I am sorry, but the documents provided do not contain specific information about arc flash boundary at 480V. However, I can provide some general information regarding electrical safety.

To ensure electrical safety at 480V, consider the following:

• Insulation and Guarding: Ensure that conductors are properly insulated and guarded to prevent accidental contact [1].
• Overcurrent Protection: Protect circuits and equipment from overcurrent in accordance with their ability to safely conduct current [2].
• Personal Protective Equipment (PPE): Use appropriate PPE, such as rubber insulating gloves, and flame-resistant clothing, especially when incident energy exceeds 2.0 cal/cm2 [3].
• Minimum Approach Distances: Maintain safe approach distances from exposed energized parts [1].
• Grounding: Ground electrical systems to limit voltage to ground on ungrounded conductors [4].
• Qualified Persons: Ensure that only qualified persons perform testing work on electrical circuits or equipment [5].

For detailed arc flash boundary calculations, consult IEEE Std 1584b-2011 or other calculation methods [6].