Bookmark the official ANSI store page for "ANSI/EIA-310-D-1992" (or the current revision). For immediate reference, download a free, reputable dimensional summary from a major rack vendor. Your infrastructure will thank you.

EIA-310-D specifies a unique, repeating vertical hole pattern for the mounting rails. This pattern repeats every 1.75 inches (1U) and consists of three distinct hole intervals. The 1U Hole Pattern

The original EIA-310-D document has gone through several hands over the years (moving through the ECA and now often referenced under or ANSI banners). While the full technical PDF is often behind a paywall at standards organizations like IHS Markit or ANSI , many manufacturers provide detailed summaries in their installation guides, such as the Schneider Electric FAQ or AWS Outposts Documentation .

Because the Electronic Industries Alliance (EIA) dissolved in 2011, official engineering PDFs and historical hardcopies of the standard are maintained and distributed by authorized standards bodies.

This is a newer revision, focusing on further strengthening the metric standards.

Offers deployment flexibility similar to square holes but does not support modern toolless rapid rails. 3. Threaded Holes (#10-32, #12-24, or M6)

Defines the "U" (Rack Unit), rack width, and hole spacing (mounting flanges).

The EIA310D standard is a specification that defines the mechanical and environmental requirements for electronic components, such as capacitors, resistors, and inductors. The standard covers various aspects, including: