4.2 Code C1 (Danger Present) & Code C2 (Potentially Dangerous) Criteria

Code C1: Danger Present (Immediate Action Required)

Technical Definition & Risk Criteria

Code C1 is assigned when an observed condition poses an immediate, direct threat of electric shock, electrocution, serious injury, or fire to persons or livestock using the electrical installation. Under BS 7671 Regulation 411.2 and IET Guidance Note 3, a Code C1 indicates that basic protection (protection against direct contact) has completely failed or is absent, exposing energized parts that are directly touchable without the use of a key or tool (breaching IP2X or IPXXB standard enclosure ratings).

When a C1 observation is identified, the safety of occupants is actively compromised at the moment of inspection. The inspector must act immediately to render the installation safe or isolate the affected section.

---

Classic Code C1 Examples (per BPG4 Issue 5)

1. Exposed Live Conductors: Accessible live copper conductors or terminals due to broken, cracked, or missing enclosure covers (e.g., a broken socket outlet faceplate revealing 230V live terminals, a broken light switch exposing live metalwork, or an open consumer unit busbar missing a blanking module).
2. Conductive Enclosures Energized Live: Metalwork of equipment or conductive structural parts that have become live due to a fault, combined with a missing or disconnected main protective bonding or earthing conductor.
3. Incorrect Polarity on Single-Pole Switching Devices: Single-pole switches, fuses, or circuit breakers connected in the neutral conductor instead of the line conductor, leaving equipment energized at 230V even when turned off.
4. Conductive Parts Live Under Normal Operating Conditions: Exposed conductive parts of electrical equipment that are live at hazardous voltages above 50V AC under normal operation.
5. Severe Fire Hazard Present: Active arcing, excessive charring/melting of insulation with exposed live conductors, or immediate risk of fire propagation due to gross overloading of conductors without protective device operation.

---

Inspector Action Protocol for Code C1

Discovering a Code C1 observation places an immediate duty of care upon the inspector under EAWR 1989. The inspector must follow a strict emergency protocol:

1. Immediate Notification: Verbally inform the person ordering the report (or responsible duty holder on site) immediately upon discovery.
2. Make Safe / Isolation: With the client's permission, make the item safe immediately. This may involve turning off and locking off the individual circuit breaker, removing the circuit fuse, or applying an approved safety lock and warning tag.
3. Emergency Action Written Notification: Issue an official written Electrical Danger Notification (or Emergency Action Notice) to the client before leaving the site. The notice must detail the nature of the danger, the location, and the isolation action taken.
4. Formal Recording: Record the C1 observation on the EICR, detailing the location, specific hazard, and any temporary make-safe action taken (e.g., "Circuit 3 isolated and locked off with client consent").

---

Code C2: Potentially Dangerous (Urgent Remedial Action Required)

Technical Definition & Risk Criteria

Code C2 is assigned when an observed defect is not immediately dangerous at the time of inspection, but possesses the potential to become dangerous upon the occurrence of a single fault, a change in environment, or a secondary event. Under IET GN3 and BPG4, Code C2 indicates that basic protection or fault protection (indirect contact protection) is severely compromised, meaning that a subsequent failure will lead to immediate electric shock or fire.

While immediate isolation before leaving site is not strictly mandatory for C2 items (unlike C1), urgent remedial action is required. The presence of a single C2 observation renders the overall EICR outcome UNSATISFACTORY.

---

Classic Code C2 Examples (per BPG4 Issue 5)

1. Absence of Main Earthing (MET / Supply Earth): Total absence or disconnection of the main earthing conductor to the installation (e.g., disconnected earth cable at the MET, missing supplier earth on a TN-S/PME system). If an earth fault occurs on any Class I appliance, all exposed metalwork will instantly become live at 230V.
2. Excessive Earth Fault Loop Impedance (Zs): Measured Zs at a final outlet or equipment exceeds the maximum permitted values specified in BS 7671 Tables 41.2, 41.3, or 41.4, such that automatic disconnection of supply (ADS) within the required disconnection time (0.4 s for final circuits ≤ 63A on 230V TN systems; 0.2 s for TT systems) cannot be achieved, and no RCD fallback is installed.
3. Absence of RCD Protection for High-Risk Socket-Outlets: Socket-outlets rated up to 32A that could reasonably be expected to supply mobile equipment outdoors (e.g., garden equipment, pressure washers) on a TN system lacking 30mA RCD protection.
4. Absence of RCD Protection in Bathrooms (Section 701): Circuits supplying low-voltage equipment or socket-outlets within location 701 (bathrooms/shower rooms) lacking required 30mA RCD protection under Regulation 701.411.3.3 where supplementary bonding is also absent or unverified.
5. Inadequate Short-Circuit Breaking Capacity: Circuit breakers or protective devices whose rated short-circuit capacity (Icn) is lower than the prospective fault current (Ipf) measured at their point of installation (violating Reg 434.5.1), presenting an explosion or arcing risk during a fault.
6. Exposed Basic Insulation (Not Live Conductors): Outer sheath of a twin and earth cable stripped back outside an enclosure, leaving single-insulated cores (e.g., brown/blue insulation) exposed to touch, but where no live bare copper is visible. Touch or mechanical damage to the single insulation could lead to direct contact.
7. Severe Thermal Damage without Exposed Live Parts: Heat discoloration, scorching, or localized melting on switchgear, consumer units, or accessories where live conductors remain enclosed within IP2X ratings, but thermal degradation threatens containment integrity.
8. Class I Luminaires / Light Switches Installed Without Earth (CPC): Class I (metallic) light fittings or metal switch plates connected to a lighting circuit that lacks a continuous Circuit Protective Conductor (CPC).

---

Comparison Matrix: Code C1 vs Code C2