How to Choose Correct Server Rails

In this post we will try to help you to choose correct server rails for your case

So you have decided to build your own server case. OK..that is just the first part of the journey. Now how do you actually mount it into your rack. That is a question which we will try to answer for you.

19-inch rack standard

First of all it would be good to know something about 19-inch server racks. We will not bother you with exhausting details and will try to keep it short and simple. This will help you down the road.

A 19-inch server rack standard refers to the standardized dimensions and specifications for mounting hardware, primarily used to house servers and other networking equipment. The term “19-inch” originates from the width of the racks, which are typically 19 inches wide between the vertical mounting rails. This standard allows for compatibility among a wide range of equipment from different manufacturers.

There are many various sub-standards, but the most commonly used which SLIGER server cases are based upon are:

• Electronic Industries Alliance EIA-310-D
• International Electrotechnical Commission IEC 60297-1 / IEC 60297-3-100
• Consumer Electronics Association CEA-310-E
• Deutsches Institut für Normung DIN 41494

Below are the standardized drawings of a rack post spacing.

Source: https://www.purestorage.com/nl/knowledge/definitive-guide-to-19-inch-server-rack-sizes.html

The most important information for the installation of the server case is the depth of the server case itself, depth of your rack and the inner width of the rack post spacing.

To make it simple, all Promark and General Devices server rails that we offer are compatible with all SLIGER server cases.

Beside the rail kits we offer, all SLIGER cases are compatible with General Devices C300-S Series rails and also brands such as iStarUSA TC Rails are natively compatible.

So in theory you could fit a 14inch long server rails onto a 25in deep SLIGER server case, but it would not make much sense, would it.

Checklist:

1. Check your rack depth
2. Choose the desired case – ideally not deeper than the rack to prevent case sticking out in the back
3. Check the inner rack opening between left and right rack posts
4. Choose the appropriate rail type

Example:

You have a standard 19 inch rack. The rack is 25 inches deep between front and rear rack posts.

This means, that:

1. Your server case or IT equipment should not be deeper than 25 inches
2. Your server rails must cover distance of 25 inches

When you stumble upon our Standard Promark Rails or General Devices Rails, you will see something like this:

The description of the selected rail kits will give you all the necessary information:

General Devices Rackmount Rail KIT, 14in Rail Slide with extension, MIN 15in / MAX 31in

This means, that this kit GDRAIL-14XX is a 14in long sliding part with multiple fixed extensions for various depths. When assembled together, the minimum length of the rail kit is 15 inches and maximum can be 31 inches.

In simple terms, this particular rail kit would fit into a rack that is minimum 15 inches deep or maximum 31 inches deep.

So for our example rack with 25 inches depth this would be the right fit.

How far will the case slide out of the cabinet?

It is the rail slide length that dictates, how much you can slide the case out of the rack. In the above example the 14 inch long rail slide will slide up to 14 inches out of the rack.

What about the width of the rack?

This is also an important question. As you can see above, the inner width of the rack (where you put the actual server case in between the rack posts) must be 17 – ¾ in wide, which equals to 450.85mm. This is the MINIMUM inner opening (means equal or more).

In simple terms it means, that the server case with the rails mounted on its side walls cannot be wider than 450.85mm, or the other way around the server rack cannot have an inner opening narrower than 450.85mm

All SLIGER server cases have a total width of 432mm to accommodate the wide up to 360mm long AIO radiator cooler and some front panel connectors.

Our rail slides are heavy duty and have a thick construction. For most commonly used racks our Standard Promark Rails are perfectly suitable.

However recently we have noticed with some customers, that some rack cabinets had less than the 450,85mm minimum opening (less than the common 19in rack standard). Most of the observed problematic racks being at around 449-450mm (especially from manufacturer Startech). That leads to the rails not being able to slide out correctly.

Therefore, we always recommend measuring the inner rack post spacing. If it is too tight, then you could use a simple server shelf or you can use our General Devices Rails which are more narrow.

Below you will find also links to our installation guides which provide more details about mounting of the rails:

General Devices Rails Installation Manual

Promark Standard Rails Installation Manual

We hope that this article will help you choose the correct product with ease.

Warm regards,

Michal from DENSITY.sk

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