Which situation would require immediate attention while working with electricity?

When working with electricity, detecting unusual sounds from equipment is a situation that requires immediate attention. Unusual sounds can indicate potential problems such as overheating, short circuits, or mechanical failures within the equipment. These issues could escalate into hazardous situations, including electrical fires or equipment damage, if not addressed promptly.

In contrast, while seeing a plumbed pipe might be something to take note of, it does not typically pose an immediate risk in an electrical context. Noticing a light bulb flicker can be annoying but may not necessarily indicate a critical issue that requires urgent action. A lost tool, while it may disrupt workflow, does not present an immediate danger in the same way that unusual sounds can signal a fault that needs to be rectified to ensure safety and proper operation of electrical systems.