NEC Commercial Electrical Practice Test

What is the minimum vertical clearance required for overhead service-drop conductors above the roof surface?

1. 6 feet

2. 7 feet

3. 8 feet

4. 9 feet

The correct answer is: 8 feet

The minimum vertical clearance required for overhead service-drop conductors above the roof surface is 8 feet. This clearance requirement is crucial to ensure safety and prevent any potential contact with the conductors from equipment or personnel working on the roof. The 8-foot clearance allows for normal roof maintenance activities and decreases the risk of electrical hazards. This specification is outlined in the National Electrical Code (NEC), which serves to establish safe electrical installation guidelines. Maintaining this clearance helps mitigate risks of accidental electrocution, especially in residential or commercial settings where roof access might occur. The other clearance options are not sufficient as they do not meet the NEC requirements to ensure adequate safety when dealing with overhead electrical lines. This regulation (typically found in NEC sections addressing overhead conductors) emphasizes public safety and promotes best practices in electrical installations.