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C1
Danger Present

Risk of injury. Immediate remedial action required.

C2
Potentially Dangerous

Urgent remedial action required to eliminate risk.

C3
Improvement Recommended

Installation does not comply with latest BS 7671 standard.

FI
Further Investigation

Potential safety issue that cannot be verified without delay.

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Code C1Consumer Unit & Panels

Exposed Live Conductors / Busbars Inside Consumer Unit

Exposed live copper busbar or terminal screws directly accessible to touch without the use of a key or tool (e.g. missing blanking plate or fractured enclosure lid).

BS 7671 Clause:Reg 416.2.1 (Basic Protection - Enclosures IP2X / IPXXB)
BPG4 Issue 5 Rationale:Immediate danger present. Direct contact with live parts creates severe risk of electric shock and fatal injury.
Remedial Action:Immediate make-safe: isolate supply or fit verified proprietary blanking module to achieve IP2X minimum.
Code C1Earthing & Bonding

Absence of Installation Main Earth Connection

Total absence of an effective earth connection to the installation (main earthing conductor severed, missing, or disconnected from main earthing terminal).

BS 7671 Clause:Reg 411.3.1.1 • Reg 542.1.2 (Main Earthing Conductor)
BPG4 Issue 5 Rationale:Immediate danger present. Metal enclosures will remain permanently live upon an earth fault without automatic disconnection.
Remedial Action:Immediately reconnect or install verified main earthing conductor and measure Ze.
Code C1Sockets & Accessories

Reverse Polarity on Incoming Supply / Single-Pole Neutral Switching

Incoming supply line and neutral reversed, or single-pole switches and protective devices connected in the neutral conductor instead of line.

BS 7671 Clause:Reg 132.14.1 • Reg 411.3.1.1 • Reg 530.3.2
BPG4 Issue 5 Rationale:Equipment remains live at 230V even when turned off by the local switch. Extreme shock hazard to users.
Remedial Action:Immediate isolation; notify DNO if supply-side or correct installation polarities immediately.
Code C1Wiring & Cables

Severely Damaged / Melted Cable with Exposed Live Copper

Cables with severely degraded, crushed, or burned sheath exposing uninsulated live conductors accessible to touch in accessible locations.

BS 7671 Clause:Reg 416.1 • Reg 522.8.1 (Insulation integrity & physical protection)
BPG4 Issue 5 Rationale:Danger present. Shock and fire hazard from exposed energized copper.
Remedial Action:Isolate circuit immediately; replace or splice damaged cable in verified compliant enclosure.
Code C2RCD & Protection

No 30mA RCD on Sockets Liable to Supply Portable Outdoor Equipment

Absence of 30mA RCD protection for socket-outlets rated up to 32A that could reasonably be expected to supply portable electrical equipment outdoors (e.g. lawnmowers, pressure washers).

BS 7671 Clause:Reg 411.3.3 (Additional protection by RCD ≤ 30mA)
BPG4 Issue 5 Rationale:Potentially dangerous. Outdoor use introduces damp ground contact, severely elevating shock risk upon cable severance.
Remedial Action:Install 30mA RCBO or RCD protection for the relevant socket circuits.
Code C2Earthing & Bonding

Measured Zs Exceeds Maximum Permissible Value (Table 41.3)

Earth fault loop impedance (Zs) exceeds the maximum permitted in BS 7671 Chapter 41 for the installed overcurrent device, with no supplementary RCD to guarantee disconnection within required time.

BS 7671 Clause:Reg 411.4.5 • Reg 411.3.2.2 • Tables 41.2–41.4
BPG4 Issue 5 Rationale:Potentially dangerous. In the event of a line-to-earth fault, the device will not operate quickly enough to prevent lethal touch voltages.
Remedial Action:Reduce loop impedance, install larger CPC, change protective device curve/rating, or provide 30mA RCD protection.
Code C2Earthing & Bonding

Missing Main Protective Bonding to Metallic Services (Gas/Water)

Metallic incoming service pipes (gas, water, oil) that are extraneous-conductive-parts enter the premises without main protective bonding conductors connected to the Main Earthing Terminal (MET).

