According to OSHA’s 29 CFR 1910.333 standard, “Conductors and parts of electric equipment that have been deenergized but have not been locked out or tagged … shall be treated as energized parts.”
Even below 240V, arc flashes can occur.
The clothes you wear under your PPE are equally important. Molten metal –or the arc flash itself– may get beneath your PPE, only for a moment, and ignite your undergarments.