Plenum Rated Ethernet

[drozwood90]

So...I have a good idea where to look for cheap ethernet cable...

But, where is a good place to look for Plenum cable (bulk).

I'm imagining that this is going to be the cheapest LV type cable that I can get, that will allow me to pull cables INSIDE the heating ducts.

I'm just pulling to get to my powered registers, low current.

Heck, I'd even settle for non-ethernet plenum rated 22/2 or something else...

key ideas, low current (3.3V, ~.2A Peak i.e. NON-Continuous draw), low cost, MUST be plenum rated.

The cheaper the better!

I'm GUESSING that I need 500-700 feet. However, ATBE, 1000' roll is fine.

--Dan

 

[mdesmarais]

You can often buy partial boxes on ebay. . .

 

[sda]

allow me to pull cables INSIDE the heating ducts.

I hate to be a code book thumper, but that's not allowed per the NEC.

 

[drozwood90]

allow me to pull cables INSIDE the heating ducts.

I hate to be a code book thumper, but that's not allowed per the NEC.

Why do you say that? I didn't see anything in the code book...

Is there something in particular you saw that made you say that?

--Dan

 

[CollinR]

This was my understanding as well, although I don't have the black and white I know I would never do it.

The term plenum is usually discribing the return air ducting in commercial buildings. Many times return ducts go from floor to floor beside elevators and staircases, this is where I use plenum wire. Never actually inside a duct itself. Some buildings the return is above a drop ceiling in which case the entire area above the drop ceiling is a plenum and would require the wire.

Still I don't run anything inside a residential return either but commercially sometimes you cannot avoid areas like this.

 

[Photon]

CollinR said "Still I don't run anything inside a residential return either but commercially sometimes you cannot avoid areas like this. "

My new house has lots of wiring, 117VAC wiring - not data, inside the return-air pathways . The return-air registers are in the walls near the ceiling. An unlined stud bay connects to metal ducting below floor level. The electricians took no detours around these bays as they pulled their horizontal runs around the rooms. I don't see where any of this wiring says it is plenum rated.

I fully agree with CollinR, and I ran none of my low voltage stuff through these spaces. That doesn't mean we don't have wiring in our plenum-like spaces though.

 

[sda]

allow me to pull cables INSIDE the heating ducts.

I hate to be a code book thumper, but that's not allowed per the NEC.

Why do you say that? I didn't see anything in the code book...

Is there something in particular you saw that made you say that?

--Dan

Since you indicated these cables are for register control, I think they fall under

ARTICLE 725— CLASS 1, CLASS 2, AND CLASS 3 REMOTE-CONTROL, SIGNALING, AND POWER-LIMITED CIRCUITS

725.3.( C ) Ducts, Plenums, and Other Air-Handling Spaces.
Class 1, Class 2, and Class 3 circuits installed in ducts,
plenums, or other space used for environmental air shall
comply with 300.22.

300.22
( B ) Ducts or Plenums Used for Environmental Air. Only
wiring methods consisting of Type MI cable, Type MC
cable employing a smooth or corrugated impervious metal
sheath without an overall nonmetallic covering, electrical
metallic tubing, flexible metallic tubing, intermediate metal
conduit, or rigid metal conduit without an overall nonmetallic
covering shall be installed in ducts or plenums specifically
fabricated to transport environmental air. Flexible
metal conduit shall be permitted, in lengths not to exceed
1.2 m (4 ft), to connect physically adjustable equipment
and devices permitted to be in these ducts and plenum
chambers. The connectors used with flexible metal conduit
shall effectively close any openings in the connection.
Equipment and devices shall be permitted within such ducts
or plenum chambers only if necessary for their direct action
upon, or sensing of, the contained air. Where equipment or
devices are installed and illumination is necessary to facilitate
maintenance and repair, enclosed gasketed-type luminaires
shall be permitted.

This topic has been debated numerous times on various forums when people want to pull cat5e or coax or anything else in their ducts and they've been shot down by professional electricians and inspectors.

 

[sda]

My new house has lots of wiring, 117VAC wiring - not data, inside the return-air pathways . The return-air registers are in the walls near the ceiling. An unlined stud bay connects to metal ducting below floor level. The electricians took no detours around these bays as they pulled their horizontal runs around the rooms. I don't see where any of this wiring says it is plenum rated.
though.

I think there's some exception that says you run can wiring across return air stud spaces.

Is your system air conditioning only? It would seem like putting return vents near the ceiling would pull the warmest air out of the room.

Hopefully they remembered to caulk the holes and joints or you're sucking unconditioned air from adjoining stud bays.

 

[Photon]

Both heat and A/C. When I was young, all the heat came out high and returned low. Now it is opposite. I think it is because they favor the A/C season with its higher cost per BTU.