Master Electrician Exam (NEC)Special Occupancies, Equipment, and ConditionsMedium
A master electrician is installing a new manufactured building that will serve as a permanent office space. The manufactured building is equipped with a 100-ampere, 120/240-volt service. Where is the main disconnecting means for this manufactured building required to be located?
- AInside the manufactured building, adjacent to the main panelboard.
- BIt can be located anywhere on the property as long as it is readily accessible.
- CAdjacent to the manufactured building, within sight and not more than 30 feet from the exterior wall.
- DAt the point of attachment of the service-entrance conductors to the building.
Show answer & explanationAnswer & explanation
Correct answer: C. Adjacent to the manufactured building, within sight and not more than 30 feet from the exterior wall.
NEC 545.13 states that the main disconnecting means for manufactured buildings shall be located adjacent to the manufactured building, within sight, and not more than 30 feet from the exterior wall of the manufactured building. This ensures that emergency personnel can quickly and safely disconnect power.
Why the other options are wrong
- A. While a disconnect is inside, the *main* disconnect for manufactured buildings has specific outdoor location requirements.
- B. Readily accessible is a general requirement, but manufactured buildings have a specific distance and 'within sight' rule.
- D. This is a general service disconnect rule, but manufactured buildings have a more specific distance and location requirement.
Manufactured Building Main Disconnect
Specific location requirements for the main disconnecting means of a manufactured building to ensure quick and safe power cutoff.
- Required by NEC 545.13
- Adjacent to the building.
- Within sight and not more than 30 feet from exterior wall.
Memory trick: Manufactured homes need their main switch nearby, '30 feet' max, like a close neighbor.