The size denotes the width of the faceplate for the installed equipment.
19 inch rack hole spacing.
The rack or cabinet must meet the eia standard eia 310 d for 19 inch racks.
Such a region is commonly known as an ru or u for rack unit or unit.
Nothing on a 19 rack measures 19 inches.
1u occupies 1 75 inches 44 45 mm of vertical space.
The rack unit is a measure of vertical spacing and is common to both the 19 and 23 inch racks.
Do not mix etsi 500 mm wide rack 515 mm between mounting holes with 23 inch rack.
Preceding unsigned comment added by 194 237 142 21 14 36 20 september 2010 utc.
All racks used for n series storage system installation must conform to the specifications in this section.
The funny thing is.
The u space starts and stops in the middle of the 1 2 holes.
Rack nuts are not standard.
Rack hole spacing for rack unit mounts.
The whole spacing alternates at 1 2 5 8 5 8 and then repeats.
Racks are divided into regions 1 75 inches in height within which there are three complete hole pairs in a vertically symmetric pattern the holes being centred 0 25 inch 6 4 mm 0 875 inch 22 2 mm and 1 5 inch 38 1 mm from the top or bottom of the region.
This three hole group is defined as a rack unit ru or sometimes just call a u.
This specification standardizes several important features of 19 racks such as the rack unit ru or u vertical hole spacing horizontal hole spacing rack opening and front panel width.
To determine if your rack is a 19 rack measure the hole to hole spacing.
I don t know why the article says the next innovation in rack design has been the square hole rack.
The specification also sets tolerances on each of these dimensions.
Horizontal spacing of rack units depend on whether or not the holes are drilled and tapped in the rack versus the use of cage nuts.
Horizontal spacing of vertical rows is specified by eia 310 at 18 5 16 18.
The eia 310 specification has been the 19 racks standard for equipment for 50 years.
The term 19 inch comes from the width of the front panel of the boxes that are installed in the rack see the image below.
Both the ibm 7014 model t00 and model t42 and the ibm 2101 model n00 racks conform but some other racks including a few from ibm do not.
19 rack 18 5 16 18 312 465 1 mm.
The hole spacing for standard 19 inch racks on the mounting flange is spaced in groups of three holes.
