Master Electrician Exam (NEC)Special Occupancies, Equipment, and ConditionsHard
A master electrician is installing a single-phase, 120V, 100A service to a mobile home. According to NEC Article 550, what is the minimum height requirement for the attachment point of the service-drop conductors to the mobile home?
- A8 feet above finished grade.
- B12 feet above finished grade.
- C10 feet above finished grade.
- D15 feet above finished grade.
Show answer & explanationAnswer & explanation
Correct answer: C. 10 feet above finished grade.
NEC 550.10(A) specifies that the service-drop conductors must have a minimum clearance of 10 feet in all directions from the mobile home, including the attachment point, and from the area above the mobile home roof. This ensures adequate clearance for safety and maintenance.
Why the other options are wrong
- A. 8 feet is generally too low for service drop clearances over areas accessible to pedestrians only.
- B. 12 feet is a common clearance for service drops over residential driveways, but 10 feet is the specific minimum for mobile homes.
- D. 15 feet is typically for service drops over public streets or areas subject to truck traffic.
Mobile Home Service Drop Clearance (NEC)
The National Electrical Code (NEC) mandates specific minimum clearances for service-drop conductors to mobile homes, requiring at least 10 feet in all directions from the mobile home and its roof area for safety.
- Minimum 10 feet clearance from mobile home.
- Applies to service-drop conductors.
- Ensures safety for occupants and maintenance personnel.
Memory trick: Mobile Home Drop: Ten feet all around, for safety on the ground and up high.