East Ham, London · EICR case study
An unsatisfactory EICR in East Ham revealed hazards across the installation
Reason for testing: The landlord arranged the EICR before a new tenant moved in.
During this East Ham inspection, we traced concerns from the service intake through the main distribution board to an under-stairs top board. The findings include undersized conductors, improvised bare copper links, questionable protective-device arrangements and insecure board mounting.
- Multiple C2 safety observations
- Separate main-board and top-board findings
- Earthing conductor checked with an adiabatic calculation
- Evidence-led notes on fire, shock and disconnection risks
Codes and remedial decisions are specific to the inspected installation and test results.
The full intake · main board · isolator
One case study, findings traced across the installation
Explore the individual observations, recorded codes and technical context in the sections below.
Undersized Main DNO Earthing: Code C2
During this inspection, the single-core copper main earthing conductor was recorded as 6.0 mm² and enclosed in PVC trunking. The case notes assess it against the stated 100 A BS 88-3 fuse data using the adiabatic equation.
Why it is dangerous: the earth may not withstand a fault
The main earthing conductor provides a path for fault current so the protective device can disconnect the supply. If it is too small for the fault energy and disconnection time, it may overheat or be damaged before the fuse operates. A compromised earthing path can leave exposed conductive parts at a dangerous voltage and increase the risk of electric shock or fire.
Recorded as C2 · Potentially Dangerous
For this installation, the recorded 6.0 mm² conductor was assessed against the stated fuse-curve point and adiabatic calculation below. On that project-specific basis, the inspector recorded C2 and the EICR outcome as unsatisfactory.
Observed size · calculated minimum · next standard size
S = I × √t ÷ k = 580 × √5 ÷ 115 ≈ 11.28 mm²Adiabatic equation using k = 115 for the stated single-core copper/PVC conductor scenario.
Calculation basis: 11.28 mm² is the calculated minimum using the stated 580 A, 5-second disconnection time and k = 115. The next standard conductor size selected in the project notes is 16 mm². Confirm the fuse curve, conductor characteristics and installation design against the inspection records before treating these figures as final.
Evidence and reference material
Inspection evidence, fuse disconnection reference and the protective-conductor k-value table.
Main Distribution Board: Multiple C2 Safety Findings
The supply entered from 100 A connector blocks after the meter through red and black 10 mm² aluminium tails to a 100 A Type AC RCD. From its load side, a 6 mm² conductor fed a rotary isolator serving the upper distribution board, while another 6 mm² conductor was looped across MCB terminals instead of a proper busbar. The inspection also recorded concerns with the shower circuit, mixed-brand devices and earthing. The findings below explain the recorded codes and why each item matters.
Reading the codes: C2 means potentially dangerous and requires urgent remedial action; C3 means improvement recommended; FI means further investigation is needed without delay. The codes here are specific to this inspection. Protective-device suitability and conductor sizing must be confirmed from the actual equipment, test results and design data.
What was found, and why it matters
Each observation has its own code, risk explanation and assessment note.
10 mm² aluminium meter tails on a 100 A supply
Potentially dangerousWhy concerning: The conductor material, cross-sectional area, installation conditions and terminations must be suitable for the prospective load and protective arrangement. Undersizing or unsuitable aluminium terminations can overheat and deteriorate. Recorded code: C2 in this inspection due to the assessed supply-conductor and termination risk. Confirm the conductor specification and service protection from site records.
100 A Type AC RCD used as the main RCD
Potentially dangerousWhy concerning: A Type AC device is suitable only where the connected loads are known not to produce residual-current waveforms that the device cannot detect correctly. Electronic loads can affect RCD performance. Recorded code: C2 for this installation based on the inspector's assessment of device suitability and the circuits supplied. Verify connected equipment, device instructions and test results; Type AC alone does not determine a code in every installation.
6 mm² conductor tapped from the RCD load side to a rotary isolator
Potentially dangerousWhy concerning: An RCD provides residual-current protection; it does not by itself provide overcurrent protection. The 6 mm² cable needs suitable overload and fault protection for its size, route and connected load. Recorded code: C2 because the sub-main protection was assessed as inadequate in this arrangement. Check the upstream fuse or protective device and its coordination with the cable.
