Classification codes on an office EICR
An EICR of a two-storey office: TN-S, Ze 0.21 Ω, 100 A main switch, one main board in a locked riser and seven sub-boards. You record the following. (1) The 2.5 mm² T&E to the first-floor kitchen ring runs diagonally through a plasterboard wall at about 30 mm depth, with no RCD and no earthed metallic covering. (2) The 30 mA RCD protecting the ground-floor socket circuits operates at 5×IΔn in 14 ms but does not operate at 1×IΔn on two attempts; its test button works. (3) A 45 mm knockout is open in the main board cover in the locked riser, exposing part of the neutral bar. (4) In the server room one leg of a ring final was found disconnected in a socket back box; the socket still works. (5) Circuit charts are missing from three of the seven sub-boards. (6) A 4 mm² submain disappears into a concrete floor with no visible route and no drawing.
1. Assign and justify a classification code for each of the six observations.
Read the worked answer
(1) C2 - not in a safe zone, less than 50 mm deep, no RCD and no earthed metallic covering. A diagonal route through plasterboard is exactly where someone will drive a fixing; the wall can become live with no additional protection. (C3 would only be arguable if the run were in a recognised safe zone and the risk of penetration were low.)
(2) C2 - the device does not operate at its rated residual operating current. The test button proves the mechanism moves, not that it trips at 30 mA, so the test button is not evidence of compliance. Additional protection for the socket circuits is lost.
(3) C2, not C1 - live parts are accessible, but only to someone with a key to the riser. C1 requires danger present with a realistic prospect of injury to persons now; in a locked riser the exposure is limited. If the same hole were in a corridor-accessible board it would be C1.
(4) C2 - the ring is broken and the remaining leg carries the whole load of the circuit, so the cable can be overloaded; there is also a disconnected conductor end that may be live inside the back box.
(5) C3 - no immediate danger, but identification and the schedule of circuits are part of what makes the installation safe to work on and to isolate. Improvement recommended.
(6) FI - this is not yet a defect: it is an observation that cannot be resolved with the information available. Further investigation is required, and the report should say what that investigation is.
2. What is the overall assessment, and what must you do before leaving site?
Read the worked answer
Overall assessment: unsatisfactory. Any C1 or C2 makes the report unsatisfactory as a matter of fact. The C2s here (RCD not operating, damaged cable in a wall, open ring, exposed live parts) all represent potential danger.
Before leaving site
- Tell the duty holder in writing without delay of the danger and what must be done about it, in plain language, separate from the report - you cannot wait for the report to be typed up.
- Recommend immediate action on the RCD and on the broken ring, and short-term action on the wall cable and the open knockout.
- Leave a durable warning at the board for the open knockout if it cannot be closed at once, and record that you did so.
- Agree access and a programme for the FI on the submain; the report is not closed out until it is investigated or the limitation is clearly stated.
What 'unsatisfactory' is not It is not a statement that the building must be evacuated. It is a statement about the condition of the installation and the prioritisation of the remedial work, and the report should make that distinction clear so the client acts on the right items first.
3. The client asks you to downgrade the RCD observation to C3 because 'the board is being replaced next year anyway'. How do you handle it?
Read the worked answer
- The code reflects the condition found and the risk it presents, not the client's programme. A device that does not trip at 30 mA is C2 today whatever happens next year.
- What the client's plans legitimately affect is the recommendation: it is entirely reasonable to record that the whole board is due for replacement in 12 months and to phrase the remedial recommendation accordingly, provided the immediate risk is dealt with - in practice, replace or isolate the defective device now.
- If the client wants the finding recorded differently, the answer is no, and the reason is straightforward: if someone is injured before the board is replaced, the report is the evidence of what you found and how you graded it.
- Nothing stops the client seeking a second opinion or engaging someone else. It does not change what you write.
The distinction to hold on to is between the code (a professional judgement about condition and risk, which is not negotiable) and the recommendation (practical advice about how and when to remedy, which is).