Code Q&A

Is liquidtight flexible metal conduit (LFMC) permitted under the raised floor of a computer room? If yes, must it be secured?

Mike Holt

July 25, 2006

Q. Is liquidtight flexible metal conduit (LFMC) permitted under the raised floor of a computer room? If yes, must it be secured?

A. It depends on what you mean by a computer room. If you are talking about an information technology equipment (ITE) room as per 645.4, the answer is yes. However, it must be secured in accordance with 300.11 [645.5(D)(2)]. Note: Power cables and associated boxes that are listed as part of, or for, information technology equipment are not required to be secured in place [645.5(E)].

If the computer room does not qualify as an ITE room, and the raised floor is not used for environmental air, the answer is still “yes” if secured in accordance with 300.11. But, if the computer room does not qualify as an ITE room, and the raised floor is used as an environmental air space (for air-conditioning) then LFMC can’t be used at all in this space [300.22(B)(1)].

About the Author

Mike Holt

Mike Holt is the owner of Mike Holt Enterprises (www.MikeHolt.com), one of the largest electrical publishers in the United States. He earned a master's degree in the Business Administration Program (MBA) from the University of Miami. He earned his reputation as a National Electrical Code (NEC) expert by working his way up through the electrical trade. Formally a construction editor for two different trade publications, Mike started his career as an apprentice electrician and eventually became a master electrician, an electrical inspector, a contractor, and an educator. Mike has taught more than 1,000 classes on 30 different electrical-related subjects — ranging from alarm installations to exam preparation and voltage drop calculations. He continues to produce seminars, videos, books, and online training for the trade as well as contribute monthly Code content to EC&M magazine.