Interconnecting the various IT resources in a data center requires large amounts of cabling (whether fiber, copper or a combination of the two). Perhaps you have seen mess of wires and cables that can quickly build behind your desk, especially if you have a number of connected gadgets; the situation in the data center can be much worse if not carefully controlled. Finding a good place for cabling that permits good airflow, accessibility for maintenance and expansion, and safety (for personnel and equipment) is critical.
Benefits of Overhead Cabling
From an energy efficiency standpoint, overhead cabling eliminates one major source of airflow obstruction, helping reduce the likelihood of hot spots. According to an APC by Schneider Electric white paper (“How Overhead Cabling Saves Energy in Data Centers”), “The decision to place network data and power cabling into overhead cable trays can lower cooling fan and pump power consumption by 24%.”
But another major benefit is accessibility. Instead of being under the floor—and possibly all but inaccessible owing to the arrangement of equipment above the floor or the hassles of lifting floor tiles—overhead cabling can be entirely accessible, easing the process of maintaining existing cables or adding new ones. A TechTarget.com article (“Using overhead cables to tidy your data center: Ask the Expert podcast”) cites Robert McFarlane, a principal at consulting and technology design firm Shen Milsom and Wilke, as identifying another tremendous advantage: “avoiding the need to comply with article 645 of the National Electrical Code (NEC) and the dangerous Emergency Power Off (EPO) button that article requires.” The EPO button is a perennial source of headaches for data center operators: it has been mistaken for a variety of purposes, including a door opener, to the catastrophic detriment of data center uptime. Of course, McFarlane is referring to the use of overhead cabling for power cables in this context. But it is worth noting that the overhead cabling concept can also apply to power cables, delivering the same airflow and maintenance benefits on the facilities side as it does on the IT side.
Thus, if implemented properly, overhead cabling can improve both data center efficiency and uptime — a dual win. But the key is doing so in a way that avoids some common pitfalls.
