Section 230.70/Service Disconnecting Means
NEC 230.70 covers the location, marking, and accessibility requirements for the service disconnecting means, which must be at a readily accessible location nearest the point of entrance of service conductors.
The service disconnecting means must be installed at a readily accessible location nearest the point of entrance of the service conductors. It must be installed either outside the building or inside nearest the point of entrance. Section 230.70(A)(1) allows the authority having jurisdiction to require the disconnect to be located outside the building. The disconnect must be suitable for the conditions and clearly marked to identify it as the service disconnect. Per Section 230.71, a maximum of six switches or circuit breakers may serve as the service disconnect, mounted in a single enclosure or grouped at a single accessible location. Where the service disconnect is not within sight of the meter, a permanent label at the meter must indicate the location of the disconnect.
Why this section exists
The service disconnect is the last point of protection between the utility and the building's electrical system. Emergency responders must be able to locate and operate the service disconnect quickly to de-energize a building during a fire or other emergency. The "nearest the point of entrance" requirement minimizes the length of unprotected service conductors inside the building. The six-disconnect rule limits the number of switching operations needed to fully de-energize the building. Many jurisdictions now require exterior disconnects for firefighter access.
What plan reviewers look for
Plan reviewers locate the service disconnect on the electrical plan and verify it is at or near the point of service entrance. They check that the disconnect is readily accessible. They verify the disconnect is marked "Service Disconnect." They check the six-disconnect rule if multiple disconnects serve as the service. They verify the disconnect rating matches the service-entrance conductor sizing.