5.4 Enclosures

The case a module screws into. An enclosure is made of rows; each row has a pair of rails with an insert in each, and usually a bus board behind the panels.

Rows

An enclosure shall publish, for each row, its width in HP and the depth it keeps clear behind the panel's back face (ENC-001).

A row is 1U or 3U, matching the front panels it holds; a 6U case is two 3U rows. A row's usable width is a whole number of HP. 84 HP fits a 19-inch rack; wider rows, such as 104 HP, are the maker's choice.

Frame

The frame is a 19-inch rack frame, which meets RACK-003 (5.1), or a desktop or portable frame with the same rows and hole span (5.3).

The front rails take the mounting screws of 5.3, whose length the enclosure publishes (RAIL-011). Other rails carry the bus board or stiffen the frame. The enclosure publishes which of its metal parts are bonded to one another and where its metalwork takes a bond to the row's 0 V (GND-005, 6.3): anodized rails and inserts lying in them are not bonded by their fit. Mains inlet, fusing, and the construction of a supply are outside EIS.

Depth

EIS recommends that a row keep at least 50 mm clear behind the panel's back face, the module depth 5.2.2 recommends. A rail of the recommended section (5.3) is 25 mm to 28.5 mm deep, front face to back face. In the case catalog behind the eis-reference survey, 20 of 25 current cases give 50 mm somewhere in the row and 17 give it over the whole row; the shallow part is usually over the supply or the bus board.

EIS · A 3U row cut from front to back case rail panel module board face bus board ribbon supply module depth clear depth Both depths are measured from the panel's back face. The module publishes its width in HP and its depth (PANEL-003). The enclosure publishes each row's width in HP and its clear depth (ENC-001): the least depth, across the row, to the nearest thing behind the panels. Here that is the supply; often it is the bus board. A module fits a row when its depth is no more than the row's clear depth. EIS recommends rows at least 50 mm clear and modules at most 50 mm deep.

Built-in supply and bus board

An enclosure with a built-in supply is also a power supply, and one with a built-in bus board is also a bus board. Each built-in part claims its own role (4.1), and the enclosure's documentation carries what each publishes:

EIS recommends that an enclosure publish, for each row, the dissipation it carries for a 10 °C rise above room temperature; Annex H gives the method.

The informative row budget is a planning table for one row: header count, bus and supply currents, and video sync distribution.