The plenum space, however, is not limited to housing only HVAC equipment. It is increasingly being utilized for other purposes, such as routing communications cables, including networking cables. This versatile use of plenum space is a response to the evolving infrastructure needs of modern buildings, where efficient space utilization is crucial. The plenum thus plays a dual role in both maintaining a building's climate control and supporting its communication and network systems.
●Cat6 (Category 6): Cat6 cables offer higher performance compared to Cat5e, supporting faster data speeds and better handling of crosstalk, making them suitable for more demanding network environments.
●Cat6a (Category 6 Augmented): As the most advanced and expensive option, Cat6a cables provide the highest specifications among the three. They support even higher data speeds and have enhanced features to reduce crosstalk and electromagnetic interference, making them ideal for high-speed networks and demanding commercial applications.
All these plenum Ethernet cables feature a twisted pair design, which is a standard in the industry to minimize crosstalk and electromagnetic interference. The choice between these types depends on the specific network requirements, budget, and the level of data transmission performance needed.
The National Electrical Code is a set of guidelines describing procedures which minimize the hazardsof electrical shock, fires, and explosions caused by electrical installation. The text of the NEC is contained in nine chapters, each chapter broken into individual articles. NEC types are acronyms consisting of a prefix
describing cable type (e.g. coax, CATV, fiber optic) and a suffix indicating the type of flame test it has passed and where it can be installed. Articles describing wire and cable products — including required cable markings — are listed in the chartto the right.
Almost everyone involved with wire and cable is affected by the National Electrical Code. In particular, the following groups must incorporate NEC guidelines into their work: OEM engineers, wire and cable product engineers, distributors, installers, and architects. Although NEC covers wire and cable installed in factories, office buildings, hotels, motels, apartment buildings, residences, and all cables which pass through any floor, wall, ceiling, or which travel in ducts, plenums, and other air handling spaces, each individual municipality, city, county, or state can decide whether or not they wish to adopt the NEC as law. Local authorities having jurisdiction enforce their own codes. They have the right to accept or refuse any installation in accordance with their own local laws. One of the organizations local inspectors rely on to test wire and cable is Underwriters Laboratories (UL).
In the past, AWM cable was incorrectly used to wire buildings—this was never its intended use. AWM cable is intended for internal wiring of factory-assembled, listed appliances such as computers, business machines, ranges, washers, dryers, radios, and televisions. In some cases, AWM cable may be used for external connection. In these situations, the user should be aware that AWM cable temperatures and voltage ratings may differ from NEC ratings.
UL/NEC-Approved cables may also be C(UL)/ CEC-Approved as communications cables meeting the requirements of the Bi-National Standard CSA C22.2 No. 214/UL 444 and Section 60 of the Canadian Electrical Code, Part I (CEC). The C(UL) cable designation (and its meaning) would be one of the following:
1. CMP — Cable meeting CSA FT6 or NFPA 262
(UL 910);
2. CMR — Cable meeting UL 1666;
3. CMG — Cable meeting CSA FT4;
4. CM — Cable meeting UL 1685 (UL 1581, Sec. 1160)
Vertical-Tray;
5. CMX — meeting UL 1581, Sec. 1080 (VW-1);
6. CMH — Cable meeting CSA FT1. NOTE: The CSA flame tests are defined in CSA C22.2 No. 0.3 as follows:
A finished cable shall not propagate a flame or continue to burn for more than one (1) minute after five (5) fifteen (15) second applications of the test flame. There is an interval of fifteen (15) seconds between flame applications. The flame test shall be performed in accordance with Para 4.11.1 of Canadian Standards Association (CSA) Standard C22.2 No. 0.3. In addition, if more than 25% of the indicator flag is burned, the test cable fails.
The FT4 Vertical Flame Test — Cables in Cable Trays is similar to the UL-1685 Vertical Tray Flame Test, but is more severe. The FT4 test has its burner mounted at 20° from the horizontal with the burner ports facing up. The UL-1685 Vertical Tray has its burner at 0° from the horizontal. The FT4 samples must be larger than 13mm (.512”) in diameter. If not, then the cable samples are grouped in units of at least three (3) to obtain a grouped overall diameter of 13mm. The UL-1581 Vertical Tray does not distinguish on cable size. The FT4 has a maximum char height of 1.5 m (59”) measured from the lower edge of the burner face. The UL-1685 has a flame height allowable up to
approximately 78” measured from the burner.
This test is for cables which must pass a Horizontal Flame and Smoke Test in accordance with ANSI/NFPA Standard 262-1985 (UL-910). The maximum flame spread shall be 1.50 meters (4.92 ft.). The smoke density shall be 0.5 at peak optical density and 0.15 at maximum average optical density.
CMP, CMR, CMG, CM, CMX | Communications Cables |
CL3P, CL3R, CL3, CL3X, CL2P, CL2R, CL2 | CL2X Class 2 and Class 3 Remote-Control, Signaling and Power Limited Cables |
FPLP, FPLR, FPL | Power Limited Fire Alarm Cables |
CATVP, CATVR, CATV, CATVX | Community Antenna Television and Radio Distribution Cables |
OFNP, OFNR, OFNG, OFN | Nonconductive Optical Fiber Cables |
OFCP, OFCR, OFCG, OFC | Conductive Optical Fiber Cables |
PLTC | Power Limited Tray Cables |
BMR, BM, BLP, BLX | Network-powered Broadband Communications Cable |