Where can I find rules on the use of non-metallic cables & raceways above drop ceilings that are used for air returns? I thought there were prohibitions, but I can't find anything in the articles on- LFNC, LFMC, or RNC.
Redsy, See 300.22(C). In general you cannot use nonmetallic raceways, however if this is a Chapter 8 application there are some nonmetallic raceways that are permitted. See 800.51(J) for an example. One brand of this stuff looks just like electrical nonmetallic tubing except that it is orange. Don