Talk:19-inch rack

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Mixing racks[edit]

Do not mix ETSI 500 mm wide rack (515 mm between mounting holes) with 23 inch rack. —Preceding unsigned comment added by (talk) 14:36, 20 September 2010 (UTC)

Rack Nuts are not standard[edit]

I don't know why the article says "The next innovation in rack design has been the square-hole rack. Square-hole racks allow boltless mounting, such that the rack-mount equipment only needs to insert through and hook down into the lip of the square hole. Installation and removal of hardware in a square hole rack is very easy and boltless, where the weight of the equipment and small retention clips are all that is necessary to hold the equipment in place."

In my experience captive rack nuts are not the standard and they are a pain in the ass to remove and install. Rack nuts are cheaper for the vendors so they can make more profit, they are not an innovation. —Preceding unsigned comment added by (talk) 09:50, 9 January 2010 (UTC)

- I think there are problems with this section, but both the article as it's written, and the comment above, are inaccurate. The square-hole racks did arise in an effort to make these racks both cheaper to make (stamping the square holes is cheaper than threading the rails) and more convenient (hanging rails with integrated clips is easier and faster than using screws). Non-threaded round-hole racks were never a standard, though they popped up from time to time. Cage nuts are conversion tools so equipment without clip-on rails can be used in square-hole racks, and by no means make anything cheaper.

What would be a useful contribution would be to determine where the square-hole pattern originated. I suspect it was originally a de-facto standard that later received the stamp from standards bodies. —Preceding unsigned comment added by (talk) 00:36, 9 March 2010 (UTC)

Center to Center Hole Spacing[edit]

The article says:

"each hole is part of a horizontal pair with a centre-to-centre distance of 18.3 inches (464.8 mm)."

which I assume must be correct. However, according to my calculations that means they are not quite in the middle of the 0.625" vertical mounting rails, which seems strange. I wonder why tenths of an inch would be used for this measurement when all the others are multiples of one eighth of an inch?

  • Center to Center mounting holes are Nineteen Inches...Hence a Nineteen inch rack industry standard for mounting nineteen inch rack mount equipment.

Regards, Scotty

No - the original comment was correct - screw centre to centre is 18.3 inches. The panels on the equipment, which extand to the edge of the rack-mount rails, are 19 inches wide. --Nineworlds 12:24, 16 January 2006 (UTC)
That's correct, gap from the inside edge of the rails is 17.75 inches (your computer or other equipment must be narrower than this), centerline to centerline, the holes are 18.25 inches apart, and width of the front plate for your equipment can be up to 19 inches. Most rack mounted equipment is a fraction under 17.75 wide and has 0.75 inch "ears" on the front making the width of the front a fraction under 19 inches.
I have no idea why the wikipedia article says 18.3 inches, can someone cite a standard that uses either 18.25 or 18.3? 18.25 makes more sense to me as this is a really old standard from the days when people used fractions of an inch and not decimal values. My equipment seems to be 18.25 inches on the button but I suspect I can't eyeball an 0.05 inch difference. Marc Kupper (talk) (contribs) 21:23, 1 September 2007 (UTC)
EIA-310-D, which is now in metric units, specifies the horizontal hole spacing center-to-center as 465mm (figure 3, page 4), which is 18.307 inches. The tolerance is 0.8mm, or 0.031 inches. jhawkinson (talk) 01:06, 2 June 2009 (UTC)

Article too specific[edit]

The following discussion is closed. Please do not modify it. Subsequent comments should be made in a new section. A summary of the conclusions reached follows.

The article is too specific because it describes a certain size. Consider renaming it Rack server.Jupiter.solarsyst.comm.arm.milk.universe 19:31, 14 June 2009 (UTC)

There are a lot of things besides servers that are rack mounted, so I'd say that's a bad idea. (And 19" is the most common form factor after all.) If there is a need for a more specific article about rack mounted servers then I'm all for creating it, but there should still be an article about the 19 inch standard. -- magetoo 11:54, 15 June 2009 (UTC)
It would sound like a flat rack 19 inches across for a casual user. And it is TOO SPECIFIC!!! Jupiter.solarsyst.comm.arm.milk.universe 02:07, 27 June 2009 (UTC)
The article is only too specific in that it is oriented so much to computers when 19-inch racks were in use long before computer servers were conceived and are still used for many different industries. However, the 23-inch rack article is practically orphaned. Both should be a part of an "Electronic Equipment Rack" article describing the 19-inch and 23-inch rack standards, the history, styles, and (briefly) the various common uses. Interestingly this article was previously redirected from one called "Equipment Rack." -Tim D. (talk) 23:31, 8 September 2009 (UTC)
Agreed. May change the template over there. Jupiter.solarsyst.comm.arm.milk.universe 23:57, 13 September 2009 (UTC)
Continuation of Talk:23-inch rack. Jupiter.solarsyst.comm.arm.milk.universe 00:03, 14 September 2009 (UTC)

The above discussion is closed. Please do not modify it. Subsequent comments should be made in a new section.

