Shielded Ethernet Cable: Advantages and Disadvantages

November 18, 2013 at 9:08 AM

 

 

Cat5e Shielded Ethernet Cable- 26 AWG Stranded PVC Industrial Ethernet Patch Cords - Blue

Shielding Ethernet Data from EMI/RFI

 

The typical Ethernet cable has four twisted pairs terminated to the eight pins in the clipped "RJ-45" (also, more correctly known as 8p x 8c connector) at either end. The cable used is commonly called "UTP", which stands for unshielded twisted-pair.

  

If there is an unshielded version, there must also be a shielded version right? That is correct. Today we'll look at STP, or shielded twisted-pair

 


The Shielding Disadvantages

 

Shielding is not an automatic choice for every installation. Why? Because although shielding provides the protection that may be necessary for some environments, it also comes with some serious disadvantages.

Shielded Ethernet Cable

 

The first is weight. A single-shielded Ethernet cable weighs on average about 12% more than an unshielded cable, and a double-shielded Ethernet cable weighs as much as 30% more. That doesn't mean much when you have a single 4oz cable. But what if your building has dozens or maybe hundreds of individual STP cables that run on ladders over a ceiling, under a floor, or behind walls? The combined weight from these cables could be such that they actually damage the rack. 

 

The second disadvantage is flexibility. In permanent installs, this isn't so much of an issue, though you must be careful when pulling the cable through conduit. But in applications where the cable is attached to something moving, like a robotic arm, a swiveling camera, or tools used by manufacturing personnel, the shield can be a problem. A single foil shield can break and the sharp edges of the cut in the shield would grind against the insulation of the individual wires, eventually cutting into it and shorting it out. Your best bet is to get tight-extruded cables rated for continuous flexing to ensure the maximum lifespan over repeated cycling.

 

Shielding Options

 

There are several options available if you need a shielded cable for your Ethernet application:

 

 

© L-com, Inc. All Rights Reserved. L-com, Inc., 50 High Street, West Mill, Third Floor, Suite 30, MA 01845