6 mm² cable looped across MCB terminals instead of a busbar
Potentially dangerousWhy concerning: Breaker terminals and links must be used within their manufacturer's approved conductor, termination and current ratings. An improvised loop can create poor clamping, loose connections and local heating or arcing. Recorded code: C2 based on the observed improvised distribution arrangement and associated risk.
Bare copper CPCs without green-and-yellow sleeving
Improvement recommendedWhy concerning: Protective conductors should be identifiable at terminations. Missing sleeving can cause confusion during inspection or future work. Recorded code: C3 where the CPCs were otherwise secure and no immediate danger was identified. Loose, damaged or accessible conductors may require a different assessment.
6 mm² main earthing conductor from the UKPN head
Potentially dangerousWhy concerning: The conductor must withstand the thermal energy of the earth-fault current until disconnection. For the project calculation, 580 A, 5 seconds and k = 115 give a minimum of approximately 11.28 mm². A 6 mm² conductor is below that result. Recorded code: C2 on the case-specific assessment that the earthing conductor may not withstand the fault energy.
Mixed-brand MCBs and RCDs in the board
Potentially dangerousWhy concerning: The mixed devices were assessed in this inspection as an incompatible combination with the board and its busbar arrangement. A poor mechanical or electrical interface can result in insecure contact, overheating and arcing. Recorded code: C2 for the unsafe combination identified at this installation. Compatibility must be established from the exact device models and manufacturer instructions, not brand appearance alone.
6 mm² shower cable protected by a 40 A double-pole MCB
Potentially dangerousWhy concerning: The supplied BS 7671 Table 4D5 reference lists 6 mm² flat copper cable at 34 A for installation Method 100. That is below the 40 A MCB rating recorded for this circuit, so the cable may be exposed to overload current beyond its tabulated capacity and overheat. Recorded code: C2 for the cable and overcurrent-protection mismatch in this installation. The 40 A RCD is additional residual-current protection; its 40 A rating is not an overcurrent trip.
Shower circuit: cable capacity below MCB rating
The supplied Table 4D5 reference gives a 34 A current-carrying capacity for 6 mm² flat copper cable under installation Method 100. The circuit's 40 A double-pole MCB exceeds that table value. Actual capacity must also account for the cable route, grouping, ambient temperature and other applicable correction factors.
Top Distribution Board: Shock and Fire Risks
Inspection of this under-stairs board found a bare 6 mm² copper link looped across breaker terminals in place of a proper busbar, missing CPC identification and several circuit-protection questions. The board was also reportedly secured with one screw to timber framing beside a domestic escape route.
Why the combined condition matters
A bare live link, improvised terminations and insecure mounting beside timber can combine to increase the likelihood and consequences of overheating, arcing or accidental contact. The board is considered a significant fire and shock concern; the breaker findings below require device identification and test results before final conclusions about disconnection times.
Findings, codes and engineering concerns
No busbar: bare 6 mm² copper loop across the MCBs
Potentially dangerousWhat was observed: The circuit breakers were linked with a stripped, bare copper conductor instead of a suitable busbar. Why concerning: The exposed live link presents shock and short-circuit risk inside the enclosure. Irregular or insecure terminal contact can also create resistance heating, arcing and fire. Code recorded: C2 for the potentially dangerous live-link and termination arrangement recorded at this board.
CPCs without green-and-yellow identification sleeves
Improvement recommendedWhat was observed: Several copper circuit protective conductors were not sleeved at their terminations. Why concerning: Protective conductors should be readily identifiable to reduce confusion during inspection and future work. Code recorded: C3 where the conductors are secure, correctly connected and the missing identification does not create immediate danger. Loose or exposed conductors need separate risk assessment.
D32 MCB supplying the electric hob
Further investigation requiredWhat was observed: A Type D 32 A MCB supplies the hob circuit. Why concerning: A Type D device has a higher magnetic-trip threshold than Type B or C and may need a higher fault current to disconnect quickly. For a D32, the instantaneous operating range is typically 10–20 times rated current; actual disconnection depends on the device curve and measured earth-fault loop impedance. Code recorded: FI pending Zs, circuit details and manufacturer-curve verification. Type D is not automatically unsuitable in a home; if the required disconnection time cannot be met, the inspector should assess and code the defect, potentially C2.
