A good wired Local Area Network (LAN) in your home and office can provide you with reliable networking capability. Once you have your network set up you’ll be able to share server files, use a network printer, stream audio/video, link PC’s through a network switch and more. Knowing the type of cable to use for your networking project is important. In this article we will outline the differences between network cables used in networking project so it becomes easier to understand which ones to use for each specific project.
Basic Types Of Cables
There are over a dozen types of network cable types that are used in networking projects. However, we’ll only cover the following three types of cables in this article because they are the most commonly used in home and small business network installations: Category 3 (CAT 3), Category 5 (CAT 5), and Category 6 (CAT 6).
CAT 3 Cables: This type of cable isn’t used much anymore. Category 3 (CAT 3) cables have traditionally been used for installing phone lines or alarm systems in homes and small businesses. CAT 3 cables are constructed with two, three or four pairs. When you use a 2-pair cable, this allows you to support two phone lines. Using three pairs or four pairs gives you the flexibility to have extra lines available incase any problems arise with the other pairs or they can be used to add an additional third or fourth line. The reason that CAT 3 cables aren’t used much anymore is because CAT 5 or CAT 6 cables can be used for everything CAT 3 cables are used for plus a lot more. There is no need to run a CAT 3 cable and a CAT 5 cable when the CAT 5 cable is capable of satisfying all of your networking requirements.
CAT 5 Cables: Category 5 network cables are the most widely used networking cables because of their diverse capabilities. CAT 5 cables are not only used to draw phone lines but they can also support 10 base-T Networks or 100 base-T Networks (10/100) making them ideal for computer networking projects. Recently, CAT 5 cables have been improved upon to support what are called Gigabit Ethernet networks (otherwise known 1000 base-T networks). These newly improved cables are referred to as CAT 5e (or CAT 5 Enhanced) cables. CAT 5e cables are better insulated in order to reduce interference between the cables. The CAT 5e specification improves upon the CAT 5 specifications by more specifically defining existing crosstalk specifications while also introducing new crosstalk specifications that were not present in the original CAT 5 specification. Both CAT 5 and 5e have the same physical cable construction and support the same 100MHz bandwidth capability. In reality, most Cat 5 cables meet the Cat 5e specifications, though they are not tested or certified as such.
CAT 6 Cables: Category 6 network cables are starting to take the place of CAT 5e cables because the price difference between CAT 5e and CAT 6 cables has diminished thus allowing for future proofing your network. CAT 6 cables are designed for Gigabit Ethernet (i.e. 1000 base-T) networks but they can be used for any project that CAT 3, CAT 5 or CAT 5e cables would be used in.
The Variations within Each Type of Cable
Each of these three cable types comes in variations. For example, as outlined above, CAT 5 cables also come in CAT 5e (enhanced) versions. The same holds true for CAT 3 and CAT 6 cables. In this section we’ll explore the technologies that account for the differences between these variations.
MHz Ratings for Cables
In order to provide a sense of comparison, cable manufactures often measure the cable type by the maximum bandwidth that the cable can sustain. This brings the consumer some sense of clarity when choosing which type of cable to use. However, measuring cable bandwidth through MHz rating (or bandwidth) alone doesn’t paint the whole picture so it shouldn’t be the only factor to consider when choosing a cable. The table below outlines the bandwidth and network types that each type of cable can handle.
|Standard||MHz Rating||Highest Network type||Comment|
|CAT 3e||16MHz?||10||RARE, Not official|
|CAT 5||100MHz||100||No longer recognized|
|CAT 5e||350MHz (or 400MHz)||1000||Not Recognized|
|CAT 6e||550||1000||Not Recognized|
You will notice that CAT 5e is listed twice. In one listing it supports 100MHz and in the second listing it supports 350MHz (or 400MHz). The reason for this double listing is because the standards bodies designate that in order for the cable to be designated as CAT 5e it has to be able to sustain 100MHz of bandwidth. However, many manufacturers have improved upon the CAT 5e cable and can show bandwidths of up to 350MHz or more. Since the standards bodies have not specifically designated this, a bandwidth of 350MHz is generally “not recognized” but still accepted.
Therefore, the difference between CAT 5 and CAT 5e isn’t derived from the bandwidth that the CAT 5e cable can support. Instead, CAT 5e has better insulation and materials in order to reduce cross talk (otherwise known as signal bleed) or interference between the cables.
Similarly, CAT 6, CAT 6E and CAT 6a are actually all very similar. However, at 10GBe (or 10 gigabit Ethernet) CAT 6 or CAT 6E cables may exhibit some cross talk issues. As a result, CAT 6a cables were specifically designed to minimize this. CAT 6a cables contain additional measures in them to reduce cross talk. One example is the addition of spline, which separates the pairs in the network cables and significantly cuts down on the cross talk.
