Simplifying the Many Differences among Ethernet Cables
If you Google “Ethernet cables” you’ll get about 5 million hits. It’s no wonder that shopping for Ethernet cables can be confusing. But if you simplify the cables down to their main differences, it’s much easier to choose the one that’s best for your use.
This blog post explains the chief differences among the cable categories. But instead of trying to cover everything from Cat1 to Cat8, we discuss only the four categories used most in office networks, data centers and residences: Cat5e, Cat6, Cat6a and Cat7. We conclude by clarifying some of the choices you might also have to make about cable jacketing types and their burn ratings.
In each Ethernet cable category below, we discuss the four most important features that delineate one category from another. The first is a cable’s maximum data rate, which is measured in megabits or gigabits per second. The second feature is the longest distance it can maintain that data rate. The third is a cable’s bandwidth (in megahertz), which basically determines how much data can be transferred at any one time. The fourth feature is whether or not the conductors are shielded − with unshielded cables being more flexible and thus easier to install, and shielded cables offering more protection against electromagnetic interference (EMI).
Cat5e cable is the minimum standard unshielded twisted pair cabling used for LAN drops. It is used in 100Base-T Ethernet. It has a bandwidth of 100 MHz. Its maximum data rate and distance are 1 Gbps at up to 100 meters, a big upgrade over the 100 Mbps rate of Cat5.
Cat6 With more stringent specs for cross talk and system noise than Cat5e, Cat6 cable is able to carry gigabit Ethernet in commercial buildings. It is also used for phone lines and in residences. It is available shielded or unshielded. It has a bandwidth of 250 MHz, and its data rate and distance are 1 Gbps at up to 100 meters and 10 Gbps at up to 37 meters.
Cat6a Shielded Cat6a is commonly used for gigabit Ethernet in data centers and commercial buildings. Its 500 MHz bandwidth is twice that of Cat6 and its data rate and distance are 10 Gbps all the way up to 100 meters. This increase in bandwidth capability involves the addition of shielded twisted pair cabling, which makes the cable heavier, more difficult to bend and up to 30% more expensive.
Cat7 Shielded Cat7 cable has the same data rate and distance specs of Cat6a (10 Gbps up to 100 meters) but it offers 100 MHz more bandwidth and costs about 20% more. It is used for 10 Gbps core infrastructure and is commonly found in data centers. Its performance is similar to Cat6a but it has proprietary GigaGate 45 connectors and tougher shielding. An improvement on Cat7 is Cat7a, with 1000 MHz bandwidth, 40 Gbps up to 50 meters and 100 Gbps up to 15 meters.
The type of cable jacket you need depends on where the cable will be located. Most Ethernet cables have a jacket made of PVC, the standard material for patch cords and risers (anything going into a wall but not a ceiling). Plenum jackets are required in the U.S. for anything going into an airspace (a space above a drop ceiling or below a raised floor) or horizontally into a building. An LSZH (low smoke zero halogen) jacket is used where electronics-destroying halogens are prohibited, because it emits less smoke than other jackets and is free of halogens. PUR (polyurethane) cable jackets are both tough and flexible, ideal for outdoor and industrial settings. PE (polyethylene) jackets are also used outdoors due to their low water absorption. FR-TPE jacketing is similar to PUR but with additional oil and chemical resistance. FEP (fluorinated ethylene propylene) is used mostly in the aerospace industry due to its very high temperature rating and its resistance to chemicals and oils.
An Ethernet cable’s jacketing determines its burn rating. When installing or using cables in walls, ceilings or otherwise as premise wiring, use materials that meet both local and international standards for flame and smoke resistance. These standards are generally governed by a nonprofit entity such as NEC, UL, IEC or CSA.
Following are the standard burn ratings, with CM abbreviating “communications multipurpose.” A CMP rating (CM plenum) is for in-wall, in-ceiling, plenum and riser applications. A CMR rating (CM riser) is for in-wall risers but not for plenums. Both CM and CMG (CM general) are in-wall rated only for one-family or two-family residences or in risers with raceways or fireproof shafts. CMX is for limited residential use.
We hope this has helped simplify your choices in selecting Ethernet cable. The category you choose depends largely on the cable’s data rate, the distance it can maintain that rate, the bandwidth you need, and whether you require shielding. Another consideration is cable jacketing, which depends on where your installation will be located as well as established standards.
Shopping for Ethernet products here at ShowMeCables means you have access to our inventory of more than 15,000 cables, connectors and installation products, most of which are in-stock and available for same-day shipping. To see our Ethernet cable selection, click here or call today at 1-888-519-9505 to speak to a sales representative.