Residential Furnace closet, running Romex through.

[glene77is]

In looking at some previously roughed-in work, I noticed the furnace/airblower unit is to be installed in a closet (standard residential method). I noticed that the bedroom circuits have romex passing through the plenum (return air) box, which will be under this unit. Romex passes from one bedroom to an adjacent bedroom, straight through the plenum return air box. This return air box is the typical 2x4 framed box which supports the typical heater/air blower unit. The air is to be pulled from the floor in the hallway, and blown out through ductwork in the attic to the various rooms.

Any Comments or NEC references
on passing romex through a plenum box ?

 

[Dennis Alwon]

If it traverses the return duct perpendicular then it is fine but it cannot run parallel in the duct.. Look at 300.22(C) exception.

Are the wires on the floor????

 

[glene77is]

If it traverses the return duct perpendicular then it is fine but it cannot run parallel in the duct.. Look at 300.22(C) exception.

Are the wires on the floor????

Thanks. I had looked at 300.22, and did not recognize anything applicable to this residential installation. I guess this is not a plenum, just a 'return air box' ( under the heater/ac-coil and blower). This is like a little closet, with the unit sitting up 1 foot off the floor. The return air duct is on the floor level.

This is a residential, with a heater/ac-coil and blower.
This is a typical residential install.
There is a 2x4 frame supporting the unit.
The air is pulled in from the floor of the hallway, then forced up through the attic ductwork to the various rooms.
The east bedroom receptical circuit runs into this chamber,
then along the top of the 2x4 plate (which is part of this framed box),
and then into the west bedroom, and immediately to the west bedroom receptical box.

Usually, we find these recepticals going around the wall, daisy chain style,
from one receptical to the next.
But this one went through the return air box.
I think it is a violation, and will check, eventually, with code enforcement,
just for my own interest.

Hope I said that better.