Question 1

During your oral exam you are asked: what precautions should be taken before working on or isolating any electrical equipment, even equipment believed to be switched off?

Accepted Answer

Follow a safe isolation procedure: identify the correct circuit, isolate it at the source, lock off and tag the isolation point to prevent inadvertent re-energisation, and then prove the circuit is dead using a tested voltage indicator (testing the indicator on a known live source before and after use) — never rely solely on a switch position, indicator light, or the assumption that a circuit is dead without proving it A switch position or indicator light can be misleading due to wiring errors, mechanical faults in the switch itself, or the circuit being fed from more than one source (a particular risk on vessels with multiple generators, shore power, and battery systems), making the "prove dead" step using a tested voltage indicator the only reliable confirmation. Lock-off/tag-out procedures prevent another person from inadvertently re-energising the circuit while work is in progress — a scenario that has caused serious injuries when isolation was assumed but not physically secured — and capacitors in equipment such as VFDs or power factor correction units can retain dangerous charge even after the supply is isolated, requiring specific discharge procedures before work begins.

Question 2

You're draining a thermal oil system that was running normally a short time ago. Before opening the drain point, what should you confirm?

Accepted Answer

That the system has cooled and depressurised, and you are positioned clear of the drain point's discharge path On the dredger MV Amazone, two crew members draining a thermal oil system after months of contamination were sprayed with hot oil, suffering severe burns. The investigation found company procedures lacked clear instructions for safe drainage — confirming the system has cooled and depressurised, and standing clear of the discharge path, are essential before opening any drain point on a hot oil system.

Question 3

A thermal oil system has been contaminated and needs draining for cleaning. The written procedure tells you to open the drain valve but doesn't specify a cooling-down period or PPE. What should you do?

Accepted Answer

Treat the gap as a hazard in its own right: apply a suitable cooling/depressurising period and full PPE before proceeding, and raise the procedure gap with the Chief Engineer The FEBIMA investigation into the MV Amazone incident found that although the crew followed company procedures, those procedures lacked clear instructions for safely draining a thermal oil system. A procedure that's silent on cooling time and PPE for a hazardous task is a gap to be closed before the job starts — not a green light to skip those precautions.