Mike Dolt Enterprises
Mike Dolt Enterprises
User: absolutesantaja, Location: Waynesboro, Tenneesee
Asked on: Tuesday, April 26, 2011 at 1:18 pm EDT
Answered on: Tuesday, May 14, 2024 at 4:38 am EDT
Question: First of all I'm primary residential but me and another LLE are volunteering some time to wire a small steel building for our local church. The inside has wooden frame installed in front of the metal for sheetrock and drop ceiling to attach to. Now I know that NM is now allowed above the drop ceiling and we will be running MC as much as I dislike dealing with it but what is easier for the walls? Go ahead and run MC for everything or run NM and put metal junction boxes above the fake walls and swap over. 2008 Code references would be appreciated and yes I have searched the forum and have only found references for junction boxes above the drop ceiling and NM not being allowed in non dwellings.Thanks and sorry for confusing everyone.
2008 NEC References
[300.22(C)](https://www.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-codes-and-standards/detail?code=70): Types of Nonmetallic Cable (NM) and Nonmetallic-Sheathed Cable (NMC) Permitted for Use [314.23(F)](https://www.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-codes-and-standards/detail?code=70): Uses Not Permitted [334.30(B) and (C)](https://www.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-codes-and-standards/detail?code=70): Type MC Cable [312.8](https://www.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-codes-and-standards/detail?code=70): Enclosure, Type and Size
Analysis
NM cable is not permitted in non-dwelling occupancies, including churches, per [314.23(F)](https://www.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-codes-and-standards/detail?code=70). Type MC cable is permitted in both dwelling and non-dwelling occupancies per [334.30(B) and (C)](https://www.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-codes-and-standards/detail?code=70).
Recommendation
Based on the NEC,
Type MC cable should be used for both the walls and drop ceiling for this project.
Rationale
MC cable is permitted for use in non-dwelling occupancies and is more durable than NM cable. Running MC cable for everything will ensure consistency and avoid the potential issues associated with switching from NM cable to metal junction boxes. While it may be less desirable to work with MC cable, its suitability for this application outweighs the convenience factor of NM cable.
Enclosure Requirements: When using Type MC cable, metal junction boxes must be used per [312.8](https://www.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-codes-and-standards/detail?code=70).* The junction boxes must be placed above the drop ceiling and below the metal frames for accessibility. Flag for review