Riddle Me This- Plenum

[mobiledynamics]

Just thinking outloud.....as I start the estimating/etc for my new office space out here in Gotham City....the land of BX/Cable....

Seems in most commercial applications, plenum on LV is generally run, regardless if it's going inside a Plenum or Not. Obviously, there is a cost associated with that. Me wonders whey there are not similar restrictions/guidelines on why Plenum electrical cabling is not required.

 

[rockwithjason]

I am thoroughly confused by your question.

 

[wyliesdiesels]

Just thinking outloud.....as I start the estimating/etc for my new office space out here in Gotham City....the land of BX/Cable....

Seems in most commercial applications, plenum on LV is generally run, regardless if it's going inside a Plenum or Not. Obviously, there is a cost associated with that. Me wonders whey there are not similar restrictions/guidelines on why Plenum electrical cabling is not required.

Thats just logic and common sense. Dont use it if it isnt required.

The only thing u will be hurting is your wallet if u use it where its not needed...

 

[mobiledynamics]

The OP meant to say, if we have such restrictions on LV in Plenum space, why would it not apply to electrical lines. Granted, there is probably alot less electrical lines in the plenum cavity versus a bundle of LV wires.

Not sure where code dictates for you, but the new code for us is that it needs to be supported every 4 1/2 feet not attached to anything/lashed else.

The other post was confirmation or not....that whether in Plenum or NOT, in commercial spaces in NYC, is Plenum required for ALL commercial spaces irrelevant of Plenum Space or Not. ALL I've ever seen in comm. spaces is Plenum, regardless of whether it's in the Plenum or just running against a wall..

 

[wyliesdiesels]

Sounds like youre asking about NY code specifics...I cant answer that since Im on the other side of the country...

 

[jeffmoss26]

I do a lot of low voltage work and pretty much always use plenum.
I don't think plenum rated THHN exists, if the wire is in conduit or MC I don't think it would matter.

 

[zmaxmotorsports]

I am thoroughly confused by your question.

 

[Cmreschke]

Correct jeff moss. I believe it must be metallic though.

 

[pacecar]

Like jeff said, most commercial electral is run in conduit/emt with individual conductors so plenum rated cable is superceded by the use of emt. Technicallly if low voltage(cat5e or other) is run in conduit (I think) you can use non plenum pvc if you wanted. Im in texas and would advise you to talk to your local inspector or look up the code for your local municipality, but if memory serves I think that was my understanding.

Plenum rated cables pass a fire test where the product either doesnt burn or burns slowly enough and the gases produced when burned are withing a particular limit for a certain amount of time. Basically its suppose to give an individual time to exit the building without being knocked out or killed as a result of the burning cable.

 

[Stuff]

This is confusing. The rules basically say MC cable is plenum rated but BX/AC is not.