Mike Dolt Enterprises
Mike Dolt Enterprises
User: stevet, Location: New York
Asked on: Monday, April 11, 2011 at 3:13 pm EDT
Answered on: Tuesday, May 14, 2024 at 4:03 am EDT
Question: Hello,In a large Building that has a small sub station with switchgear, is it possible the Main Disconnect for the Bldg., is located outside in one of the cubicles? These are accesible by the Line crew, who work at the campus.I may be wrong, but I always thought the Main Service Disconnect had to be in the Bldg. If it is allowed outside, away from the Bldg., then the first disconnect in the Bldg., would be considered a sub panel?Thanks - Good Day
Yes, it is possible for the Main Disconnect for a building to be located outside in one of the cubicles in a small substation with switchgear.NEC Code Requirements
The National Electrical Code (NEC) does not explicitly require the Main Disconnect to be located inside the building. However, it specifies certain requirements for the location and accessibility of service disconnecting means (main disconnects).
NEC 225.30
The service disconnecting means shall be located where it is readily accessible and operable by qualified persons.
NEC 225.40
The service disconnecting means shall be outside the building or at a readily accessible location outside the building.
Accessibility Considerations
While the NEC does not prohibit the Main Disconnect from being located outside, it is important to consider accessibility for maintenance and emergency purposes. The following factors should be considered:
Accessibility for Line Crew
If the Main Disconnect is located in a cubicle outside, it should be easily accessible to the line crew who may need to respond to power outages or perform maintenance.
Accessibility for Building Personnel
If the Main Disconnect is the primary means of disconnecting power to the building, it should be readily accessible to authorized building personnel in case of emergencies.
Subpanel vs. Main Disconnect
If the Main Disconnect is located outside, the first disconnect inside the building would typically be considered a subpanel, as it is a secondary service disconnecting means. However, it is important to follow the manufacturer's instructions and local building codes to determine the proper classification.
Conclusion:
Yes, it is permissible for the Main Disconnect for a building to be located outside in one of the cubicles in a small substation with switchgear. However, it is crucial to ensure that accessibility and safety considerations are met. Flag for review