What are the dimensions of 19-inch IEC 60297 standard subrack?

1. Width and Mounting (Critical Compatibility Dimensions)

Front Panel Mounting Width: 482.6 mm. This is the outer-edge width of the subrack’s mounting flanges (“ears”), ensuring compatibility with any standard 19-inch rack.

Mounting Hole Center-to-Center Distance: 465.0 mm ± 0.2 mm. This critical dimension, the distance between the mounting hole centerlines on both sides, must precisely match the corresponding holes on the rack’s vertical rails. It is essential for the smooth insertion and secure mounting of the subrack.

2. Height (Rack Units - ‘U’)

Height is measured in “U” or “Rack Units.” 1U = 44.45 mm.

A subrack nominally rated as *n*U will have a front panel height slightly less than *n* * 44.45 mm. This standard clearance allows for ventilation and installation of adjacent equipment (a typical compliant panel height is 43.6 mm per U).

Common Heights: 1U, 2U, 3U, 4U, 5U, 6U. Taller subracks accommodate more complex backplanes and multi-layer boards.

3. Depth

While no single depth is standard, the IEC defines a modular depth series.

Internal Module Mounting Depth: The usable depth within the subrack for installing PCBs/cards. Common values: 100 mm, 160 mm, 220 mm, 300 mm, etc.

Total Subrack Depth: Exceeds the internal mounting depth by approximately 30-50 mm to accommodate rear connectors (e.g., backplanes), cable management, and mounting hardware.

Selection Tip: Ensure the total subrack depth is less than your rack’s available depth, typically reserving at least 100 mm for cabling and airflow.

4. Horizontal Pitch (HP)

The Horizontal Pitch (HP) is the internal unit for measuring the width of plug-in units (cards).
1 HP = 5.08 mm (0.2 inches).

A standard 19-inch subrack typically provides an internal usable width of 84 HP (84 * 5.08 mm ≈ 426.7 mm).

Card widths are specified in multiples of HP (e.g., 3HP, 6HP, 12HP), enabling flexible configuration of modules within the same subrack.

Part 3: Typical Applications

Telecommunications & Networking: Traditional telecom switches, routers, and Optical Line Termination (OLT) platforms heavily utilize subrack architectures, where individual service cards act as plug-in units.

Industrial Computing & Automation: Industrial PC (IPC) chassis often employ a subrack form factor, allowing modular configuration with various CPU, I/O, and communication cards for rugged environments.

Modular Servers & Blade Centers: While blade servers have distinct standards, their modular design philosophy is analogous to subracks. Some high-density computing platforms still adopt the subrack form factor.

Test & Measurement Systems: Instrumentation chassis standards like PXI and VXI are evolutions of the subrack concept, used to build automated test systems.