NEC Article 225.30 Raceways for More than One System> (A) Raceways with Conductors of Different Systems. Conductors of different systems shall not occupy the same raceway, cable, box, or cabinet unless one of the following conditions is met:>> (1) Expressed Permission. The installations are made in accordance with specific written permission of an authority having jurisdiction.>> (2) Single Conductors. Single conductors of different systems shall not be placed in the same raceway, cable, box, or cabinet where any conductor carries over 300 volts.>> (3) Insulation. Single conductors of different systems shall not be placed in the same raceway, cable, box, or cabinet unless they are insulated for the maximum voltage of any conductor in the installation.>> (4) Neutral Conductor. The neutral conductor of a multiwire branch circuit supplying a 2-wire branch circuit shall not be placed in the same raceway, cable, box, or cabinet with the conductors of the 2-wire branch circuit, except as permitted for serviceentrance conductors in Article 230, Part III.>> (B) Circuits of Different Systems Occupying the Same Raceway, Cable, Box, or Cabinet. Where circuits of different systems do occupy the same raceway, cable, box, or cabinet, the system voltages shall be identified, and any conductor of the higher voltage system shall be colored or identified by some other suitable means.>> (C) Circuits of Different Systems Occupying the Same Enclosure. Conductors of different systems shall be separated by a barrier when installed in the same enclosure.

NEC Article 312.8 Disconnecting Means Required for Each Service> Where multiple services are installed on the same premises and are connected to a common distribution system, each service shall have a readily accessible disconnecting means located on the premises. Two or more disconnecting means shall be permitted to be located at a common location. The disconnecting means for each service shall be grouped together and identified.

Interpretation

Based on these NEC articles, it is generally not permitted to have two separate meters for different systems in the same raceway or pull box. However, there are a few exceptions: Specific written permission

If an authority having jurisdiction (AHJ) specifically approves it, then it may be allowed.

Single conductors

Single conductors of different systems may be placed in the same raceway or pull box if they are insulated for the maximum voltage of any conductor in the installation.*

Neutral conductor: The neutral conductor of a multiwire branch circuit supplying a 2-wire branch circuit may be placed in the same raceway or pull box with the conductors of the 2-wire branch circuit, as permitted for service-entrance conductors in Article 230, Part III.In your case, since you have two separate meters for a 150,000 sq. ft. building, it is likely that the systems are different (e.g., normal power and emergency power). Therefore, it is recommended to keep the two systems completely separate in all manners. Flag for review