sundance-communications.com/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring Riser Cable

Here in Northern Michigan, you can generally use regular cable for just about anything. Downstate however, you want to use Plenum cable (period, end of sentence).

I have since seen a new grade of cable: Riser Cable.

Supposedly, it's for pulls in between floors.

Does anyone use this grade of cable? Is it even required?

Riser cable has been around ALMOST as long as I have. And, yes, it is required due to fire ratings. Now then, where I am I use plenum / non plenum cable as needed because that is the way it is, not due to local requirements...there aren't any. Same for riser. Seldom is it needed here, but it is used when necessary.

its all the local suppliers carry , nothing new.

we've used it for a few years , not out of choice but its all thats stocked .

when you go to the counter here and ask for non plenum its what you get

Same as skip

CMR= non plenum Riser Rated Also called PVC
CMP= Plenum rated cable
CM= vertical tray rated (I've never seen it)

I've heard the CM meaning both communications and communications meeting.

We can use Non Here in PA, but generally use CMP in offices.

Checkout this page they discribe wire types in layman terms

CM= Communications Multipurpose. About all you going to find around here is CMR since it costs about the same as CM.

One thing you have to be careful with is coax. Coax follows the same convention only with a CATV prefix, thus CATV, CATVX, CATVR, CATVP. It is quite common to get unlisted cable which will not have any of these designations. That's because when its used outside of the building or house no listing is necessary and that's what cable companies order and suppliers stock. When I order coax I always specify CATVR otherwise I'll get the unlisted stuff.

-Hal

CM = Communications
CMR = Communications Riser
CMP = Communications Plenum

In most non-plenum horizontal settings you can use regular CM. The riser rating in CMR is for a specific riser application, but most manufacturers just make their "non-plenum" cable variant to be riser in order to cut down on the number of cable types they have to mfg and stock.

One exception that I know of off hand is Systimax. Their non-plenum cable is CM by default (known as the "C" version). If you want CMR then you have to order the "B" version.

In the industry non-plenum cable has become synonymous with "PVC," but plenum cable is also made of PVC (polyvinylchloride), albeit a chemically altered version that reduces the smoke toxicity when burned.

Hans

I have always thought that riser cable was just non-plenum regular cable and that plenum cable was only used in ceilings where breathed air passed around the cable. Is this true?

No, CMR with the R designation is riser cable. I have seldom seen and never ordered anything but CMR for non-Plenum, but you do find it on jobsites from time-to-time.

I don't think the National/reputable houses even stock CM cable today.

Carl