What does “recommended equipment depth” mean, and why is it smaller than the cabinet’s usable depth?

It’s the depth we’d normally suggest designing around rather than attempting to occupy every last millimetre inside the enclosure.

The difference gives you working room for rear connectors, cable bends, rail adjustment and front clearance. It also leaves some tolerance for those irritating parts of real equipment that specification drawings sometimes make look almost apologetically insignificant.

Our recommended equipment depths are approximately 200mm in a 300mm cabinet, 350mm in a 450mm cabinet, 450mm in a 550mm cabinet and 500mm in a 600mm cabinet.

A 250mm internal space doesn’t mean a 249mm-deep device is a good idea if its power plug then needs another 35mm in which to exist.

Think of the recommendation as comfortable working territory rather than the physical edge of the map.