Unmarked 32 A MCB with an older flat-head terminal screw
Further investigation requiredWhat was observed: The device appears old and does not show a clear B, C or D trip-curve marking in the photograph. Why concerning: A flat-head screw can suggest an older design, but appearance alone cannot establish the device's age, standard, condition or trip characteristic. Without an identifiable model or curve, its performance cannot be confirmed from the marking shown. Code recorded: FI pending identification of the device, its operating characteristics and measured Zs. For a relevant TN 230 V final circuit up to 32 A, verify the applicable 0.4-second disconnection requirement; if compliance cannot be demonstrated, assess and code the defect.
Type 2 32 A breaker supplying the shed
Further investigation requiredWhat was observed: A breaker marked Type 2 32 A supplies the outbuilding circuit. Why concerning: Its exact standard, trip curve, condition and suitability for the cable and shed circuit need confirming. Outdoor and outbuilding circuits may also require suitable additional protection and verified disconnection at the furthest point. Code recorded: FI pending device identification, cable-route checks, Zs and test results. If the protective arrangement fails the applicable requirements, the inspector should assign the appropriate code, potentially C2.
Board reportedly fixed with one screw beneath timber stairs
Potentially dangerousWhat was observed: The enclosure was reportedly held to angled timber framing by a single screw. Why concerning: Insecure equipment can move and strain conductors or loosen terminations. Its position beside combustible timber and on an escape route increases the potential consequences if an electrical fire occurs. Code recorded: C2 for the insecure installation and associated risk as recorded. Under-stairs location alone does not automatically determine the EICR code; the actual enclosure, mounting and fire precautions must be assessed.
Disconnection-time note: The 0.4-second limit applies to relevant TN final circuits under the applicable BS 7671 conditions; other earthing arrangements can have different disconnection-time requirements. Confirm the supply type, circuit classification, protective-device data and measured test results before drawing a conclusion.
East Ham EICR · Customer outcome
Unsatisfactory report issued. Findings explained. Remedial quote sent.
The customer received an unsatisfactory Electrical Installation Condition Report. We explained the observations in clear language, outlining the potential shock and fire risks and why the installation needed remedial attention. A quote for the recommended remedial work was then provided.
- 1Report: the inspection findings and EICR outcome were documented.
- 2Explanation: each safety observation was discussed in plain English.
- 3Next steps: a remedial quote was sent for the work identified.
Written and technically reviewed by
Shashi Pal
Director and Qualified Supervisor, Eco Tech Electrical Contractors Ltd T/A Property Cert Experts.
- Position:
- NICEIC Approved QS
- Qualification:
- JIB Gold Card
- Professional membership:
- Associate Member, IFSM (8946)
Standards and case records
- Electrical inspection: the EICR assessment refers to BS 7671 and the edition and amendments applicable to the inspection.
- East Ham property: the observations and photographs relate to the intake, main distribution board, top board and circuits inspected at this property only.
- Customer outcome: an unsatisfactory report was issued, the observations were explained to the customer, and a remedial-work quotation was provided.
- Records: the EICR, photographs, test readings and quotation are the primary records for the findings described here.
About this failed-EICR case study
The C2, C3 and FI observations describe the condition and test evidence recorded during this particular inspection. They are not a general diagnosis of other properties. An EICR outcome depends on the full inspection, measured results, supply arrangement, protective-device characteristics, cable route and applicable requirements.
Current-carrying-capacity and adiabatic calculations shown in the case study depend on stated assumptions, including conductor type, installation method, protective-device data and disconnection time. They are included to explain the reasoning for this installation, not as a design specification for another property. Final remedial decisions and conductor sizes must be confirmed by a competent person from the site conditions and project records.
The customer was sent a remedial quotation. This case study does not state that the quoted remedial work was accepted, completed, tested or certified. Any third-party network equipment or work outside the agreed scope remains subject to the relevant network operator and permissions.
