Searching for NEC Code reference for service disconnect location
Article 230
  Services
  
  VI. Service Equipment — Disconnecting Means
  230.70 General
  
  Means shall be provided to disconnect all conductors in a building or
  other structure from the service-entrance conductors.
  
  (A) Location.
  
  The service disconnecting means shall be installed in accordance with
  230.70(A)(1), (A)(2), and (A)(3).
  
  (1) Readily Accessible Location.
  
  The service disconnecting means shall be installed at a readily
  accessible location either outside of a building or structure or
  inside nearest the point of entrance of the service conductors.