e57
Senior Member
- Location
- San Francisco, CA
Check these out....
http://www.draperinc.com/Lifts_Mounts_Brackets/VideoProjector_Lifts.htm
http://www.draperinc.com/Lifts_Mounts_Brackets/VideoProjector_Lifts.htm
Plenum Box installation: SO cord
- Thread starter soundcon
- Start date
- Status
- Location
- Massachusetts
e57 said:
Mark, I think that the smoke issue is entirely covered by 300.22. which does not allow flexible cords in any plenum.
IMO 400.8(2) is all about the concealed damage aspect.
How about a metal enclosure installed up into the ceiling, isolating it's own interior from the plenum, containing a hard wired receptacle for the projector, in a similar manner as a bathroom exhaust fan motor plugs into the receptacle in it's enclosure?
Code compliant or not, this idea makes for a good, long sentence.:smile:
Code compliant or not, this idea makes for a good, long sentence.:smile:
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realolman said:
This is EXACTLY the configuration we have here. A fully enclosed box whose interior is isolated from the plenum area. A standard receptacle, UL approved, mounted in a UL approved handy box using either flex or EMT to provide power to the handy box. The projector's power cable is run into the (sealed form the plenum area) plenum box through a 1 1/2" NPT pipe which runs through the ceiling tile and opening into the room above the projector.
If there were to be a fire inside the plenum box it could not possibly get into the plenum space. Possibly some somke could escape around the edges of the box but no more so than boxes that contain power interface for things already approved and installed in plenum areas now.
The power cable from the projector would NEVER enter the plenum space.
As stated by someone else in this thread, Da-Lite should submit this for consideration. Jim
- Location
- Massachusetts
realolman said:
I agree, but it is still above the ceiling.
That would be a violation of 400.8(5).
For the above to be compliant someone has to put in a code proposal for a change.
Preventing human loss highest priority
Preventing human loss highest priority
I am not interested in running any flexible cable in the plenum area. We have removed many hundreds feet of brand new, non plenum, low voltage cable improperly installed. We refuse to touch or modify non-plenum cable installed in a plenum space on work we are repairing. Either we do not do the work or the customer agrees to have us replace the wire to bring the installation up to code. In a previous lifetime I spent 25 years in the commercial floor covering business where I did a great deal of study into the flame spread and cumbustion support issues. Let me be real clear here: I am not looking for a way to circumvent safety concerns. If what I want to do can't be done and provide total safety then I am not interested in pursuing it.
I am more than familiar with the FSR products you refer to and specify and install them all of the time. Frankly, I fail to see, as a practical matter, any difference between the FSR solution and the Da-Lite solution other than for the UL approval.
Bangladesh..... OMG I actually would like to see some of the practices done here tightened up, not loosened up. Jim
Preventing human loss highest priority
e57 said:Soundcon, what I think you are looking for in appearance is available in the floor..... Get one for the ceiling approved and you got a market....
However the reasoning - and I am now stepping into very deep water here - ceilings of the plenum flavor serve as environmental air for the HVAC system, and thus become part of the breathable air in a building when the worst happens. i.e. Fire.... And the propose of not allowing flexible cords in that area above the ceiling is to limit smoke, and fire travel on combustible materials. e.g. Plenum rated Cat-5 cabling is both lower in toxic smoke when burning, and has a lower rate of flame travel by UL testing. The chemical compounds in just about all flexible cords that make them 'flexible' are not produced in a way that could qualify as 'low smoke or flame spread'.... The NFPA and UL are not looking to add any more load to that type of area where it would be both concealed, more prone to fire, and be more toxic, and be inside essentially part of the duct work.... And as Iwire mentioned - the NEC does not want to open the pandora's box of allowing cords being used as premise wiring, as not only are the life-spans of said cordage lower, but the installation of said would then allow many other nasties into the pool - next thing you know we'll be using the non-methods of the hack.... cords to flying splices in walls - whole buildings wired in lamp cord with various voltages and we soon become Bangladesh.....
I am not interested in running any flexible cable in the plenum area. We have removed many hundreds feet of brand new, non plenum, low voltage cable improperly installed. We refuse to touch or modify non-plenum cable installed in a plenum space on work we are repairing. Either we do not do the work or the customer agrees to have us replace the wire to bring the installation up to code. In a previous lifetime I spent 25 years in the commercial floor covering business where I did a great deal of study into the flame spread and cumbustion support issues. Let me be real clear here: I am not looking for a way to circumvent safety concerns. If what I want to do can't be done and provide total safety then I am not interested in pursuing it.
I am more than familiar with the FSR products you refer to and specify and install them all of the time. Frankly, I fail to see, as a practical matter, any difference between the FSR solution and the Da-Lite solution other than for the UL approval.
