You direct the electrician to take quarterly insulation resistance reading of the ship's critical motors. What additional directions would you give to ensure accurate readings are taken that will allow for the logical comparison of prior and current readings?

Correct Answer: Option C — Correct the readings to a reference temperature; reference temperature should be recorded in prior readings history.

Insulation resistance is highly temperature-dependent, as resistance decreases significantly as temperature rises. IEEE 43 standards mandate correcting measured values to a reference temperature, typically 40°C, to ensure that historical data remains comparable and that insulation degradation is accurately identified rather than masked by fluctuating ambient or operating temperatures.