According to NEC, what is required for an output voltage higher than 50 VAC?

In accordance with the National Electrical Code (NEC), grounding requirements for secondary windings of transformers are essential for safety. When dealing with output voltages higher than 50 VAC, it is crucial to mitigate the risk of electric shock and ensure system reliability. Grounding one side of the secondary is a means to provide a reference point for the system and also serve as a safety measure.

By grounding both sides of the secondary winding, any fault conditions can be effectively managed, as it allows for the quick operation of protective devices, thereby reducing the chances of equipment damage and promoting a safer working environment. This dual grounding approach minimizes the potential for hazardous voltage conditions in case of insulation failure, contributing to overall electrical safety.

The other alternatives do not meet the NEC’s requirements for safety and practical operation under these circumstances. Grounding both sides of the secondary is vital for systems where higher voltages are present, ensuring compliance with safety regulations.