Shielded Twisted Pairs (STP) vs. Unshielded Twisted Pairs (UTP)
Network cables are constructed in two basic types: STP (Shielded Twisted Pairs) and UTP (Unshielded Twisted Pairs). Both have the same Ethernet communication performance but STP has better protection against electro-magnetic noise from the outside. Incidentally, STP cables come in a variation called FTP (or Foil Twisted Pair). In general, network installers use UTP cables in most projects because UTP is acceptable for most residential and general commercial installations. It only makes sense to use STP cables when you are running cables in certain conditions that require the shielding provided with STP cables. If you were to rank the level of shielding between these cable types, STP (shielded twisted pair) would provide the most shielding followed by FTP (foil twisted pair) and then UTP.
Unless you have some special circumstance, UTP is all you need. Shielded cable is more complicated to use and install. For example, the shielding will not properly work if the shield is not properly grounded.
STP – Shielded Twisted Pair: Shielded cables are useful for environments where proximity to RF equipment may introduce electromagnetic interference or when you want to minimize the likelihood of eavesdropping. With shielded twisted pair cables, each pair of wire is covered in a plastic covering (typically clear), which is then covered with a metal foil not unlike that used in coax cable. An un-insulated metal drain wire runs the length of this foil material and the whole thing is then wrapped in another thicker insulation. The shielding on the cable is designed to eliminate external interference from typical industrial sources.
UTP – Unshielded Twisted Pair: UTP cables are constructed with a pair of wires, a piece of twine and an outer sheathing for insulation. Unlike the STP cables, each pair is NOT covered in a plastic covering and a metal foil.
PVC Jackets, Plenum Rated and Outdoor Cables
Another consideration to make when choosing your networking cable is to think about where the cable will be installed. For example, if you’re just doing a simple network installation in the wall of your home then cables with a PVC jacket will be just fine. On the other hand, if you are planning to run wires through the plenum space in a building, then you need cables that are plenum rated. Plenum refers to the separate space provided for air circulation, heating and venting in a house or commercial space. Here is some further information about the various options available.
PVC Cables: PVC is the most common kind of network cable. PVC is commonly used as the covering for both patch cables and bulk cables. When burned, PVC covered cables release a toxic smoke so they are not normally used in air handling spaces. It is acceptable, however, to use PVC cables for in wall installations as long as local fire codes allow for it.
Plenum Rated Cables: Plenum cable is cable that is laid in the plenum spaces of buildings. Plenum rated cables (or just “plenum cable” for short) are network cables that have a covering that doesn’t emit a toxic smoke when they burn. Plenum-rated cables are slower to burn and produce less smoke than other cables. Plenum cable is jacketed with a fire-retardant plastic jacket of either a flame retardant low-smoke polyvinyl chloride (PVC) or a fluorinated ethylene polymer (FEP).
As mentioned above, plenum refers to the air handling space typically found in construction sites. The name comes from the air handling space provided for air circulation, heating, and venting in a house or commercial space. In a standard commercial building, the plenum is the space between the drop ceiling and the structural ceiling. In residential installations the plenum may include the space above the ceiling or under the floor when floor level air circulation is used. Plenum cables are usually screen-printed with external markings that read, “Plenum” or “CMP (Communications Plenum)” along the cable itself.
Riser Cables: Cable that is run between floors in non-plenum areas is rated as riser cable. The fire requirements on riser cable are not as strict. Thus, plenum cable can always replace riser cable, but riser cable cannot replace plenum cable in plenum spaces.
Both plenum and riser cables commonly include a rope or polymer filament with high tensile strength, which helps support the weight of the cable when it is dangling in an open chute.
Cables like twisted-pair, coaxial, HDMI, and DVI are available in both plenum and riser versions. The cable cost is often significantly higher than general-use cable due to the special restricted-use flame retardant materials.
Environmental Ratings: The following are US & Canada fire certifications for network cables:
|CMP||Communications Plenum||Suitable for installation in ducts and plenums without the use of a conduit. Designed for fire resistance and low smoke and toxin producing characteristics. Insulated with fluorinated ethylene propylene (FEP) and polyethylene (PE) and jacketed with low-smoke polyvinyl chloride (PVC), due to better flame test ratings.|
|CMR||Communications Riser||Engineered to prevent the spread of fire from floor to floor and are suitable for vertical shaft applications. Insulated with high-density polyolefin and jacketed with low-smoke polyvinyl chloride (PVC).|
|CMG||Communications General purpose||Complies with UL-1581 testing. Will burn and partially self extinguish. Not for use between build floors or in air plenum spaces. Often these cables are used for workstation cables and patch cords.|
|CM||Communications||Cables mainly used for general building wiring. Used in areas other than plenums and risers. These cables are resistant to the spread of fire and are insulated with high-density polyolefin but not jacketed with PVC and therefore is lower in flame resistance when compared to CMP and CMR cables.|
|CMX||Communications Residential||Complies with UL-1581 testing. Will burn and partially self extinguish. Not for use between build floors or in air plenum spaces. Often these cables are used for workstation cables and patch cords.|
|CMH||Complies with UL-1581 testing. Will burn and partially self extinguish. Not for use between build floors or in air plenum spaces. Often these cables are used for workstation cables and patch cords.|
Armored Cable, Outdoor Cable, Aerial Duct Cable, Direct Burial: For extreme environments there are a number of solutions available. In general these types of cables have the following possible additional characteristics:
Flooded Core / Poly-Filled: Almost all outdoor cables and most other kinds of armored cables have a water resistant gel encasing the pairs of wires. This helps prevent water from directly contacting the wire and corroding it.