What just computers?[edit]

It is probably worth mentioning that computers are not the only items of kit that are rack mounted, perhaps one of the photos should be a radio studio or similar? —Preceding unsigned comment added by (talk) 17:04, 19 June 2009 (UTC)


The following comment was moved back from the archive page. jhawkinson (talk) 17:37, 31 July 2009 (UTC)

I tagged as dubious the assertion that "In all cases, especially with two-post racks, the rack must be secured to the floor or adjacent building structure so as to not fall over." on 20 May. recently added a comment to say, "Presumably this refers only to the US so it's not "In all cases"", but even that is not true. It's certainlu not true in the US that racks must be secured. Though it's probably a good idea for two-post relay-racks. I'm moving his comment to this talk page (here), and removing it. jhawkinson (talk) 00:59, 2 June 2009 (UTC)

I've just seen jhawkinson's comment about anchoring in archives 2. I agree with him - this statement is IMHO not only dubious but factually incorrect. It appears to originate in a false assumption, namely that all racks are ~40U behemoths. I have a rack here that is not only not anchored but actually on castors: it was supplied like that by the vendor. It makes perfect sense for a 12U under-desk pedestal unit. Similarly are we suggesting that the mobile DJ who brings a 6U portable rack enclosure is breaking any rules because his equipment is not secured in any manner? There may well be a grain of truth somewhere in this statement but it needs isolating and clarifying instead of asserting a patently wrong broad-brush generalisation. The always—especially disjunction does not help things either. If something is "always" the case then "especially" does not come into play. CrispMuncher (talk) 21:51, 30 June 2009 (UTC)

I concur. Many racks are not anchored and are not required to be anchored. The paragrph should be edited. -Tim D. (talk) 22:37, 8 September 2009 (UTC)

I'm going to go ahead and edit. Even if it were true, "must" is a bit vague here, as it doesn't say whether this is a legal requirement, if so what jurisdiction, or is it a requirement of the spec, or a physical requirement. Please take a look. Rees11 (talk) 17:15, 12 September 2009 (UTC)

As a side note, it is a BICSI requirement for two-post racks and similar that need to be secured in order to prevent tipping. Obviously, this does not include racks designed for castors or portability. The portable racks I have seen are normally mounted in a carrying case which would prevent tipping anyway, but certainly the larger, flimsier racks require securing to at least the floor, if not also to a wall or the ceiling, often using the cable tray. Occasionally, as in the case of the US DoD's WIN-T program's equipment, even the portable racks carry a tipping hazard and must be stacked in a particular order to reduce the risk.dunerat (talk) 09:19, 19 October 2010 (UTC)

Horizontal screw holes pitch[edit]

The article says :

each hole is part of a horizontal pair with a center-to-center distance of 18.3 inches (464.82 mm)

This is almost certainly wrong :

My guess is that the original (pre-metric) spec was 18-5/16" = 18.3125" ≈ 465.1 mm (talk) 08:25, 23 July 2009 (UTC)

310D says "465" mm and is toleranced at +/- 1.6 mm. There was a loss of precision in many places in this spec when it was "soft converted" to metric units from 310C. I don't have a copy of 310C to check your 5/16 theory against, but that seems plausible. The current text of the main article is telling us that 18.3inches is 464.82mm, which is not inherently wrong, but makes an error of precision, since 3 significant figures in inches should give us 3 significant figures in metric units. I will change it now. jhawkinson (talk) 03:02, 31 July 2009 (UTC)


Please stop aggressively archiving. We should not be repeating discussions that have taken place already in the archives. I've just moved some pertinent stuff back out. jhawkinson (talk) 17:37, 31 July 2009 (UTC)

Advertising web site in Wiki?[edit]

Can someone tell me if it is appropriate to place a URL in the article that links to a web page selling equipment? It doesn't seem to offer any information to the reader. Should it be removed? See: Overview and History section, URL . Mateck (talk) 03:33, 6 August 2009 (UTC)

Advertising in Wikipedia is never acceptable. The raw inline link we currently have is terrible. It should be removed. —fudoreaper (talk) 05:25, 6 August 2009 (UTC)

Advertising images[edit]

Advertising is not acceptable as per Wikipedia policy, yet 3 out of 4 photos illustrating the article show 19 inch systems from the same manufacturer, prominently displaying their logo on every single device (and the racks themselves), and even in the desktop wallpaper of the monitor shown. The author of all three is an employee of that company (which is again mentioned in the image credits). This is blatant advertising and makes it look like that manufacturer had a monopoly in this area. These photos should urgently be replaced with images showing not only the diversity of rack styles, but also the broad spectrum of typical 19-inch system usage (like telecommunications, sound recording studios, radio and television equipment, railway control systems etc. etc.) (talk) 07:39, 29 August 2009 (UTC)

