By "19" systems" we are referring to rack systems with a usable width of 84 horizontal pitch units (HP) of 2 inches or 5.04 mm and a usable height of a multiple of the rack unit (U) of 1 ¾ inches or 44.45 mm. This leads to certain specifications for the width and height of the suitable 19" partial front panels.

19" partial front panels are required to make printed circuit boards with the aid of fasteners into modules, which can in turn be inserted and fastened in 19" racks. Under certain circumstances a number of racks may be mounted in cabinets or other enclosures – the so-called "19" rack systems".

A horizontal pitch unit (HP) is a unit of measurement to describe the width of an equipment module rack. One HP corresponds to 1/5 inch, or 5.08 mm. Consequently a 19 inch wide front panel covers 95 horizontal pitch units.

A rack unit (U) is a unit of measurement to describe the height of an equipment module rack. One U corresponds to 1¾ inches, or 44.45 mm. The most common heights are 3 U and 6 U.

Partial front panels, which are intended for a certain combination of pitch and rack units, have to be a certain amount smaller than the theoretical respective dimensions for width and height, so that they can be easily mounted alongside other front panels.

If one module only takes up a part of the width of 84 pitch units (HP) available, then it is connected with a so-called "partial front panel", whose width is that number of HP units minus a certain amount (0.34 mm).

The height of the 19" partial front panel is a multiple of the rack unit (U) minus a certain amount (4.95 mm).

As the 19" partial front panel is ideally mounted to two rails with threaded holes in the 19" rack system, the placement of system holes on the 19" front panel is required.

If you select "19" partial front panels" from the list box "Dimensions in 19" units" in the properties dialog box for the front panel, both width and height can be set in pitch and rack units. As a result the necessary standard deductions allowing problem-free assembly are automatically taken into consideration.

In the event that a module takes up all 84 HP of the interior of the 19" rack, then the front panel will be attached to a 95 HP (= 19 inches or 463 mm) wide front panel with several screws on both the left and right edges of the rack.

A value of 465.1 mm has been established as a standard for the horizontal distance between the two rows of bolts. The height of the 19" front panel is generally a multiple of the rack unit (U) minus a certain amount (0.85 mm).

Example of a 19" front panel from one of the enclosure templates

If you select "19" front panel" as the system from the list box "Dimensions in 19" units" in the properties dialog box for the front panel, then the width is set to 482.6 mm whereas the height can be entered in rack units. As a result the necessary standard deduction allowing problem-free assembly is automatically taken into consideration.