Bigger Isn’t Always Better – Be Mindful of the Category Rating

More and more of our projects involve networked systems and associated devices, and that inevitably includes cabling. And, as the price differential between the various category-rated cables diminishes, we are finding the temptation to provide the highest level of category rating possible throughout projects, whether or not it makes sense. If CAT5 is good, and CAT5e is better, isn’t CAT6 best? Shouldn’t we just play it safe and use it everywhere? Not necessarily.

When doing work for the U.S. Postal Service several years ago, we explored this question. Its inclination was to use CAT6 everywhere to make its networks consistent. But the capability of CAT5e far exceeds the bandwidth requirements of an IP camera by a factor of 200, so we recommended against it. At the time, the savings was about $100 a box and could easily add up. We also felt that the ease of pulling CAT5e cable was a factor; it is thinner, easier to work with, and more flexible for the most part. To be honest, I’m not sure whether or not the USPS took our recommendation, but a number of other clients have, and we continue to recommend CAT5e for devices that consume limited bandwidth and are connected to a backbone that will allow expansion.

But head end wiring has always been different for us. We have long recommended CAT6 for rack wiring, even though the connected equipment doesn’t consume that level of bandwidth. The cost difference is not material, and we believe that it makes the system more “future proof”. But a recent trip to a jobsite has made me question that philosophy and we’ll be thinking about that in the months ahead as we move forward with several new projects.

For one, the future proof argument doesn’t really apply. It is extremely simple to pull a new cable within a rack room, so if CAT6 was ever needed, it would be nothing to put it in. In fact, that argument speaks more to the field devices, where it would be difficult to re-pull cable. While we are still confident that CAT5e is sufficient for most of these cases, we will continue to review each application and make sure we’re covering all contingencies.

But the second argument for higher performance cabling is “why not?” If the cost isn’t a factor and it will work as well, why not go with the gold standard? And, until recently, I couldn’t come up with a reason for using CAT5 in a rack room, or for patch cables and short equipment interconnections as well. But a project in a high end mall in the San Diego area that was plagued with reliability problems after a rack was re-wired brought me a surprising answer.

CAT6 cables and patch cords are inherently stiffer than CAT5e cables. While this may not make a difference everywhere, the bend radiuses in this rack were exerting off-axis pressure on the cables. This meant that connections were pushed up, sown, or to the side by the force of the cabling and there were reliability problems with the associated connections. Sure, if you want to let your rack wiring look like spaghetti, it is less of a problem, but we admittedly have a thing for nice, neat installations, and replacement of the patch cords with more flexible CAT5e cables solved reliability problems immediately, while maintaining a professional appearance.

So, in that continuing quest for self improvement, we are looking at an area that we thought was done and settled years ago. It reminds us that our mission is better served when we add the word “appropriately” to the end of it. As consultants, integrators, manufacturers or end users working in any technology field, we solve problems by applying the latest technology — appropriately.

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