SharkRack 37U User Manual

Page of 46
SharkRack Enclosure Installation Guide 
ID-00210-000 
REV D, ECO2773 
Page 37 of 46 
 
Appendix A: Glossary 
 
EIA: 
For more than 72 years the Electronic Industries Alliance has been the national trade 
organization representing U.S. electronics manufacturers. Committed to the competitiveness of 
the American producer, EIA represents the entire spectrum of companies involved in the design 
and manufacture of electronic components, parts, systems and equipment for communications, 
industrial, government and consumer uses. 
 
U (or RU): 
A Rack Unit, or sometimes referred to as “U”, is the measure of space in a rack cabinet 
enclosure equal to 1.75 inches as defined by the EIA-310 standard. Each Rack Unit in an EIA 
rack cabinet enclosure will have three holes. The first hole is spaced at .25 inches from the 
bottom of the U to the center, followed by 2 holes spaced at .625 center to center and then .25 
inches to the top of the RU. 
 
Figure 39 
“U” Spacing 
 
 
Zero U:  
Zero U is any rack unit that is not a part of the main stacked rack unit in a cabinet.