BS 7671 Clause:Reg 411.3.1.2 • Reg 544.1.2 • Table 54.8
BPG4 Issue 5 Rationale:Potentially dangerous. Potential difference can develop between pipework and earthed metalwork during a fault, creating electric shock hazard.
Remedial Action:Install minimum 10mm² copper main protective bonding conductor to pipework within 600mm of meter/entry point.
Code C2Bathrooms & Special Locations

Standard 230V Socket Within 2.5m of Bathroom Zone 1

A standard 230V 13A socket-outlet is installed less than 2.5m horizontally from the edge of the bath or shower tray.

BS 7671 Clause:Reg 701.512.3 (Prohibition of socket-outlets in bathroom zones)
BPG4 Issue 5 Rationale:Potentially dangerous. High risk of water splashing into socket or portable appliances being used by wet persons.
Remedial Action:Remove socket-outlet or relocate beyond 2.5m from Zone 1 boundary with 30mA RCD protection.
Code C2Consumer Unit & Panels

Top Surface of Consumer Unit Open / Missing IP4X Seal

Top horizontal surface of consumer unit has unsealed cable entries or gaps larger than 1.0mm diameter, failing to satisfy IP4X / IPXXD.

BS 7671 Clause:Reg 416.2.2 (Ingress protection for top horizontal surfaces - IP4X)
BPG4 Issue 5 Rationale:Potentially dangerous. Foreign objects (screws, metal swarf, falling conductive dust) can drop onto live busbars causing violent arc faults.
Remedial Action:Install intumescent or compliant IP4X grommet strips / metal blind inserts on top entries.
Code C2Wiring & Cables

Absence of Metallic Fire-Resistant Cable Supports

Overhead or surface-mounted cables supported entirely by plastic trunking or plastic clips without metallic fire-rated fixings, posing premature collapse hazard in a fire.

BS 7671 Clause:Reg 521.10.202 (Prevention of premature collapse of wiring systems)
BPG4 Issue 5 Rationale:Potentially dangerous. Entanglement hazard to occupants and firefighters attempting building evacuation during structural fire.
Remedial Action:Retrofit metal cable ties, fire clips, or metal channel supports into masonry.
Code C2RCD & Protection

Type AC RCD Blinding on EV / VFD / Heat Pump Circuits

Type AC RCD installed on circuits supplying equipment known to generate smooth DC leakage or high frequencies (EV chargers, VFD inverters, variable heat pumps), causing magnetic core saturation and failure to trip on AC earth faults.

BS 7671 Clause:Reg 531.3.3 (Types of RCD - Selection for load equipment)
BPG4 Issue 5 Rationale:Potentially dangerous. DC leakage current blinds the Type AC toroid, disabling shock protection for all connected circuits.
Remedial Action:Upgrade to Type A, Type F, or Type B RCBO/RCD matching equipment manufacturer requirements.
Code C2Earthing & Bonding

Class I Metallic Light Fittings Without Circuit Protective Conductor (CPC)

Class I metal light switches or metallic light luminaires installed on circuits lacking an effective circuit protective conductor (CPC).

BS 7671 Clause:Reg 411.3.1.1 • Reg 410.3.3 (Automatic disconnection requires CPC)
BPG4 Issue 5 Rationale:Potentially dangerous. Metal switch plates or luminaires become live upon an internal insulation breakdown without tripping protective device.
Remedial Action:Replace accessories with Class II double-insulated units or rewire circuit with continuous CPC.
Code C3Wiring & Cables

No 30mA RCD on Concealed Cables in Walls (<50mm Depth)

Cables concealed in plaster walls at a depth of less than 50mm installed within prescribed safe zones but lacking 30mA RCD additional protection (where no other specific hazard exists).

