Which type of system is mandated to be grounded?

• A. DC systems under 1,000V
• B. AC systems over 1,000V that supply mobile or portable equipment
• C. AC systems at any voltage
• D. Residential systems

Answer: (B)

The correct response identifies that AC systems over 1,000V that supply mobile or portable equipment are specifically mandated to be grounded. This requirement stems from safety standards aimed at reducing the risk of electric shock and ensuring that equipment operates safely in environments where mobility is a factor. Grounding these systems helps to provide a pathway for fault currents, which enhances overall safety and stability, particularly in mobile or portable applications where users may be more exposed to electrical hazards.

In the context of electrical installations, grounding plays a critical role in protecting both personnel and equipment from electrical faults. It ensures that in the event of an overvoltage or fault situation, the electric current can safely dissipate into the ground, minimizing risk to users.

Other options address different types of electrical systems, but they do not carry the same grounding mandates as specified for AC systems over 1,000V used with portable equipment. Understanding the specific requirements for these various systems is crucial for ensuring compliance with electrical safety standards and for designing safe electrical systems in commercial and industrial settings.