Why Moisture and Internal Rated Communications Cable do not mix!

Steve Smitham from Molex discusses why Moisture and Internal rated Communications Cable do not mix!!

Over the years Steve has encountered the question many times ……

How will moisture ingress affect the performance of my data cabling?

There are a number of situations that will result in water ingress, but no matter the case, if the cable properties do not provide a moisture barrier and water comes into the picture the installation and network cable is in trouble.

Typical internal cable is built with PVC, (Polyvinyl Chloride), insulating material, with a jacket that is “airy” due to extrusion processes and essentially acts like a sponge. Any exposure to moisture will be taken up by the cable jacket and migrate to the cable pairs or fibre cores within.

If we focus on copper cabling this time around, how will moisture affect the cable performance? In many ways …….. Both mechanical and electrical.

During installation phase, depending on site situation, look out for potential exposure of the cable to moisture. Large or small installs, where construction of new single level or couple of floors are concerned, communications cabling can be installed at frame stage, before lock-up and sealed property is attained. This is prime problem area. The cable can still be exposed to the elements either by nature itself or from activities on the site. Sometimes time constraints on site call for the cable to be installed before ideal conditions are available, consider the situation on a site by site basis and avoid compromising the cable integrity. Nature isn’t predictable, large down pours, yet a part of the cable sitting in a puddle will be an issue. Even in CBD high rise installs with sealed floors, be conscious of potential problems.

Consultants, end-users and installers alike must be aware of these situations and program the install to get around such incidents. Point is, do not expose internal rated cable to the elements.

There have been instances where installed cable has been subjected to flood and full submersion to water. This has happened during install and during life cycle of the installed cable. Again this can be natural or man-made events. Even a short duration of cable submerged in water will affect the long term performance of the cable and no amount of “Hair Dryer” application will fix the situation.

In all cases for long term expectations of performance, internal rated cable exposed to moisture, must be replaced.

Page Data would like to thank Molex Premises networks for providing this information.  More information on the Molex product can be found at www.molexpn.com.au.