10 Factors to consider when choosing a cabinet or rack

The sheer number and different types of cabinets and racks can make choosing the right one for your data center a daunting task. But, if you consider your requirements one at a time, you can zero in on the right cabinet or rack for your application.

A cabinet is an enclosure with four rails and a door (or doors) and side panels. A rack is an open, freestanding 2- or 4-post frame that doesn’t have doors or sides. The decision on whether to use a cabinet or rack depends on a number of factors.

1. Equipment data-center
Before you choose a cabinet or rack, you need to determine what equipment you’re planning to house. This list can include servers, switches, routers, and UPSs. Consider the weight of your equipment as well. The extra stability of a cabinet might be important if you’re installing large, heavy equipment like servers. An open rack is more convenient than a cabinet if you need frequent access to all sides of the equipment.

2. Environment
With the open design, racks are a good choice in areas where security isn’t a concern such as in locked data centers and closets. And racks typically cost less than cabinets.

Cabinets, on the other hand, protect equipment in open, dusty, and industrial environments. Aesthetics can be a factor too. Will customers or clients see your installation? A cabinet with a door looks much neater than an open rack. When you’re trying to create a professional image, everything counts.

3. Ventilation
If your equipment needs ventilation, a rack offers more air circulation than a cabinet. Even if your cabinet is in a climate-controlled room, the equipment in it can generate a lot of heat. The requirements for additional airflow increase as more servers are mounted in a cabinet. Options to improve airflow include doors, fans, and air conditioners.

4. Size
Width: The width between the rails in both cabinets and racks is 19 inches with hole-to-hole centers measuring 18.3 inches. But there are also cabinets and racks with 23-inch rails. Most rackmount equipment is made to fit 19-inch rails but can be adapted to fit wider rails.

Rack Units: One rack unit (RU or U) equals 1.75″ of vertical space on the rails. A device that’s 2U high takes up 3.5 inches of vertical rack space. Rack units are typically marked on the rails. The number of rack units determines how much equipment you can install.

Depth: Cabinets and four-post open racks come in different depths ranging anywhere from 24″ to 48″ to accommodate equipment of varying sizes, particularly extra-deep servers. The rails on some cabinets and 4-post open racks are also adjustable to different depths.

When you consider the width, height, and depth of a cabinet or rack, clarify whether they are inside or outside dimensions.

5. Weight
Cabinets and racks vary in terms of the amount of weight capacity. Some cabinets can hold 1,000 pounds or more. Carefully consider the weight of your equipment and decide where you want to mount it before choosing a cabinet or rack.

6. Rails
The vertical rails in cabinets and racks have holes for mounting equipment. Two post racks typically have threaded 12-24 or 10-32 tapped holes. 4-post racks and cabinets often have M6 square holes for mounting servers.

7. Moisture, dust, shock, vibration
When housing electronic components outside of a protected data center, look for a cabinet with a NEMA (National Manufacturers’ Association) rating. NEMA standards are designed for corrosion resistance, protection from rain, submersion, liquids, dust, falling objects, and other hazards. There are also NEBS-Telcordia standards for protection against seismic activity, shock, and vibration. Cabinets and racks can also be bolted to the floor for extra stability.

8. Power provisioning
There are multiple options for powering rackmounted equipment. Power strips mount can be mounted vertically or horizontally. Power Distribution Units (PDUs) and Power Managers have additional capabilities such as remote management and metering. Uninterruptible power supplies (UPSs) typically mount in the bottom of a cabinet or rack because of their weight.

9. Cable management
Most cabinets and racks have built-in cable management troughs and cable rings for routing cable. For more information on cable management, see 9 Ways to Improve Data Center Cable Management.

10. The extras
The type of shelving you choose depends on the equipment you plan to mount. There are multiple options: solid, vented, stationary, and pull-out shelves. And there are shelves built to hold specific pieces of equipment, such as servers or keyboards. Other extras include fans, waterfall brackets, and grounding bars.

9 Ways to improve data center cable management

Cable management is one of the most important aspects of data center design. Last week, Processor magazine interviewed our Wire and Cable Product Engineer, Steve Molek, on ways to improve data center cable management. Below is the transcript from that interview.

Processor: Do you feel data centers have made inroads in recent years in terms of cable management, neatness, and organization? If so, what do you attribute the improvement to?

