Electronics in the wiring closet

Just a few thoughts about switches and other electronics in your school wiring closets based on a district discussion I recently had:

* Check your environmental conditions – I know that some of you may not be able to immediately fix some of these problems, but it needs to be in your plans somewhere. If your wiring closet doubles as custodial storage, watch for the trend to use switches as a shelf for chemicals, etc. Some wiring racks double as a coat rack, which kills any hope of adequate ventilation. Switches today are more dense and, while it’s a great space-saver, it makes proper ventilation an even more important requirement. In some cases, it isn’t a coat covering the vents on a switch or server; rather, it’s a thick layer of dust. Much like straightening up your patch cables, cleaning out dust on switching electronics is one of those tasks that always seems to wait until a better time. Too much dust can equal no ventilation and no ventilation can lead to equipment failure, which leads me to…

* Check your temperature – Most of these network electronics prefer a cooler temperature than would a human occupant. Nevertheless, there are countless closets where no dedicated cooling is in place. This is particularly important in data centers where racks full of network components and servers may be installed. This is the time of year where a lack of dedicated cooling can really harm a school district. Why? The school’s HVAC system is heating the rest of the building and, in some cases, it’s actually heating the wiring closet or data center. In some cases, the effect is seen immediately. Servers today can (and will) shut themselves down if sensors indicate that the environment is too warm. Other components like switches and routers may not fail immediately, but these components will have a shorter lifespan if regularly exposed to excessive heat. Also, don’t forget about these electronics that may be left on while a cooling unit is shut down (for summer break, for example).

* Check your battery backup – Honestly, the bigger issue in many cases is that some outlying wiring closets don’t even have battery backups for switches and network electronics. For those that do, I’ve heard many reports on UPS devices failing quite often. The UPS battery is seen as a money pit. Why do they fail so often? If the environment is too hot, the UPS can be significantly degraded. In fact, according to this APC white paper, some batteries experience a 50% reduction in life for every 14.4 degree temperature increase over optimum, which is about 77 degrees. This paper also discusses the number of discharges and the rate of charging as factors in UPS life. There’s some good info in the white paper. The bottom line is to understand that proper battery backups are needed but that their life is impacted by the same factors as other network electronics.

At any rate, this was on my mind after meeting with a school district this week. Hope it’s of some interest – take care!

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