Self-powered describes a USB hub or device that has its own dedicated power supply, usually a plug in adapter, rather than drawing all its electricity from the connected USB port. This is the opposite arrangement to a bus-powered device.
Because a self-powered hub brings its own power, it can supply full rated current to each of its downstream ports, which matters for demanding accessories such as external hard drives, multiple displays or devices that charge while in use. A bus-powered hub, by contrast, has to share the host port's limited current across everything connected to it.
When building a desk setup with several accessories, choosing a self-powered hub or dock generally leads to more reliable behaviour than relying on a bus-powered one, especially once storage devices or charging accessories are involved. See our guide to hubs and docks and our desk setup ideas for more.