The solution is to upload other images that show the same concept, and replace one or two of the other images. Binksternet (talk) 15:17, 29 August 2009 (UTC)

Conversion template[edit]

I'm usually a big proponent of the convert template but in this case, if EIA-310 gives metric values, I think we should use those exact values rather than a convert template. Otherwise we risk giving a number that is directly contradicted by our sources. Rees11 (talk) 12:57, 23 December 2009 (UTC)

I support this statement whole-heartedly. Then, one day, the ICT industry may catch up with the rest of the world by using ISO measures, including mm. Richardh9935 (talk) 23:28, 16 August 2013 (UTC)

Table of dimensions[edit]

I came here looking for a table of heights for 1U, 2U, 3U ...

Panel height in U inches mm
1U 1.719 43.7
2U 3.469 88.1
3U 5.219 132.6
4U 6.969 177.0
5U 8.719 221.4
6U 10.469 265.9
7U 12.219 310.3
8U 13.969 354.8
9U 15.719 399.3
10U 17.469 443.7

I made that to share - there may be a more precise one in the linked standards ? -- (talk) 04:40, 8 November 2010 (UTC)

We would need to find a standard to reference or a reliable secondary source. The problem is that there does not seem to be a standard for the panel heights. For example, the height of the panels you listed seem to have been computed by taking the height in units times 1.75 (inches) and subtracting 0.031 inches.
Panel = (Units * 1.75) - 0.31
  • surfixinc says they use an 0.03 inch clearance rather than 0.031 inches and the table on their web page confirms this.
  • hellermanntyton, middleatlantic, and video-furn do not have any clearance at all and do not use round holes. It's possible all of these panels are from one OEM.
I also saw that while most panels are flat some, such as this have a folded back lip on the top/bottom. Presumably that'll keep the panel from bending or flexing if it gets caught on equipment immediately above or below the panel.
Some people use 19" wide sheets of plastic and they cut the height to fit as needed. I suspect this also makes sense in that sometimes someone will mount something off center (not on a unit boundary) and/or a piece of equipment does not start/end on a unit boundary. Here or this) is a plastic panel that is pre-scored on 1U boundaries.
The other option drifts into WP:OR in that we would need to point out, as I did on this talk page, that there is little consistency among panel manufacturers. --Marc Kupper|talk 23:54, 24 June 2012 (UTC)


Alright, so someone has cleverly redirected subrack to this article, but the article contains no information how this is defined. Thyl Engelhardt213.70.217.172 (talk) 13:52, 20 June 2011 (UTC)

10 inch rack[edit]

What about 10 inch rack, or 12 inch rack?. Are any of them standard?. Do they have a technical name?. There's no mention of them anywhere. — Preceding unsigned comment added by (talk) 15:28, 23 July 2012 (UTC)

Merger complete[edit]

  YesY Merger complete All information from 23-inch rack has been merged into this article. Northamerica1000(talk) 11:06, 24 September 2012 (UTC)

Tapped Hole Thread Size[edit]

The article says:

"Holes so arranged can either be tapped (usually 1⁄4-inch UNC thread, more seldom metric 5 or 6 mm) or square. The square holes are meant for cage nuts. Tapped holes are more common in USA whereas square holes for cage nuts are common in Europe, especially in German cabinetry.[dubious ]"

Although I do not qualify as a professional user, I have purchased a wide variety of racks and rack mount equipment, both new and used, over the last forty-five years and I have never seen a tapped hole 19" rack in the USA that did not have 10-32 UNF threads. I have just put a caliper on ten different pieces of rack computer and audio equipment and the front panel holes in eight of the ten are less than 0.25" high, so could not accommodate a 1/4-20 mounting screw.

In support, I cite the Middle Atlantic Products catalog, which lists rack rail tapped 10-32 as well as half a dozen different styles of 10-32 screws. They also sell one style each of 12-24 and 6mm screws and cage nuts in both 10-32 and 6mm, but nothing in 1/4-20. . . Jim - Jameslwoodward (talk to mecontribs) 15:41, 14 November 2012 (UTC)

47U racks[edit]

We are starting to see 47U racks pretty often. Article doesn't mention them. — Preceding unsigned comment added by (talk) 21:13, 17 February 2014 (UTC)

Rack sizing[edit]

Came to the article hoping to get information on sizing, since I'm not familiar with racks. Article isn't clear. The rack that I'm looking at has the following:

  • 17 3/4" inside edges
  • 18 1/4" hole-to-hole
  • 20 1/2" outside edges

Nowhere do I see 19".  :) Not sure if this rack is non-standard size, or if the name "19 inch rack" is an approximation. Would be nice if the article introduction mentioned where the "19 inch" is to be measured. --Stéphane Charette (talk) 19:27, 4 March 2015 (UTC)