Cat6 Cable: Shielded vs. Unshielded

June 16, 2016 at 8:00 AM

 

When you need speed, Category 6 (Cat6) Ethernet cable is up to the task. Designed to provide Ethernet transmission speeds up to 1 Gbps, Cat6 is made to perform.

 

But how do you know whether to use shielded or unshielded Cat6 cable? We’ll help you answer that question and ensure that your network will perform optimally.

 

Deciding to use unshielded twisted pair (UTP) cable or shielded twisted pair (STP) cable is largely based on your application. The electrical environment surrounding your installation area is the most significant factor to consider. In some cases, cables experience slower transmission speeds and more data transmission errors when they are close to machines, power cables or other electronics that produce high electromagnetic or radio frequency interference (EMI/RFI).

 

By design, unshielded Cat6 cable provides some resistance to EMI/RFI due to the twisting of the wire pairs. Additionally, running a UTP cable at a 90-degree angle in relation to the source of the interference provides additional protection and minimizes exposure.  With its built-in protection (twisted pairs) and this additional safeguard, UTP Cat6 cabling can provide some protection from EMI/RFI.

 

If your application requires more protection from electromagnetic interference, shielded Cat6  may be the way to go. Shielding will protect your data from electromagnetic and radio interference, resulting in faster transmission speeds and fewer data errors.  Shielded cable is also better than unshielded cable at protecting from alien crosstalk (AXT).

 

When using shielded cable, the shield itself must have a drain to keep EMI/RFI from building-up and degrading the signal inside the cable. Draining is usually done at the connection site with a shielded coupler or jack connected to the ground.  It is also important to keep in mind that shielded cable is heavier than unshielded cable and, over time, may cause collapses and structural damage when running multiple cables.

 

Having a good understanding of your installation site will ultimately be the deciding factor when comparing shielded versus unshielded Cat6 Ethernet cable. In many cases, UTP comes out victorious over STP, except in areas of high EMI/RFI interference. Unless you’re running cable close to strong power lines, motors, magnets or radio antennas, it is likely that STP won’t improve your signal.  

 

Cabling for LAN and Premise Architecture

July 31, 2013 at 10:00 AM

 

Diagram of Wiring Closet Rack

It's hard to fathom just how quickly Ethernet technology has grown. Today no modern office building would be functional without premise wiring, or the cabling run throughout the building to connect computers to the LAN.

 

We may be on the verge of a wireless revolution with new technologies like DAS and MESH, but for now you should at least understand the basic architecture of LAN cabling.

 

LAN wiring is often broken into three types: backbone, horizontal runs, and patch cabling, each with its own purpose and requirements. In an especially large building or in a campus of buildings, the backbone is the wiring that connects server locations together and to the Internet through an ISP. Since a large amount of data may be carried back and forth by these cables, they are typically designed for bandwidth, like T1 lines or fiber optic cables (usually multi-fiber lines like breakout or distribution style, or even ribbon fibers).

 

Close Up View of Solid Conductor Category-rated Cable

The horizontal runs are the individual cables coming from the servers to the Work Areas. Work Areas are the points where the cable is terminated in a wall plate or jack so a user can plug their computer or other device into it.

 

It is often deceptive to assume that a single horizontal run will connect to a single computer. More likely than not, it is connected into a local Ethernet switch or wireless access point, and many computers may be connected to that. For this reason, the actual data carried on a single horizontal cable could vary greatly, and if you are planning your LAN architecture, this is the trickiest thing to get right. It can also be the most expensive piece to change if you get it wrong as you may need to fish the cable back out of a wall or conduit to re-arrange it.

 

Horizontal runs are currently most often solid-conductor Category rated copper cable. This is slowly changing over to fiber optic cabling as the price gap between the two narrows and fiber optic technology improves. Note that the horizontal cable may also require special jacket types to comply with building fire codes.

 

Right Angle Ethernet Cable Assembly

The patch cabling in a LAN is often overlooked, but is also very important. In general it is used to connect two devices together in a rack in a server room, or to connect a device to a wall jack where a horizontal cable is terminated. Being exposed (not behind a wall or on a rack ladder) and possibly being moved frequently, a patch cable needs to be robust and flexible.

 

While patch cables are easily available and can be bought relatively cheap, you might want to consider that cheap cables may introduce problems to your LAN. Cheap cables often use substitute materials such as copper clad aluminum or feature low quality plugs not rated for the application. Cheap cables seldom pass the testing required for the network and will degrade your network performance.

 

With more devices requiring power (POE), the cheaper cables often cannot carry the added burden due to undersized conductors and low grade copper. For a single user's computer, the impact of this may be limited, but in a server room low quality cables can have a disastrous effect on the entire LAN. If the cable manufacturer you purchase from has a robust QC process, it will help.

 

Other features to consider are molded right angle connectors to ensure the connector isn't bent to fit into limited space, cable boots to make depressing the connector latch easier, and high-flex construction and oil resistant jackets for demanding environments.

 

L-com stocks components for every facet of your LAN, from Ethernet cables, plugs and jacks, to bulk copper or fiber cable, to active media converters. We also go beyond that, to reliable racks, panels and cable management accessories, lightning and surge protectors, Power-over-Ethernet components and everything for wireless deployment.

 

Cat 6 Shielded vs. Unshielded

June 5, 2013 at 10:00 AM


Category 6 cable with drain wire

Category 6 or Cat6 Ethernet cable is designed to provide up to 1 Gbps Ethernet transmission, and is required for 1000 Base-T style networks. However, the choice to use unshielded twisted pairs (UTP) or shielded (or screened) twisted pairs (STP or ScTP) depends on the location of the installation.

 

Typically, the shield is only required in cases where the cable is run through an area of high electro-magnetic interference or radio frequency interference (EMI/RFI), such as output by strong power lines, motors, magnets, and radio antennas. Outside of these situations, the shield does not help provide a faster or clearer signal, and can add more problems than it solves.

 

Pros and cons 

 

Without a shield, Cat 6 UTP cable is already resistant to minor and typical forms of EMI/RFI, such as having a fluorescent light or small motor nearby. In these cases, you should always run the cable at a 90° angle to the source of the interference in order to minimize exposure. Otherwise UTP is cheaper, lighter, and just as effective as STP.

 

If you need STP cable, you have to remember that the shield itself must drain, otherwise EMI/RFI can build up on it and degrade the signal inside. Drainage is typically done at the connection site by using a shielded coupler or jack that is connected to ground.

 

Also note that the weight of shielded cable, while not very heavy, can be significant if you are running multiple cables in an area. In some cases, heavy cabling run above a ceiling or behind a wall has caused collapses and structural damage over time.

 

Quick note: Visit L-com's Ethernet Product Center for a huge selection of common and hard-to-find Ethernet cabling solutions, including shielded, harsh-environment, special jacketed and more.
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