What safety features are commonly used in electronic equipment?

High voltage indicators and alarms, as well as grounds and emergency shut down buttons, are critical safety features in electronic equipment. Grounding is essential for directing excess current safely into the ground, preventing electrocution or electrical fires. Emergency shut down buttons allow for immediate disconnection of power in hazardous situations, ensuring the safety of users and protecting the equipment from damage.

While other options may offer benefits in terms of usability or protection in specific contexts, they do not provide the same level of immediate safety in potentially hazardous scenarios. For example, light indicators and automated timers enhance user experience but do not actively prevent accidents. Water-resistant casings and thermal insulation protect against environmental factors but do not address electrical safety risks. Therefore, the combination of grounding and emergency shut down buttons stands out as the appropriate answer, as they directly mitigate significant electrical hazards.