Rules for IT Equipment Rooms

Status
Not open for further replies.
L

lj

Member
Location
Tampa, FL, USA
NEC 322(D) says that wiring in air-handling areas beneath raised floors for information technology equipment shall be permitted in accordance with Article 645. NEC 645 requires a means to disconnect power to all electronic equipment in the information technology equipment room. So, if all the underfloor wiring is in conduit (EMT or LFMT), is there anything else that says we must comply with NEC 645? We are trying to get away from having a disconnecting means. Thank you.[/quote]
 
I can't find a 322(D), I think that you meant 300.22(D), but will attempt to answer your question. The creation of an IT room under Article 645 allows electrical installations that are more permissive than in the first four chapters of the NEC. For example wiring in a raised floor that is used for environmental air can be types prohibited elsewhere in the NEC for use in environmental air spaces. In IT rooms designed according to Article 645 the area under the raised floor is not considered a plenum space. This allows wiring below the floor to be nonplenum rated cables.

The one caveat to Article 645 installations is that the room must meet all five of the conditions outlined in 645.4. If it fails to meet any of these conditions the room can not take advantage of the less restrictive wiring methods covered under this article. Therefore, without meeting all five conditions, the use of LFMC (I am assuming you meant LMFC, not LFMT) would be prohibited.
 
Rules for IT Equipment Rooms

Trevor, thank you for catching two typos. I did mean NEC 300.22(D) and conduit type LFMC. After studying NEC 645 again, it seems that if the data center does not take advantage of less restrictive wiring methods allowed by NEC 645.5, then it does not have to comply with NEC 645.4 requirements. In other words, as you said, if the underfloor installation complies with NEC Chapters 1-4, then the data center is not considered an IT equipment room, and the requirements of NEC 645.4 (including disconnecting means) do not have to be met. Thank you.
 
After studying NEC 645 again, it seems that if the data center does not take advantage of less restrictive wiring methods allowed by NEC 645.5, then it does not have to comply with NEC 645.4 requirements. In other words, as you said, if the underfloor installation complies with NEC Chapters 1-4, then the data center is not considered an IT equipment room, and the requirements of NEC 645.4 (including disconnecting means) do not have to be met.
Click to expand...

I agree with that just in case you were looking for a third opinion :)
 
I am grateful to Steve66 and Ron for their replies. Looks like all agree. Special thanks to Ron for supplying the link to the excellent article interpreting NEC 645.
 
Status
Not open for further replies.
Top