Which system is not required to be grounded even if it operates in the specified voltage range?

The reasoning behind the answer lies in the nature of industry-specific systems and their grounding requirements. Systems used for industrial heating processes often do not have a mandatory requirement for grounding if they are designed to operate safely within certain parameters. These systems may utilize methods such as insulation and isolation to ensure safety while minimizing the risk of electrical hazards.

In contrast, systems that supply power to robotic devices or those dedicated to lighting commercial spaces have intrinsic grounding requirements due to the potential risks associated with their operation. Additionally, residential power supply systems have strict grounding mandates to protect both equipment and individuals from electrical faults. The focus on the industrial heating processes in this context aligns with the understanding that specific applications may not necessitate grounding under certain conditions outlined by electrical codes and standards.