For a 277/480-volt, 3Ø, 4-wire service, what is the minimum clearance required above the roof?

The minimum clearance required above the roof for a 277/480-volt, 3Ø, 4-wire service is indeed 8 feet. This requirement is based on National Electrical Code (NEC) provisions that ensure safe distances between conductors and structures. Sufficient clearance minimizes the risk of electrical hazards and allows for maintenance and operation without interference from roofing materials or any other infrastructure.

For this voltage level, maintaining an 8-foot clearance helps ensure safety during maintenance activities, prevents accidental contact, and reduces risks associated with wind or other environmental factors that could impact the stability of overhead service drops. This requirement is crucial for safeguarding both electrical personnel and the general public, ensuring that any electrical service infrastructure maintains a safe operational environment.

While specific definitions of the clearance may vary by jurisdiction, adhering to the NEC guidelines, which favor an 8-foot minimum, is commonly recognized as best practice in the electrical installation field.