[5 Minute Read]
Q: What is structured cabling?
Structured cabling is the highway that information travels on in a building. The building can be large or small, commercial or residential, or a combination of both.
Structured cabling systems are designed around telecommunications code standards. They define how to lay cable in different topologies to ensure flawless continuity and connectivity. Some factors include distance limitations, cable types, flammability ratings, and bend radii. These standards are outlined by:
- TIA/EIA-568: The TIA (American Telecommunications Industry Association) and the EIA (Electronic Industries Alliance) issue comprehensive standards covering all aspects of cable installations.
- ISO/IEC 11801 - The ISO (International Standards Organization) and IEC (International Electrotechnical Commission) release material, manufacturing, and testing standards. These standards cover commercial communications: telephony, data, copper, fiber, etc.
- EN 20173: The European standards for structured cabling.
- BICSI: BICSI (Building Industry Consulting Services International) provides best practices around data center design. It complements the previous standards and addresses several subjects not covered by TIA. Most importantly, they issue RCDD (Registered Communications Distribution Designer) certifications.
Why does structured cabling even matter? It keeps you connected. Most of the technology you use is supported by structured cabling: Wi-Fi, VoIP, DAS, security cameras, audio visual systems, IoT sensors, and the list keeps growing. Following standards ensures that these technologies operate as designed when connected to the system.
Q: Should I use Cat5E, Cat6, Cat6A, or Fiber?
Category 5/6,/6A cable, single-mode fiber, and multi-mode fiber vary in capabilities and price.
Copper cable comes in many different flavors, but the most common are Cat5E, Cat6, and Cat6A. The speed, frequency, and cost increase with each level. According to TIA recommendations, Cat5E is legacy, Cat6 is the minimum, and Cat6A is recommended.
Fiber cable is divided into single-mode and multi-mode. It's immune to electromagnetic interference, provides more bandwidth, and can be run at longer distances. This extra functionality comes at a cost– installation and material are more expensive.
The right cable will depend on how big your facility is and how much bandwidth it’ll need.
Q: Do I need Plenum or PVC?
Using plenum or PVC (Polyvinyl Chloride) cable comes down to your building’s HVAC system.
Plenum cable is designed to operate in a “return air” space in the building. Typically these spaces are above a suspended ceiling or beneath a raised floor. They are a “return air” space because it's where HVAC systems get the air to the heat or cool.
Plenum cable is more expensive than PVC because of the less flammable compounds used in production. The cable must pass a burn test that measures flame spread and smoke emissivity when exposed to a flame of a certain intensity and duration. When plenum burns, it puts off less poisonous gas. Alternatively, PVC releases hydrochloric acid and dioxin as it burns.
If ever in question, the building inspector is typically the AHJ (authority having jurisdiction). An inspector can help you deal with the nuances since plenum cable may be recommended in certain areas even if the code doesn’t require it.
Q: Do I need 1 or 2 cables per work area?
This decision is a widely debated topic. The fact is, cable is inexpensive relative to the entire telecommunications system and building that it serves. The increased functionality and bandwidth from one more data cable can be priceless. Going back and adding cables can be expensive and cumbersome, especially after drywall is in place.
TIA/EIA-568-B.1 advises two drops per work area. Stating, “This Standard recognizes the importance of both voice and data telecommunications in a commercial building. A minimum of two telecommunications outlet/connectors shall be provided for each individual work area... Consideration should be given to installing additional outlets/connectors based on present and projected needs.”
Q: Should I compare Mhz?
Manufacturers design and test their cables to perform at specific frequencies depending on the applications intended to run over them. Category 6, for example, is designed to be tested up to 250Mhz and provide a positive signal-to-noise ratio out to that frequency. This capability enables gigabit ethernet to run as intended over the cable with an acceptable amount of packet loss. Cat 5e, on the other hand, was only designed to 100Mhz.
One should not get caught up in manufacturer claims of “tested to 350Mhz vs. 400Mhz”. The real question is, “what is the signal to noise ratio at the frequency of the system you are running.” You can test a barbed wire out to 1000Mhz, but it’s still barbed wire.
Q: What are test results about and why do they matter?
Test results are commonly required on all structured cabling jobs. The installer can use a handheld tester that plugs into the network and tests each cable for factors like wire map, distance, cross-talk, and ACR (signal to noise). These tests can are downloaded into a file and handed to the owner after project completion. Test results verify that the system installation meets industry standards and terminations were done correctly.
A Fluke tester is most common and supports TIA and ISO specifications for Cat5E and Cat6 cable. It provides Pass/Fail results. The example below goes over how to read standard fluke test results.
Q: What's the industry standard for a warranty?
Cabling system warranties eliminate confusion between the cable manufacturer and the connectivity manufacturer if the system has a problem. In the early days of structured cabling, there was mainly one cable and connectivity manufacturer. Now, many companies have legal agreements in place to support a single solution and warranty design.
Most connectivity and cable companies will tout a 25-year warranty. Truthfully, if the cabling system works after the contractor tests it, it should last every bit of 25 years. The exception being if someone does something to the system that materially alters or changes it. The electrons will not “quit working” one day. ASD® is proud to offer a lifetime warranty.
Q: What should the end deliverable be for a structured cabling system?
When properly designed and installed, the end deliverable should be a structured cabling system that supports the customer’s needs now and well into the foreseeable future. The MDF (Main Distribution Frames) and IDF (Intermediate Distribution Frames) should be well thought out, and cables should be neatly dressed. It should have additional cable runs that support a wireless overlay and have sufficient bandwidth in the backbone to handle a step-change in bandwidth needs. For the last 20 years, clients have utilized more bandwidth in the current year than the year preceding it, and this trend shows no sign of slowing down. We’ve never heard ever say, “we put in too much cable.”
Q: What should I budget for my structured cabling project?
Although we have this as our last question on the list, it’s often the first question we're asked. Unlike most vendors, we welcome this question and like to provide helpful information. From a rapid ballpark estimate to more detailed pricing based on your specific needs, contact us for a free estimate. In the meantime, learn more about pricing with our free Structured Cabling Purchasing Guidebook.
Editor's Note: This post was originally published in October, 2017 and has been updated for freshness, accuracy, and comprehensiveness.