Insulation Test Failure, a Late Delay Claim and a Payment Certificate

Technically: IEC 60364-6 requires a minimum insulation resistance of 1 MΩ at 500 V DC for a 400/230 V installation. 0.4 MΩ is a failure, not a marginal reading. It usually means moisture, a damaged sheath, a crushed or badly terminated core, or a joint that has taken water - none of which is resolved by wishful thinking about the opening date.

What to instruct:

1. Isolate and lock off; do not energise. The feeder must not be put into service with a failed test, whatever the programme pressure.
2. Require the contractor's method statement: disconnect both ends, megger each core to earth and core-to-core, and record individual values; a single overall reading on a 4-core cable hides which core is at fault.
3. If the low reading is confined to one core, look at the terminations first - a tracking lug or damp gland is the cheapest explanation to eliminate. Then test the cable on its own with the terminations removed.
4. If drying out is proposed, require it to be documented: the method, the duration, and a re-test showing a stable value above 1 MΩ that holds for at least 24 hours. A reading that creeps upward during the test indicates moisture still present and is not an acceptance.

Contractually: your duty is to certify what conforms, not what is convenient. Energising a failed circuit risks a fire in an occupied hospital and would expose both the contractor and you personally. Put the refusal in writing, with the test sheet attached, state what is required to close it out, and record the time impact as a contractor risk unless the cause is shown to be an Employer's risk event. If the opening date is at risk, the correct route is a recovery programme and, if the Employer wants acceleration, a Variation - not a signature on a failed test.

The notice is out of time. Under the Red Book, the contractor must give notice of a claim within 28 days after he became aware, or should have become aware, of the event giving rise to it. Failure to do so means the claim is time-barred: no extension of time and no additional payment, and the Employer is discharged from all liability in connection with the event. The contractor's own admission that he notified on day 35 is therefore the decisive fact.

But the Engineer's duty does not stop at 'barred'. The correct response:

1. Acknowledge receipt in writing and state the 28-day position expressly, so the record is unambiguous.
2. Still make a determination under the contract rather than leaving the matter open. The Engineer is required to consult, then determine; an unanswered claim festers into a dispute.
3. Establish the facts even where the notice is time-barred: what caused the delay, what the critical path impact actually was (the utility connection may not even have been on the critical path if the LV works were behind), whether the Employer accepted the late connection as an Employer's risk, and whether any part of the 21 days was concurrent with the contractor's own float consumption.
4. Consider whether the Employer wants to grant relief notwithstanding the bar. That is the Employer's commercial decision, not the Engineer's, and if the Employer directs it, the mechanism is a Variation or a settlement, documented as such - never a retrospective re-characterisation of a time-barred claim as an entitlement.

What the determination should state: the event, the dates of awareness and notice, the contractual consequence of late notice, the critical path finding (with the programme analysis attached), and the resulting entitlement - here, nil for both time and money, with the reasoning set out so that it can withstand scrutiny if it goes to dispute.

Certification approach:

• Issue the certificate within the contractual period after receiving the Statement, but exclude the disputed 185 mm² feeder item (or certify it only to the extent of work actually verified) and state the exclusion and the reason on the certificate itself, referencing the failed test.
• Certify the balance of the measured work - do not use the dispute as an excuse to freeze the whole certificate. Withholding unrelated, compliant work is itself a breach of the certifying duty.
• Record the item in a schedule of open items with the close-out condition: a valid re-test above 1 MΩ, witnessed, with the test sheet signed.
• Check the arithmetic, the quantities against the drawings, and that the retention and advance-payment recovery are applied correctly - a certificate is a financial instrument and errors are hard to reverse.

Ethical dimension: the owner's project manager is asking you to certify work you know fails the specification, with the implied argument that the opening date matters more than a test reading. That is precisely the pressure the Engineer's independence exists to resist:

1. Competence and honesty: a certificate is a professional statement that the work is in accordance with the contract. Signing for a failed item makes it false.
2. Public safety: this is a hospital. A feeder at 0.4 MΩ is a fire and continuity-of-supply risk to patients who cannot be evacuated easily.
3. Impartiality: the Engineer is not the owner's agent. Refusing an improper instruction from the Employer is as much a duty as refusing an inflated claim from the Contractor; both are dealt with the same way - in writing, with reasons.

Action: reply in writing to the project manager, copying the file, setting out the technical basis, the close-out route and the programme implications, and offer a witnessed re-test within 24 hours of the contractor being ready. If the instruction to certify is repeated, escalate formally and record that you were instructed and declined.