Guide for Cable Management in Rack Systems

Today’s high-density rack-based IT server and switching installations provide higher and higher levels of performance and capacity. But with this growth of capability, there come a parallel growth of discrete data communications and power cabling that must be managed within the confine of these tightly spaced rack environments. Improper cable management can result in cable damage and failure, which can lead to data transmission errors and performance issues as well as system downtime. This article will focus on the cable management in rack cabling systems.

Why Proper Cable Management Is Important?

Poor cable management can cause a series of network problems. The following are the common problems.

Signal interference and crosstalk due to improper placement of data and power cables—Data and power cables running close to each other in parallel groups or in loops may create electromagnetic interference (EMI) due to induction. EMI can cause errors in data transmission over these cables. Whenever possible, power cables should be isolated from data cables on opposite sides of the rack to reduce the chances of EMI.

Rack-mounted components blocked by improperly routed cables—Access to servers and other network components housed within an enclosure is critical. Due to the high-density of cabling in many of these applications, it is important that cabling does not block these components, racks or rails. Fiber optic cables present additional challenges because of the more fragile nature. Care should be taken to avoid having other cables or components exerting tension on the fiber cables to avoid damage. Cable ties can be used to secure fiber optic cables. Try not to route fiber optic cable around corners within the enclosure.

Cooling and airflow restriction resulting from poor cable placement—It is important to make sure that cables are not placed in such a way that they restrict airflow from components inside the enclosure. Obstructed air movement due to blocked vents and fans can result in component overheating and possible thermal shutdown or even equipment damage.

Cable Management in Server Cabinets

Data centers contain two basic types of equipment enclosures: server cabinets and network cabinets. This part will tell the cable management in server cabinets and the next part will tell management in network cabinets.

Server cabinets house mostly active equipment in the form of blade chassis or stackable servers. The first step of preparing cable management for the enclosure is to determine the capacity needed for cabling. Calculate the number and type of connections per server and the total number of servers expected to be housed in the cabinet and determine where the cable needs to be routed.

Cabling Requirements Unique to Server Cabinets

Server cabinets typically have the patching for the devices occupying the rear-facing portion of the cabinet, along with power connections. This requires management of both network and power cords. The copper connections and fiber connections are served from one vertical bay, while power connections are addressed form another bay.

A mounting area is provided where vertical mounted power strips are used. In instances where power and network cords have to cross from one side of the cabinet to the other, the use of horizontal cable managers can be deployed to provide distinct paths. Noted that power and network cords should be housed in separate cable managers. The ability to house these connections in the vertical patching space assures that cables are dressed in such a manner that they do not block exhaust fans on the rear of the servers.

Cable Management in Network Cabinets

Network cabinets house network switches and patch panels. These cabinets have the highest concentration of cabling in the data center, making patch cord management even more critical and requiring both horizontal and vertical cable management. Due to the high concentration of cabling in these cabinets, a typical installation would use 19” patch panels and standard fiber enclosures mounted either at the top of the switch cabinet or in some cases in an adjacent cabinet when the cabinet houses multiple switches.

Cabling Requirements Unique to Network Cabinets

The majority of the patching connections typically occur at the front of the cabinet. For in row switching or top of rack switching, the set back side rails populated with a horizontal cable managers allow patching within the cabinet and down the row.

Typically, the cabinets would be configured in a manner using rack mount patch panels and cable managers along with vertically mounted cable managers to provide pathways for patch cords transcending from top of rack patch panels to bottom of rack switches.

Tips for Specifying and Applying Cable Management Products

Start with proper planning—Once you have determined the amount of cabling and connections required, you can decide where the cables need to be routed within the cabinet. This will allow you to select the proper cable management components needed to properly secure the wiring and connections. It is important to make sure that there will be adequate space within the rack for the amount of cabling to be used. Accurately establishing the amount of cabling and connections needed ahead of deployment will greatly improve the chance of a successful installation.

Keep growth in mind—Growth in the data center environment is a certainty. Planning ahead for installing additional cabinets, servers and network components should be taken into consideration even as you are installing the first phase of your racks. This will make it easier to integrate additional racks and components in the future. Poor planning in terms of future changes can often result in the spaghetti of wiring present in many data centers.

Follow industry standards—Industry guidelines, such as ANSI/TIA and ISO/IEC, as well as any federal, state or local regulations regarding cabling should always be followed. This not only assures code compliance but promises a safe, failure-free installation that will minimize system downtime and data errors. A standards-based cabling system will provide the best combination of reliability today and the ability to change and reconfigure in the future. Standards provide a written foundation for establishing a sound infrastructure and guidelines for maintaining a high level of cable performance.

Summary

In a word, poor cable management can lead to additional cost and time, while proper management can reduce signal interference, improve maintenance ans serviceability. FS.COM provides a series of cable management products, such as cable manager, cable tie, etc., which are suitable for specific layout requirements and provide ideal solution for the distribution of cables and access to power, data and communication services.

This article originates from http://www.fs.com/blog/guide-for-cable-management-in-rack-systems.html