Return air plenum wiring

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tonype

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I've been reading about plenum rated wiring - I am assuming that this applies to supply as well as return?

Anyway, photos below are from a 4-story condo building - the electric-heated air handler is in an air space between the 2nd and 3rd floors (I was only looking at one of the condo units - not the entire building). Photos below show air handler (just sucks air in - no filter - nice eh?; however, the HVAC end is another story). There is all kinds of wiring in the area (also, some wiring that is routed from this area to another area - breaches what I think is supported to be a rated wall for the plenum return). I'm thinking that this is potentially a hornets nest to tackle. I've never seen this before. Would welcome any comments.

http://i15.photobucket.com/albums/a352/TonyPE/P1040681_edited-1.jpg
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http://i15.photobucket.com/albums/a352/TonyPE/P1040671_edited-1.jpg
 
tonype said:
Marc:

How does this affect all the wiring in the plenum?
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You're asking me? I'm just a regular electrician. That's the kind of stuff we ask PE's. If you ask me, everything in that space between the unit's ceiling and the deck above needs to be suitable for plenum wiring.
 
mdshunk said:
You're asking me? I'm just a regular electrician. That's the kind of stuff we ask PE's. If you ask me, everything in that space between the unit's ceiling and the deck above needs to be suitable for plenum wiring.
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Don't sell yourself short - I find that those in the trades know alot more than some PE's with book smarts. Also, it is amazing how often I look at plans (especially for homes and small buildings) only to find very limited electrical info by the design professional - just showing where outlets, lights and switches - no service equipmetn schedules, etc (the drawings invariably leave this stuff to the EC). This is why I hang out here to learn (I perform pre-purchase building inspections - all aspects of a building - but my design work is limited to structural and mechanical).
 
I am thinking it is time to pack up and go to another job..this one will cost lots and probably never get paid..that is a home made hot water heat exchanger..do they have an outside wood boiler..run I say run..even if this is cash and no permits..
 
cschmid said:
..do they have an outside wood boiler....
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Unfortunately, the roof was not accessible. It appears that there is a heat pump, possibly with supplemental elec. resistance somewhere. The access hatch to the area was only about 12" x 18" and I had to jam a ladder through shelves to get there. Most photos were taken with my arm reaching up into the area and snapping away in various directions.
 
tonype said:
Marc:

How does this affect all the wiring in the plenum?
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Well, I am not Marc, but it looks like you have major violations of 300.22(C).

Edit to add: Be careful of the word "plenum". As used in the NEC, a plenum is a constructed and enclosed chamber for the sole purpose of moving air. The space you show seems to be an "other space used for environmental air".
 
ryan_618 said:
Be careful of the word "plenum". As used in the NEC, a plenum is a constructed and enclosed chamber for the sole purpose of moving air. The space you show seems to be an "other space used for environmental air".
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This is a difficult one - this area is enclosed (except for some after construction holes) and is separated by gypsum board walls from the rest of the space that is between the 2nd floor ceiling and the 3rd floor framing above.
 
If that space is a plenum, why is it insulated against the interior spaces? I have a suspicion some hack HVAC work was done post-construction that turned it into a plenum that wasn't meant to be.
 
LawnGuyLandSparky said:
If that space is a plenum, why is it insulated against the interior spaces? I have a suspicion some hack HVAC work was done post-construction that turned it into a plenum that wasn't meant to be.
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You may be correct - though I suspect that this was "approved" when installed, since the air handler is the same age as the building (1974). And this building is located in Hudson County, NJ - enough said.
 
As Ryan pointed out, this space is not a 'plenum' to the NEC, which would have severe restrictions as found in 300.22(B).

That space for whatever reasons is 'other space' covered by 300.22(C) and has less restrictions then true plenums.

Either way NM in that space is a violation of the current code but may not have been in violation at the time of installation.
 
In the intrest of safety i would call the fire chief and building department.Even if its legal (i dought it) it sure is a mess.Nails just waiting to get some worker.If it is return air i dought romex could be allowed.
 
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