Cabling

Joining the Network Together

Cabling is the common bond that ties all the other equipment together, including wireless devices to some degree, and that is the Ethernet network cabling. In the past coax cable using either a BNC or coax connector were commonly used. These cables were bulky and somewhat inflexible.

Ethernet cabling is now the de facto cabling and there are basically six Ethernet network cable categories that are in use today.

Maximum Cable Lengths

The maximum length a cable can run without signal boosting is 328 feet, (100 meters.) This is because of a factor known as attenuation which is the loss of signal strength because of the reduction of the amplitude of the signal. To prevent this loss on cable runs over said distances, a switch is needed to boost the signal. The use of a switch is the preferred method.

Cable Categories

  • Category 3 Cabling

    Cat 3 cable is used for telephone wiring. It is an unshielded twisted pair, (UTP) cable and is less commonly known as voice-grade, (VG) wiring.

  • Category 5 Cabling

    Cat 5 cable is a twisted pair, (TP) cable for carrying signals. It is used in structured cabling for computer networks such as Ethernet. This standard provides performance of up to 100 MHz and is suitable for 10BASE-T, 100BASE-TX (Fast Ethernet), 1000BASE-T (Gigabit Ethernet), and 2.5GBASE-T.

    Cat 5 is commonly connected using punch-down blocks and modular connectors. Being unshielded, for noise reduction it relies on the balance line twisted pair design and differential signaling.

    Cat 5 cable is still in use but is becoming obsolete. Some cable supply companies have even quit selling this type of cable.

  • Category 5e Cabling

    Cat 5e (enhanced) is currently the most commonly used in new installations. Cross-talk is greatly reduced with this cable. Cat 5e is better at keeping signals on different circuits or channels from interfering with each other. Additionally, it can handle 1000 Mbps speeds (gigabit Ethernet) at 100 MHz which Cat 5 cabling cannot.

  • Category 6 Cabling

    Cat 6 cable improved over cat 5 as it is suitable for up to 10 gigabit Ethernet at 250 MHz. Cat 6 also has an internal separator that isolates pairs from one another. Additionally, the twists in the wiring is tighter to better cancel cross-talk and allows two-way communication on each pair. It consists of 23 or 24-gauge wire and can have a maximum distance of 328 feet, (100 meters) before a signal boost is required.

  • Cat6a Cabling

    Cat 6a also can be 23 or 24-gauge wiring and is thicker than Cat 6. It has the extra-thick plastic around the wires themselves, and partly due to the tighter winding of the pairs themselves, creating more copper per inch. Cat 6a will do 10 Gigabit per second networking for the full distance of Ethernet at 328 feet, (100 meters.)

  • Category 7 & 7a Cabling

    With Cat 7 and 7a, a fast 10 Gigabit Ethernet speed can be obtained and then some. Cat 7 has pair-sharing capability, making it possible to use one cable to power several different devices at the same time utilizing each pair as needed. For the best and most versatile infrastructure Cat 7 provides the solution.

Wiring Characteristics

Wire Types

There are three basic network wiring types, each having their own purpose and characteristics.

UTP & STP CableUnshielded Twisted Pair, (UTP): This is the most commonly used cable. It does not have any protective shielding. It is mostly used in traditional homes and offices. It is not intended to be used in some situations such as areas that require fire-retardant wiring or near machines that generate EMF.

Shielded Twisted Pair, (STP): This cable is used in areas where interference from EMF would cause interference with the data traffic running over the cable. This cable has a metal shielding between the outer insulation and the wiring; in some cases each wire is insulated itself.

Plenum Cable: Plenum cable got its name from a HVAC term Plenum Spaces which is the space above drop ceilings where air circulates to aid in the heating or cooling of a building. Though this cable does not look physically different that the other two cables by outward appearance, it does provide a level of protection from toxic gases created if this cable is subjected to fire. This type of cable is coated with a fire-retardant material, usually Teflon® that will cause the cable to smoke less should it catch fire and thus reduce any toxic gases created by the burning of the cable.

The degree of wire twists

Ethernet Wire Twists As mentioned, some cables are better in reducing noise and cross-talk. This is mainly due to how tightly the wires are twisted together. With a tighter twist, more copper wire is used and this helps reduce noise and cross-talk.

Here are three examples of the different degrees of twists that are found in Cat 5e, 6 and 6a Ethernet cabling. As these twists are increased, so is the difficulty in working with these wires. Only with working with the tighter twisted wiring can you gain the confidence working with this degree of twisting.

