Don't Get In Deep Water
As a follow-up to the blog on the reasons why UTP cables should not be painted, let's talk about cables that have been exposed to water or other liquids.
While the jacketing on indoor riser- and plenum-rated UTP cables may seem impervious to liquids, let me remind you again that it is actually porous. In fact, any cable rated for indoor use only, whether copper or fiber, should not be exposed to liquids for any length of time.
Let’s take a look at why.
Wicked Wicking
Once liquid initially penetrates the porous cable jacket, it is drawn further along the length of the cable, much like the wick of a candle. This wicking process is a no-win scenario.
Efforts to dry out cables can actually push the moisture further along the length of the cable. Removing the portion that was exposed to the liquid can also be a futile effort as it is not possible to estimate the length to which the wicking has occurred, and the water can travel through the cable much faster than you might think.
Cutting and examining the cable to determine if any liquid has penetrated to that point is also ill advised. The amount of liquid may be small and unnoticeable, or it may have already moved past the cut point.
If any liquid migrates to the copper conductors of a cable, it can cause corrosion that rapidly degrades the performance of the cable. Water within fiber cables can expand and contract with temperature change, potentially causing fiber breakage. That’s why cables that are exposed to water and other liquids will not be covered by Belden’s 25-year system warranty or component-level warranty.
Unfortunately, the only way to remedy the situation is to remove or replace any cable runs that have been exposed to liquids.
Know Your Environment
What if the cable will be deployed in an environment that you know has a higher potential for exposure to water or liquid, such as food preparation areas, locker rooms or any area that undergoes washdown or is subject to periodic flooding?
If liquid exposure is anticipated at any time, it is highly recommended to select cables of suitable construction for deployment in wet locations. The cable jacket itself is really the first line of defense, and there are specific types to consider. For example, look for gel-filled cables, waterblocking agents and low-density polyethylene jackets that provide moisture protection. Belden offers several varieties of cables with these design elements.
If an environment is truly considered harsh and will be subject to ongoing exposure to liquid, it’s more than just the cable itself you need to worry about.
The International Electrotechnical Commission (IEC) classifieds the degrees of protection provided by enclosures of a system, including boxes, outlets and even connectors. The Ingress Protection (IP) rating system is used to determine the protection against solid foreign objects and the ingress of water. As shown in the tables, the first number of the rating indicates protection against foreign objects, and the second indicates protection against water.
It’s always important to know your environment. And if it appears to be anything but a standard dry indoor area, contact Belden technical support to help you determine the right cable and connectivity for the job.
About the Author
Greg Funk began his career in 1984 as a distributed computer network analyst. Serving Belden for more than two decades, Greg was one of Belden’s data center experts and a recognized speaker at industry seminars and events. He fulfilled a variety of functions and was a field application engineer providing network engineering sales support in his region.