WHAT IS A RACK?

The term ‘rack cabinet’ is commonly used to define a method of installing devices in cabinets and to define the cabinets themselves. Specifications of network devices or sound equipment often include expressions such as “for rack cabinet mounting” or “installation in a rack cabinet”; this means that the device has mounting handles that allow you to place it in a ‘rack cabinet’.  However, we should note that there are several versions of mounting rail spacing in a rack cabinet, so not all devices can be installed in any rack cabinet. While small devices can usually be installed in a large rack cabinet using adapters, a big device simply cannot be squeezed into a small rack cabinet. Therefore, it is best to adapt the rack cabinet to the size of the devices to be installed. Apart from rack cabinet-mounted devices, a rack cabinet may be used to install desktop devices; in this case, we need to attach a shelf where such free-floor-standing devices can be placed.

WHAT ARE TYPICAL RACK SPACINGS?

The rail spacing is measured in inches, and the presently existing spacings are as follows:

  • 21” – (or just ETSI) used mainly in the systems maintained by telecommunication operators
  • 19” – a typical spacing used in most server rooms and data centres to install switches or servers
  • 10” – the smallest spacing, used in cabinets intended for home systems and in small enterprises

In this article, we focus on the latter standard.

10” RACK: HOW BIG IS IT AND WHAT CAN IT CONTAIN?

The 10” rack cabinet is a good solution when we must professionally terminate a cabling distribution point or build a small network at home or in a company. We should note that the rack cabinets in this standard are not only narrow (their overall width is 310 to 350mm) but also relatively shallow (with a normal overall depth of 280 to 300mm). It should be considered when choosing the equipment to be installed in the casing. While there should be no serious problem with switches, we should pay a great attention when selecting a monitoring recorder or a small server. For the latter device, in practice we can only choose the solutions in the smallest ITX casings such as D-150 by Emko Case.

Virtually no ITX mini casings, NASs or DVRs/NVRs are offered in versions installed in 10” rack cabinet casings, so in a cabinet we should place them on a shelf mounted to rack cabinet rails.

The height of a rack cabinet depends on its ‘capacity’ expressed in U. One U equals 1 ¾ inches so 4.445cm. The number of U units occupied by a patch panel, strip or switch is provided in the appropriate specification. The overall height of a rack cabinet is adequately larger so to ensure an appropriate space from top and bottom of the equipment installed.

EXAMPLE INSTALLATION OF DEVICES IN A 10” RACK

Przykładowa instalacja urządzeń w szafie rack 10"
Check the detailed specification of a STLWMC10C-9U-GSB cabinet.

PROS AND CONS OF 10” RACKS

An advantage of the 10” standard is certainly the little space required for installation. This makes it possible to professionally terminate the system also where there is no space dedicated for network equipment. An example can be flats, staircases, business premises, containers or other rooms where every inch makes a difference.

What is a disadvantage of these solutions?  Paradoxically, it is the same thing: while we save the outer space, there is little space inside. This forces us to carefully select the equipment and count every inch and U unit. Another thing is ventilation: in small rack cabinets, we cannot install devices emitting a strong heat, as ventilation is not as good as in 19” rack cabinets. Consequently, it is certainly not a good location for high-performance servers or multi-disk NASs, which is actually not a problem as they will not squeeze there anyway ;).

I hope I managed to explain the subject of 10” rack cabinets, and you will know what to choose when planning a network in a location where a large rack cabinet cannot be accommodated. On our websites, you will find a full specification of rack cabinets and related accessories.

At the end, we invite you to watch a video presenting our 10” rack cabinet system and accessories: