Answer :
Final answer:
The closest distance NMD90 cable can come to floor level without requiring protection is 1.5 meters, ensuring it is above the zone of typical activity where it might be damaged.
Explanation:
When installing NMD90, which is a type of electrical cable, on the face of a stud in a building, there is a specific height above the floor at which the cable does not require additional protection. According to building codes and standards, the correct answer to the question "What is the closest distance NMD90 can come to floor level without protection?" is 1.5m. This means that if the cable is installed lower than 1.5 meters above the floor, it must have some form of protection to prevent damage. Higher than 1.5 meters, the assumption is that it is out of the zone of routine activity and less likely to be damaged.