BS 7671 Clause:Reg 522.6.202 (Cables concealed in walls or partitions)
BPG4 Issue 5 Rationale:Improvement recommended. Installation complied with older editions of BS 7671, but modern standards require 30mA RCD for nail/screw penetration protection.
Remedial Action:Upgrade circuit to 30mA RCBO or RCD protection at next consumer unit replacement.
Code C3Consumer Unit & Panels

Missing Safety Electrical Connection / Inspection Warning Labels

Absence of required statutory warning labels (e.g. "Safety Electrical Connection - Do Not Remove", Periodic Inspection Notice, or Harmonised Colour Warning Label where mixed colours exist).

BS 7671 Clause:Reg 514.12.1 • Reg 514.13.1 • Reg 514.14.1
BPG4 Issue 5 Rationale:Improvement recommended. Non-compliance with labeling requirements does not represent an immediate electrical shock danger.
Remedial Action:Affix engraved or verified self-adhesive compliant warning labels to board and bonding clamps.
Code C3Consumer Unit & Panels

Plastic Consumer Unit in Domestic Premises (Undamaged)

Plastic (combustible) consumer unit in domestic premises installed under earlier regulations, showing no thermal damage or loose terminal connections.

BS 7671 Clause:Reg 421.1.201 (Non-combustible enclosure in domestic premises)
BPG4 Issue 5 Rationale:Improvement recommended. The unit complied when installed; non-combustible steel casing is a modern safety standard improvement.
Remedial Action:Upgrade to 18th Edition Amendment 3 compliant steel metalclad consumer unit when replacing board.
Code C3RCD & Protection

Absence of Type 2 Surge Protection Device (SPD) in Consumer Unit

Consumer unit lacks a Type 2 Surge Protection Device (SPD) to protect against transient overvoltages of atmospheric origin or switching surges.

BS 7671 Clause:Reg 443.4.1 • Reg 534.4 (Protection against transient overvoltages)
BPG4 Issue 5 Rationale:Improvement recommended. Mandatory for new installations unless client has signed written disclaimer.
Remedial Action:Retrofit modular Type 2 SPD cartridge with dedicated 32A backup MCB into distribution board.
Code FIConsumer Unit & Panels

Unidentified Circuit / Redundant Unlabeled Wiring

Circuit connected to protective device without identification or labeling, disappearing into building fabric where the load and destination cannot be verified during inspection.

BS 7671 Clause:Reg 132.13 • Reg 514.8.1 (Documentation and identification of circuits)
BPG4 Issue 5 Rationale:Further investigation required. Inspector cannot confirm whether the circuit is safe or correctly coordinated with the protective device.
Remedial Action:Trace circuit conductors using tone generator, locate termination, verify loads, and label board schedule.
Code FIEarthing & Bonding

Main Bonding Conductor Disappears into Inaccessible Void

Main bonding conductor leaves main earthing terminal but connection to incoming gas/water service cannot be visually located or verified due to boxed-in ductwork or physical obstruction.

BS 7671 Clause:Reg 411.3.1.2 • Reg 544.1.2 (Main protective bonding continuity)
BPG4 Issue 5 Rationale:Further investigation required. Continuity test shows wandering readings, requiring access panels to be opened.
Remedial Action:Create inspection hatch or install accessible surface-routed bonding conductor directly to pipe entry.
Code FIRCD & Protection

Intermittent RCD Tripping / Shared Neutral Across Split-Load Boards

RCD trips spontaneously upon connecting test leads or exhibits erratic trip times, indicating borrowed neutrals across separate RCD banks or standing leakage exceeding 9mA.

BS 7671 Clause:Reg 531.3.2 • Reg 643.10 (Residual current device verification)
BPG4 Issue 5 Rationale:Further investigation required without delay. Borrowed neutrals create severe shock hazard to electricians isolating only one MCB.
Remedial Action:Perform full cross-neutral continuity checks, separate borrowed neutral feeds, or convert circuits to individual RCBOs.
Code C1Sockets & Accessories

Shattered Socket-Outlet / Broken Faceplate

Cracked or smashed socket-outlet faceplate allowing direct finger contact with 230V live terminals.

