atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring running cable in plenum ceiling

ceiling plenum's aren't the norm around her so I don't have a lot of experience with them

new construction

each office drywall extends floor to building ceiling ( above drop ceiling ) there is a large cutout in each wall ,above the drop ceiling

maybe 2'x 3' can I pull my cables through this opening ?

its not firewall so theres no gate to drop to close it off

at this point I either pull through them or pop a hole through the walls

I don't see any reason not to (we are pulling plenum cable )

but I thought I'd ask

Rule of thumb is to never use someone elses penetration. Those holes may be for AC/heat ducting or something else. Play it safe and install your own sleeves through the walls. You can use metal conduit cut to extend 6 inches on each side of the wall but you will need to use bushings on both ends so as not to skin your cables. This has advantages because it clearly defines your pathway and you shouldn't have other vendors puling over top of you and burning your cables. It is much more professional!
My 2cents

Generally, the large openings are sized based upon the square footage of the isolated area. Inspectors don't like to see anything passing through these openings because technically, it's reducing the airflow capacity of the opening. True, you really should place your own metalling sleeve through the wall with bushings on either end. Arlington Industries makes some great little push-on bushings that allow you to simply use a scrap piece ot 1/2" or 3/4" EMT for the sleeve.

no the ac ducting is already in place Ive seen these openings in other plenum ceilig(and seen them used as wire paths )

Since its a plenum I believe there used as air return

so its not using someone else "penetration " per se its using open ceiling space

I know I can do sleeves but thats more time and money and since Ive already bid the job I'm looking to keep the costs/time down

well its not going to be inspected , since its not required for low voltage around here {yet}

other inspections are done since the ceiling tiles are going in this week , so really no one would know but I still like doing it right

ok I just did a goggle search for Arlington bushings and came up with this old thread here where Hal says they cant be used in plenum

https://www.sundance-communications.com/cgi-bin/ultimatebb.cgi?ubb=print_topic;f=24;t=000112

That is correct, since they are made of PVC. I have never had an inspector say anything about it though. To tell you the truth, I don't think that I have ever seen a plenum-rated bushing other than metal ones.

I have to go with Telcomtex and ev607797, but you said; No one would know (but i still like doing it right) go with your gut feeling's, but it's your name/company name that also goes with it. There's alway's someone at somrtime that's going to look up there at some point (next day, next year or whatever) and they all have comment's, one way or another, and they "never" can keep it to themself's, good or bad. Just saying it's your name/company name that your leaving behind.

There actually shouldn't be holes like that in those walls. That ruins the whole concept of keeping a fire barrier.

You should not run your wire through that opening. To keep to standard you need to put sleeves in a seperate part of the wall. Make cutouts for your sleeves and firestop all gaps around the sleeves.

these aren't fire walls

I have seen firewalls done this way with a gate type device that drops down to seal the opening

( I have also seen cable bundles run through them that would keep the gate from closing )