Busways shall be permitted to be extended vertically through dry floors if totally enclosed (unventilated) where passing through and for a minimum distance of how many feet above the floor?

The correct answer is based on the National Electrical Code (NEC) requirements regarding busways. When busways are extended vertically through dry floors, they must be totally enclosed and unventilated to maintain safety and compliance with electrical standards. The specific minimum distance requirement above the floor is set at 6 feet. This stipulation helps to ensure that the busway, which may carry substantial electrical current, is adequately protected from accidental contact and potential hazards, such as water intrusion or mechanical damage, typically found lower to the ground. This height requirement is particularly important in commercial and industrial settings where safety measures must prevent unauthorized access and provide sufficient clearance from the ground.