Solid versus Stranded

Solid Versus Stranded Cable Solid UTP Category cables have solid insulated bare copper conductors. These cables are used in permanent and semi-permanent installations. They are designed for longer distance horizontal and backbone cable runs, PoE (power over Ethernet) and HD applications. Solid Category cables should not be over-flexed, bent, or twisted beyond the cable recommended specifications. All Cat5e and Cat6 solid UTP cables are designated with minimum bend radius for performance standards. Proper cable installation is essential to maximize the performance of the cable.

Stranded UTP Category cables have multiple strands (typically 7 strands per conductor) of insulated bare copper conductors. These cables are typically used for patch cords/cables connecting workstations; from wall plate outlet to patch panel; and from patch panels to individual workstations. Because these cables are more flexible than solid conductors, they are excellent for portable uses and applications where repeated flexing is common.

Cabling Tools

There are specialized tools that are designed just for network cabling. It is important not to scrimp on your cabling tools as they need to be of high quality to get your cabling job done right . . . the first time!

Some of these tools can be substituted by general hardware, but there are tools that are specialized and designed specifically for network cable installation and troubleshooting.

Cable Installation Tools

The most common cable installation tools include:

  • Wire Strippers
  • Scissors
  • Crimping Tool

Wire Strippers

Wire StripperThis might be one of the tools that you can find a substitute for. In other words, the wire stripper you use does not have to be specially designed for network cables.

Whether you get your wire stripper from a network cable supply house or your local hardware store, make sure you purchase one that is durable and sturdy. Most of the tools you will use to create cables will be dropped at some time or another, so, your tool should be able to take some punishment.

Scissors

ScissorsScissors are another tool that don't have to be specifically made for network cables. You can use any small pair of scissors providing they have a small enough tip. These scissors are used for snipping small pieces of network cabling, mainly the insulation. They can also be used for other wiring issues.

If you purchase an non-network type of scissor, make sure they can cut wiring without dulling. This is a feature that a good pair of network scissors has over a regular pair of sissors.

Crimpers

RJ-45 CrimperThis is one tool that you cannot substitute. These tools are multi-purpose and can be used to cut network wires square so they can fit evenly into the RJ-45 connector. They can also be used to strip the insulation off the network cable and lastly, and most importantly, provides the method for crimping the network cable to the cable connector. Most crimpers can crimp both RJ-45 and RJ-11 connectors.

The way this tool works for crimping a connector to a cable is simple. Once the cable wires are inserted into the connector, the connector is then placed in the appropriate receptacle, (RJ-45 or RJ-11.) The handle is then squeezed tightly and firmly until the cable connector has been crimped down on the wiring making the electrical connections.

Cable Testing Tools

The most common cable testing tools include:

  • Cable Testing Meter
  • Tone Generator & Probe

Here is where things can get a bit pricey. These tools are necessary for testing and maintaining your network cabling and cannot be ignored. Depending on your network testing and maintenance needs, these tools can run just under $100 to a couple of thousand dollars.

Cable Meter

Network MeterThere are as many meters made today as there are needs. Not all meters can test the same things, and this is where you should do your homework before purchasing a meter that either more than you need or worse, won't work for your testing needs.

The meter shown here, the Fluke Microscanner® will test a variety of cables such as PoE, (Power over Ethernet) and voice data cables as well as traditional data cables. It is one of the mid-range priced network testing devices available on the market.

The advice given is again to shop before you spend your money on a network cable testing device. There is no need to spend hundreds of dollars for equipment that may be more than you need. However, think growth as well. If you think that you may need to expand your testing for other services in the future, then purchased the equipment you may need now instead of having to eventually spend additional funds in the future.

Tone Generator & Probe

Tone & ProbeA tone generator & probe is a tool used to test and troubleshoot RJ-45 and R-J11 cables and individual wires. It can be used to trace a network cable that usually would be difficult to locate.

The Tone Generator creates the signal and the Probe when run along a network cable will detect the signal and produce the tone.

For example, if you were to run multiple cables from a server room to different wall plates and didn't mark the cables beforehand, a tone & probe can find exactly what cable is going to what port in a patch panel. This is a lot easier than the hit-and-miss method to locate or trace a cable.

Tone generators and probes are inexpensive in comparison to cable testing meters and most are under $100.