Bangladesh..... OMG I actually would like to see some of the practices done here tightened up, not loosened up. Jim
- Location
- Massachusetts
realolman said:Or this..... ...
That works and many projector mounts come with a spot to do just that.
e57 said:
It may have been a verbal conversation or some such process of determining the application. I may have assumed I could do this and Da-Lite may not have implied anything. However, what is the point of the receptacle (clearly shown in their drawing) in the plenum box if not for plugging in the projector and power supply for a low voltage device. If the low voltage power supply is plugged into the receptacle it also has a flexible cord housed in the very plenum box where I wan to put my projector cable. The only difference is that the projector power cord comes from inside the room through the metal pipe into the box while power supply cord never enters the room. The same 1 1/2" NPT pipe is going into the room whether or not the projector power cord comes through it or not.
It appears that the code stipulating the flexible cable not penetrating a ceiling or wall is blind to the possibility that may be an acceptable application that would create an exception to the rule.
Yes the way we do it now
Yes the way we do it now
Yes, the very box assembly we are speaking of from Da-Lite has the knockout in the face pan part of the bracket. We have been installing them this way since we started installing projectors in dropped ceilings. But this does not address the very issue I am getting at here. How is this any more safe than running the cord 10" inside a sealed plenum bux, either from flame spread or smoke density in the plenum space?
How about some sort of non-flexible cable, plenum approved, in place of the standard cable that comes with the projector. Might this option work?
Yes the way we do it now
iwire said:That works and many projector mounts come with a spot to do just that.
Yes, the very box assembly we are speaking of from Da-Lite has the knockout in the face pan part of the bracket. We have been installing them this way since we started installing projectors in dropped ceilings. But this does not address the very issue I am getting at here. How is this any more safe than running the cord 10" inside a sealed plenum bux, either from flame spread or smoke density in the plenum space?
How about some sort of non-flexible cable, plenum approved, in place of the standard cable that comes with the projector. Might this option work?
- Location
- Massachusetts
realolman said:
You want to split hairs all day long we can I got time,:smile: but out on the job it costs real money.
If the inspector sees a power cord going up through a hole into the 'ceiling' it is likely going to be a problem.
Change the code or change the problem but as it is presented here IMO it is a very clear violation.
Perhaps the projector manufacturers could start providing a way to hard wire the units cleanly?
iwire said:
I think the inspector would be incorrect to cite the power cord as being in voilation if the surface of the box that separates it's interior from the space above the suspended ceiling surface is visible.
How about if the whole riggins, box and all, was below the suspended ceiling? Would it be a violation then? Looks to me like a great big "in use" receptacle cover.
They just want to make a nice looking job and have even taken the plenum thing into consideration. I think if the entire box is above the ceiling, then yes, it probably wouldn't fly, but if its lid was exposed, and it didn't pass, then there'd be hairs split alright, but it ain't me doin it:smile:
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walkerj
Senior Member
- Location
- Baton Rouge
I don't understand why you cant just cut an outlet into the ceiling tile:-?
I think you guys are overthinking this or I'm confused
I think you guys are overthinking this or I'm confused
stickboy1375
Senior Member
- Location
- Litchfield, CT
walkerj said:
I'm confused also, what on earth is so hard about having the receptacle installed next to the projector?
- Location
- Massachusetts
walkerj said:
stickboy1375 said:
Having the receptacle cut into the tile facing down or into the mount facing down has been suggested a few times.
The OP does not want it to show, IMO they have no choice.
e57
Senior Member
- Location
- San Francisco, CA
If it (the drawing you posted) came from them - they need new tech support - not the one in Bangladesh.... Or you may be you may have misunderstood, as there would be a 1G metal cut-in box inside the plenum cover - but installed in the method shown by realolman....soundcon said:
Anyway, my point about the floor access boxes is that the outlet is below the floor line - but is not in the floor - it is in the recessed (niche) access box that happens to be inside the floor.... Cords do not enter the floor and travel around the framing.
The DaLite product is not intended to act in the same way - or from my read of their spec's - promoted in a way to suggest that, although the instructions are particularly vague.... If you got that impression there must be some confusion of someones part, yours, or theirs....
Now for some more discussion about cords behind finishes.... Here are some examples of where it is done, and often....
- Jacuzzi Tubs - most often the cord fed motor and controls are behind an access in the tub-surround skirting.
- Hot-tubs, same thing...
- Floor access boxes of course
- Enclosures for networking, structured wiring etc.
- Cord connected items behind access panels.
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stickboy1375 said:
The reasoning was presented earlier in the thread but a synopsis here is that we want to hide the receptacle to make a cleaner more attractive installation. We can make almost everything disappear if we can figure out a way to get the A/C connection in the plenum box. for more detail see my inital couple of posts. Jim
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