Steve: Yes. Equipment overall has become smaller, thus allowing more electronics in a cabinet.  Because of this, installers must pay closer attention to cable management, otherwise they can lose the valuable space gained to the additional cables.

Processor: In what areas do data centers still falter in terms of cable management? Where can they still improve?

Steve: Old habits die hard. In the past, cable management was not a focus, since data centers used a more “centralized design.” Today, cable management should follow a more structured design, similar to horizontal cable runs.

Also, one of the simplest ways to organize your data center is by using colored patch cables and bulk cables. Colored cable has been around a long time, and coloring the security system differently from accounting or customer service lines, for example, is a great way to visually identify different runs of cable at a glance. We offer the same kind of coloring in our fiber patch cable lines as well, which is not as common in the industry. Continue reading

Cable management: Overhead or underfloor system?

One of the biggest considerations is whether you’re going to use an overhead cable management system, such as basket trays and ladder racks, or an underfloor system. This affects what you buy, how you install it, etc. A number of factors determine which system to choose.

One of the most important is budget. If your budget is tight, an overhead system is the better option. It’s less expensive to buy and much less expensive to install. Also, plenum cables may be required in an underfloor system. In an overhead system where the cabling is installed below the ceiling grade, plenum cables are not required. This results in cost savings.

Next is the size of the room and the cabinets. TIA-942 mandates a minimum ceiling height of 8.5 feet above the finished floor to allow for 7-foot racks and cabinets. In addition, TIA-942 also mandates a clearance of 18 inches above the cable pathways for sprinklers, etc. This could limit overhead cabling in low-ceiling rooms. Don’t forget to measure the cabinet heights as well to allow for these clearances. Also, if there are different size cabinets, you must be take that into consideration as well. If you have different height cabinets, you’ll have to design around that.

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Three Essential firestopping tips

Most cables are constructed with standard polymer jackets, which are combustible. Copper and aluminum are the most common metals used as conductors. Unfortunately, they’re good conductors of heat. The conductors can spread a fire by igniting surrounding flammable materials, such as the cable jacket. Then the jacket burns away, the conductors melt together, and the size of the cable bundle shrinks and causes gaps to develop within the cabling opening. This can be a major fire risk.

Firestopping is a term used to describe sealing and protecting openings and other joints between the cable and edges of the floor, wall, or ceiling. Firestopping was first practiced on U.S. combat ships in the 1960s. The walls and floors of the ships had steel tubes, which allowed conduits to pass through. Then, non-burning material was stuffed between the gaps, preventing the spread of fire and smoke. It wasn’t until the 1970s when larger companies began producing firestopping materials.

A successful firestop plan requires careful planning. Here are three tips to help you meet the needs of future cabling requirements and fire protection:

#1. Think long term
Most people tend to underestimate the size of the openings required for cabling and often forget about future expansion. When planning on how large to make the opening to run your cable, you must consider the diameter of the cable itself, how much room you need for firestopping materials, and whether you’ll be adding more cables in the future.

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The best accessories for your IT cabinet

Once you’ve chosen your cabinet, whether it be customized Elite or an energy-saving ClimateCab, it’s time to add accessories for even more function.

Cabinets have two sets of rails, front and back, where you can mount shelves, trays, cable managers, and power strips.

Shelves
Cabinet shelves are an easy solution for storing things that aren’t rackmountable. The shelves attach to the rails; servers or other equipment sits on the shelves. Make sure the shelf has the weight capacity you need—some can hold hundreds of pounds. For easy access to components in your cabinet, choose a sliding shelf. There are also vented shelves that improve air circulation within the cabinet.

Although most shelves fit 19” rails, there are shelves that go on the less-common 23” rails. There are also brackets that can adapt many devices intended for 19” mount to 23” rails.

Keyboard Trays
Keyboard trays are space-saving solutions that also keep your data center organized. They slide neatly into your cabinet or rack—and out of your way—when not in use. And they usually fit into only 1U of rack space.

KVM Trays
Further reduce clutter in your server room by using KVM trays that are 1-or 2U high mounted in your cabinet. Special features of many KVM trays include rock-solid construction, LEDs on the front panel for easy location in a darkened data center, and integrated KVM switching.

Front-panel controls enable you to use the buttons on a monitor bezel without pulling out the keyboard. Some trays have USB ports for access.

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