Plenum rated cables in air handling space?

[brantmacga]

Question on something I'm not entirely familiar with;

We have a mechanical room. Inside of this room are my 3 panels (flush mounted, metal enclosure/cover), two air handlers, air cleaner, alarm panel, and LV rack with network equipment, lighting system controllers, and distributed audio.

The mechanical contractor ran the returns to this room, and installed grilles in the ceiling, so the room is now an air handling space. There is a return duct that goes into an air cleaning system, which then pumps the clean air back into the room for the air handler to pickup and distribute back out.

From what I read, my panels are fine, but there is a lot of LV cabling that comes out of the wall and into the back of the rack. Is this requires to be plenum rated cable?

This was all design-build with no plans or specs, just a floor plan to work off. I did not do the LV install. This was a collaborative effort with an LV contractor. I'm asking though because we have a similar project going together where we were turned down because the mechanical contractor made the entire attic an air handling space, and they did not use plenum rated cable. The mechanical contractor is now running return ducts to all the air handlers, which I'm pretty certain they are going to rip out after the final. They said the system is not designed for and will not operate as intended using return ducts. They asked me to come back and install smoke shutdowns across the attic.

Anyway, this AHJ does not issue separate LV permits, but they will inspect LV when they come to look at mine, and will not issue a CO if the LV is not to code.

Long winded I know ...... thanks


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[tom baker]

Air handling spaces require plenum cable. The NEC calls these environmental air spaces.

 

[Smart $]

IMO, no.

300.22 Wiring in Ducts Not Used for Air Handling,
Fabricated Ducts for Environmental Air, and Other
Spaces for Environmental Air (Plenums). The provisions
of this section shall apply to the installation and uses of
electrical wiring and equipment in ducts used for dust,
loose stock, or vapor removal; ducts specifically fabricated
for environmental air; and other spaces used for environmental
air (plenums).

...

(C) Other Spaces Used for Environmental Air (Plenums).
This section shall apply to spaces not specifically
fabricated for environmental air-handling purposes but used
for air-handling purposes as a plenum. This section shall
not apply to habitable rooms or areas of buildings, the
prime purpose of which is not air handling.

 

[brantmacga]

Air handling spaces require plenum cable. The NEC calls these environmental air spaces.

Thanks .... where I'm getting confused is the mention of fabricated ducts being called a plenum.

So I'm reading through the code and here are my concerns. Where it says devices are permitted if associated with the equipment; there are receptacles in this room, and an LED strip fixture. The code mentions a gasketed fixture is allowed. I'm concerned my devices aren't allowed. I have a quad between the air handlers, and the receps for the rack equipment and alarm panel.

Here are the code sections I'm looking at .....

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[Smart $]

Thanks .... where I'm getting confused is...

The way I see it from your description, the mechanical room is definitely not a duct.

While the room may be used as a plenum, neither 300.22(C) or 725.135(C) apply because the room is a habitable room or area of the building, the prime purpose of which is not air handling. The term habitable could be called into question, but Code sets no criteria upon which to make an assessment. While I certainly wouldn't want to habitate in a mechanical room, ask a homeless person if he would?

 

[iwire]

The way I see it from your description, the mechanical room is definitely not a duct.

While the room may be used as a plenum, neither 300.22(C) or 725.135(C) apply because the room is a habitable room or area of the building, the prime purpose of which is not air handling. The term habitable could be called into question, but Code sets no criteria upon which to make an assessment. While I certainly wouldn't want to habitate in a mechanical room, ask a homeless person if he would?

I agree with Smart

 

[mgookin]

Two questions:

You mention 2 different jobs in Post #1. Which job are we talking about?

Is this in Florida?

 

[brantmacga]

The term habitable could be called into question, but Code sets no criteria upon which to make an assessment. While I certainly wouldn't want to habitate in a mechanical room, ask a homeless person if he would?

Read that also and had the same thoughts.



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[brantmacga]

Two questions:

You mention 2 different jobs in Post #1. Which job are we talking about?

Is this in Florida?

The first job. No this is Georgia; 5 miles north of the FL line.


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[mgookin]

The first job. No this is Georgia; 5 miles north of the FL line.


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We used to have to address this every code cycle. Between cabling and duct detectors, they kept flip flopping on every code cycle. It involves the bldg code, mechanical code, electric code and the life safety code. If it were in FL I could solve it for you with about 10 minutes of effort, but I've never worked in GA.

If you haven't been cited for it, and if it's not your work (hence not your liability) you may want to just let the sleeping dog lay. Hopefully your permit says "Electrical not including low voltage."

 

[JFletcher]

Does the air from that room go to a dedicated air handler, then back, w/o being dumped/pumped into the rest of the building? Does it meet the rest of the specs/reqs in article 645?