Question 69 CEL02 - Chief Engineer - Limited (Alt)

The Correct Answer is C **Explanation for Option C (Correct Answer):** Option C states that the infrared camera recording is taken **immediately after de-energizing and isolating** in accordance with safety procedures. Infrared thermography relies on measuring the heat signatures generated by resistive or mechanical issues while the equipment is under load (energized). If a specially designed IR window is not available, safe work practices require the enclosure door to be opened only after the equipment is de-energized and isolated (made electrically safe). To ensure that the thermal signatures (heat) generated during the energized state are still present and measurable, the recording must be taken **immediately** after isolation. Waiting too long allows the heat to dissipate, resulting in inaccurate readings that do not reflect the operating conditions. This procedure prioritizes safety (de-energizing) while maintaining accuracy (immediate measurement). **Explanation of Incorrect Options:** * **A) The infrared camera recording is taken while energized with the enclosure door open in accordance with safety procedures.** This is incorrect and highly dangerous. Opening an enclosure door while the equipment is energized exposes personnel to severe electrical hazards, including arc flash, which violates fundamental electrical safety procedures (e.g., NFPA 70E, CSA Z462). * **B) The infrared camera recording is taken before de-energizing and isolating in accordance with safety procedures.** This option simply describes the standard time frame for when the thermal data would naturally be collected (i.e., when the equipment is running). However, it does not address the core issue of obtaining the reading **safely** when an IR window is absent. Taking the reading *before* isolation still requires opening the door while energized (Option A), which is unsafe. * **D) The infrared camera recording is taken after waiting a suitable period of time after de-energizing and isolating in accordance with safety procedures.** This is incorrect because waiting a suitable period of time would allow the heat patterns (thermal signatures) to dissipate or cool down significantly. This dissipation would render the thermographic readings inaccurate, as the captured temperatures would no longer reflect the equipment's condition while it was energized and under load.