How to Calculate the U Height Required for a Service Cabinet

Server cabinets have an internal height measured in U where 1U=44.45mm. This standardisation allows rack mounted device height requirements to be totalled. The vertical pillars in a server cabinet are normally marked from 1 and the bottom of a rack to the top U height which can be from 4U up to 47U or higher. To accommodate equipment not designed to be rack mounted, additional shelves (fixed, adjustable, and telescopic) can be added to a server cabinet. These attach as does any rack mounted devices with M5 cage nuts and bolts.