What percentage of its nameplate voltage must equipment be engineered to operate properly at?

Equipment should be engineered to operate properly at 85% of its nameplate voltage. This standard is important for ensuring that devices function reliably even under conditions where voltage might drop due to various factors, such as long wire runs or overloads. Operating at this percentage allows for a buffer that helps to avoid tripping circuits and ensures that the system maintains optimal performance and safety during fluctuations.

Designing electrical equipment to operate at 85% of the rated voltage ensures compatibility with various power supply conditions and helps mitigate issues related to under-voltage that could lead to improper operation or even damage to the equipment. Additionally, it complies with common industry standards and practices aimed at enhancing reliability and extending lifespan.