BS 7671 Clause:Reg 416.2.1 (Basic Protection - Enclosures IP2X)
BPG4 Issue 5 Rationale:Danger present. Immediate electric shock hazard upon normal touch.
Remedial Action:Isolate circuit and replace faceplate immediately.
Code C2EV Charging & Renewables

Outdoor EV Charger Connected to PME Without Open-PEN Protection

Outdoor electric vehicle charging point utilizing supply PME (TN-C-S) earth without an approved open-PEN detection device, independent earth electrode, or isolating transformer.

BS 7671 Clause:Reg 722.411.4.1 (Electric Vehicle charging - PME earthing restrictions)
BPG4 Issue 5 Rationale:Potentially dangerous. Loss of supply PEN conductor elevates vehicle chassis to lethal touch potential for person standing on true earth.
Remedial Action:Install EV charge point with integral open-PEN detection device or convert charge circuit to TT earthing.
Code C2EV Charging & Renewables

Missing DC Switch-Disconnector on Solar PV Inverter

Solar PV string inverter installed without an adjacent, load-break rated lockable DC isolator on the DC string input conductors.

BS 7671 Clause:Reg 712.536.2.2.1 • Reg 712.537.2 (Solar PV DC isolation)
BPG4 Issue 5 Rationale:Potentially dangerous. Inability to safely de-energize live DC strings (up to 1000V DC) during inverter maintenance or fire emergency.
Remedial Action:Install double-pole DC rated lockable switch-disconnector (BS EN 60947-3).
Code C2Consumer Unit & Panels

MCB Rating Exceeds Conductor Current Carrying Capacity

Circuit protective device rated higher than the derated current-carrying capacity of the cable (e.g. 32A MCB protecting 1.5mm² or 2.5mm² radial cable).

BS 7671 Clause:Reg 433.1.1 (Coordination between conductor and protective device: Ib ≤ In ≤ Iz)
BPG4 Issue 5 Rationale:Potentially dangerous. Prolonged overload will cause conductor thermal destruction and fire before MCB trips.
Remedial Action:Downgrade MCB rating to match cable current-carrying capacity.
Code C3Sockets & Accessories

No 30mA RCD on Domestic Lighting Circuits (Standard Fittings)

Domestic lighting circuits lacking 30mA RCD protection, installed when RCDs were not mandatory for domestic lighting under earlier 16th/17th edition rules.

BS 7671 Clause:Reg 411.3.4 (RCD protection for lighting in domestic premises)
BPG4 Issue 5 Rationale:Improvement recommended. BS 7671 18th Edition introduced mandatory RCD protection on all domestic lighting circuits.
Remedial Action:Upgrade lighting circuit MCB to 30mA RCBO during consumer unit modernisation.
Code C2Wiring & Cables

Ring Final Circuit Open Conductor / Broken Loop

Testing reveals an open circuit in the line, neutral, or CPC conductors of a 32A ring final circuit, effectively converting it into two overloaded radial circuits.

BS 7671 Clause:Reg 433.1.204 • Reg 643.2.1 (Ring final continuity test)
BPG4 Issue 5 Rationale:Potentially dangerous. 2.5mm² conductors can draw full 32A load on one leg, causing severe thermal cable overheating.
Remedial Action:Locate broken connection or loose terminal screw in socket and restore full ring continuity.
Code C3Earthing & Bonding

6mm² Main Protective Bonding on PME Supply (Undamaged)

Existing main protective bonding conductor to incoming gas or water is 6mm² copper instead of the current 10mm² requirement under BS 7671 Table 54.8 on a PME installation.

BS 7671 Clause:Table 54.8 • Reg 544.1.1 (Main bonding sizing for PME)
BPG4 Issue 5 Rationale:Improvement recommended (per BPG4 Item 3.1). 6mm² was permitted under earlier editions; upgrade recommended unless signs of thermal stress exist.
Remedial Action:Upgrade main bonding conductor to 10mm² copper during future electrical alteration.
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