When does a pilot lamp typically illuminate?

A pilot lamp is designed to provide a visual indication that a device, such as an oven, is operational and drawing power. It illuminates specifically when the heating element is energized, signaling that the appliance is actively heating. This is important for safety and operational reasons, as it allows users to understand when the appliance is in use and when to exercise caution.

While other options might suggest different situations, they do not specifically align with the operation of the pilot lamp. For example, the oven being preheated may involve the heating element activating, but the pilot lamp's illumination is solely tied to the moment the heating element is energized. Additionally, the food being ready or when the convection fan starts do not directly correlate to the pilot lamp's indication of power and heating status, as these events can occur without the heating element being energized.