This denotes the physical footprint. In most industrial contexts, this means the component occupies 4 vertical units of space and has a depth or width of 18 inches/units . Common Applications
High-capacity modular assemblies that distribute power across a specific number of outlets or circuits.
4U components generate significant heat; maintain at least 1U of "air gap" above the unit if it lacks active internal fans.
Do you have a name or a photo of the device to narrow down the exact wiring or software setup?