Teflon Tape: In Network cables with Teflon tape, the wire pairs are wrapped in Teflon tape before getting an outer coating. This is usually done in conjunction with Poly Gel to provide an additional layer of water protection.
Drain Wire/Shielding: This type of shielding is applied in addition to other water resistant features such as poly gel or Teflon tape to provide more protection from the elements.
Armor Coating / Toughened outer insulation: Outdoor cables have a stronger outer covering to help prevent abrasion damage to the cable in projects where the wires are buried in outdoor settings.
Stranded Cables vs. Solid Core Cables
Network cables generally come in solid or stranded versions and neither one is appropriate for all types of projects. Solid core wires come with a solid 22-24 gauge copper wire. Stranded wires are constructed with many small threads of copper twisted together to add up to 22-24 gauge.
Solid Core Cables: When deciding whether to use solid core cables, it is worth considering this rule of thumb. In general, you use solid core cables with wall jacks or (keystones) and patch panels. This is because termination becomes easier and more reliable with solid core wires. Moreover, solid core wires have very good T properties, which means that they are easier to send signals over them. While they may achieve better signals, they are normally less flexible than stranded cables. As a result, they are not suited for bending or sharp corners. In general, solid core cables are best suited to be used in walls and for building wiring.
Stranded Cables: Alternatively, stranded cables are typically used with standard network cable connectors such as RJ45 connectors or 8P8C connectors. These are ideal when creating patch cables to connect network devices together, especially since they are more flexible and are easier to bend. As a result, stranded cables are best suited for projects that require the flexibility of patch cables to connect network devices together. You can use this cable to connect devices with RJ45 jacks such as a computer to a printer, router, switch box or other network components in a wired Local Area Network (LAN).
Stranded Category Cables have a higher attenuation than solid category cables. Therefore, depending on your application, you should restrict their use to short distances. In general, stranded category cables should be used for applications under 6 meters or 20 feet. Stranded cables are more expensive to manufacture and as such are more expensive than solid conductor cables for the equivalent length.
These days, there are a lot of low quality network cables on the market. It’s important to use high quality network cables so you don’t experience diminishing network transmissions over time. Ideally, you will want to use network cables that are made with pure copper. There are, however, many cables in the market that use a less expensive combination of aluminum that is coated with copper. This lower-grade cable is known as CCA cable. CCA stands for Copper Clad Aluminum. CCA wire uses an aluminum conductor that is coated with copper and it is less expensive than pure copper. The use of CCA wire in twisted pair network cables are not permitted by the IEC or CENELEC cable standards. Moreover, 3P, an organization that provides third party testing for compliance with industry standards for cable manufacturers, strongly advises against the use of CCA wire in twisted pair network cables. The use of CCA wire directly contravenes both CAT5e and CAT6 specifications, which denote the use of copper conductors.
CCA has higher attenuation properties than pure copper cable. This will result in more packets of data having to be retransmitted when they are corrupted or lost at the physical layer. This effect is particularly prevalent on longer cable channels on or near the 100 meter maximum and will at best lead to a slower network for most users of CCA twisted pair cables.
In addition to less desirable electrical qualities, CCA wire presents a number of physical problems for installers ultimately leading to delay and additional expense. CCA wire has a lower tensile strength than pure copper and, as a result, can be damaged through pulling. CCA wire in twisted pair applications also has less tolerance for bend radius.
In summary, there are a lot of options when it comes to network cables. However, most projects are handled with just a handful of cable types. While CAT 3 cables were traditionally used to run phone lines, these days CAT 5 and Cat 6 cables provide the flexibility to complete telephone and networking projects without the need for CAT 3 cables. If you want to “future proof” your network, you can simply use CAT 6 cables because they provide the most diversity and bandwidth for your project. Most projects don’t need a shielded cable so you will be fine using UTP or Unshielded Twisted Pair type cables. Only if you’re working in extreme environments is when you’ll need to use STP or Shielded Twisted Pair type network cables. Moreover, use outdoor rated cables if you plan to directly bury your cable or run it exposed to the elements or if it will be occasionally exposed to moisture. When deciding whether to use solid core cables or stranded cables, remember that solid core cables are better suited in the wall or ceilings while stranded cables are ideal when connecting network devices together, especially since they are more flexible and are easier to bend.
When you’re ready to buy an Ethernet Network Cable, visit our website to see all of the great options we make available for you. If you have any further questions please don’t hesitate to contact us. You can e-mail us at: firstname.lastname@example.org or call toll free at 888.488-2635.