I want to install some hardware in a rack. Can someone tell me if there is an industry standard for where a U number is started at the bottom of a rack? Do they call the bottom spsce 0 or 1? How much is a U?
There are several standards used for the width of a rack I know of 19", 23", and 24". The 19" is regarded as the standard. The "Rack Unit" or "U" is an EIA standard measuring height. One "Rack Unit" is equal to 1.75". When you buy a rack it is sold as for example a 44U rack enclosure and would have an internal height of 77" (1.75 x 44).
"Free will is an illusion. People always choose the perceived path of greatest pleasure"
The U count in racks I have worked on start from 1 at the bottom. They are often clearly marked but as a guide, there are 3 holes per U. With new kit you often get a template to help line things up. Don' forget health and safety, populate from the bottom and either use a lift tool or have plenty of muscle to assist.
On the safety note, please make sure the Rack, if made from conductive material is electrically safe. I have tested many racks built up and operational, but safe no.
A couple of weeks ago I have tested one rack that you could measure 110volts on the frame work. Good job there wasn't an earth on the other cab I was leaning against.
"Free will is an illusion. People always choose the perceived path of greatest pleasure"
