2020年9月8日 · The plenum is the space or structure the air flows in in an HVAC system. Most often in commercial buildings the space above the ceiling is the return plenum for the HVAC system (as opposed to ducted returns). A ceiling that uses the space above the tiles as the return plenum is usually referred to as a plenum ceiling.

2024年8月16日 · So I have this project where the area above the strut grid is a plenum space. I am installing EMT and 4 Square J-boxes. I have been looking for some verbiage in the NEC code book where it would state that all J Boxes and Fittings need to be listed for plenum air spaces, but cannot find it. I did read 300.22 (c)(1)

2011年12月12日 · Not sure if this has been addressed before, but can anyone provide a code section that requires junction box's (1900 / 411's) to be plenum rated in a space that is used for air handling? 300.22(C) refers to "metal enclosures", 314 wasnt helpfull either.

2014年10月12日 · if the area is used as a giant duct to move air, then it's a plenum. If the giant duct isn't a duct, but an area like the area above the ceiling, it's called an environmental air space (it didn't always used to be like this). read the link below on Holts. if all the supplies and returns are ducted/flexed to grid, then it's not a plenum.

2023年4月4日 · A lot of people don't realize, but AC90 is not FT6 either, but it has been accepted to be used in plenum space. I would run AC90 or conduit in the plenum space then transfer to something that is suitable to go to the unit. Most units I have done in the past, the AC90 can go right into the unit through the ceiling, no issues.

2014年1月30日 · A plenum is not just any open space in which air may flow, it is a space specifically dedicated to carrying environmental air: Plenum . A compartment or chamber to which one or more air ducts are connected and that forms part of the air distribution system.

2009年11月11日 · The return air plenum is in the ceiling joist area (no metal duct), between the downstairs wall and an upstairs wall stack heading up to the furnace. I have 9" of clearance in this plenum area. With the HALO (7" tall) mounted in the 4" soffet, once this protrudes into the ceiling area, it will leave me about 6" to play with.

2016年3月17日 · A plenum is any space that is intended to have pressurized air flowing in it, either supply or return. So a duct is a plenum, but a plenum is not necessarily a duct, if you get my meaning. Cable that is plenum rated has a flame spread rating that …

2021年8月31日 · There is plenum rated ENT, but whatever you run in the ENT must also be plenum rated, which will be a show stopper for power wiring. In a non-plenum space above ceiling tiles, it' allowed, but I'd be prepared for inspectors to hate it, and you better have every i dotted and t crossed. Look at the rules for independent support, etc.

2012年11月7日 · This is why we always plan for plenum rated wire in commercial bids. Are you referring to the 2011 changes 300.22(C)(2)? New Section 300.22(C)(2) was added to cover wiring supported by cable trays in other spaces used for environmental air.