplying outdoor portable equipment.
Absence of Surge Protection Devices (SPDs) or Arc Fault Detection Devices (AFDDs) in an existing installation that predates mandatory requirements.
Presence of Type AC RCDs on domestic circuits feeding electronic appliances, provided no manufacturer specifies Type A/F/B and no blinding DC saturation is present.
Absence of circuit directory charts, warning notices, or periodic inspection labels.

Code FI: Further Investigation Required (The Transition Reality)

Definition: The inspector observes evidence indicating an underlying safety hazard that cannot be fully verified within the agreed extent and limitations of the inspection.

The Dual-Regime Framework & Landlord Law:

Under BS 7671:2018+A2:2022 (Current until withdrawn 15 Oct 2026): The model form in Appendix 6 dictates that an FI code produces an overall Unsatisfactory assessment, because safety cannot be confirmed.
Under BS 7671:2018+A4:2026 (Model Form Notes): Appendix 6 notes state that only C1 and C2 observations automatically result in an Unsatisfactory report, with FI treated as further investigation advised.
Statutory Landlord Compliance: Under the Electrical Safety Standards in the Private Rented Sector (England) Regulations 2020, a landlord is legally required to carry out any further investigative work identified on the report within 28 days and obtain written confirmation of compliance. An FI code cannot be ignored or treated as a cosmetic C3.
Strict Prohibition: FI must never be used as a substitute for areas excluded under agreed limitations. Inaccessible areas (such as locked rooms or un-lifted floors) belong in the 'Extent and Limitations' section, not as FI codes.

Controversial Coding Scenarios: Industry Reference Table

Inspection Scenario	Classification Code	Regulatory / BPG 4 Rationale
Socket-outlet likely to feed outdoor equipment with no RCD	Code C2	High risk of electric shock with handheld equipment in outdoor conditions (Reg 411.3.3 / BPG 4).
Standard indoor socket-outlets with no RCD (not likely to feed outdoors)	Code C3	Installed to an earlier edition; absence of additional protection is an improvement recommendation (BPG 4).
Absence of Surge Protection Device (SPD) in existing board	Code C3	Non-compliance with Reg 443.4.1 does not present immediate or potential danger (unless critical life-support).
Type AC RCD on standard domestic electronic loads	Code C3	Improvement recommended under Reg 531.3.3. Upgrade to C2 only if specific connected equipment (e.g. EV charger) blinds the RCD.
No supplementary bonding in bathroom, but 30 mA RCD present, ADS met, and main bonding verified	NO CODE (Compliant)	Regulation 701.415.2 explicitly permits omission of supplementary bonding when all three criteria are satisfied.