For questions about an [electrical-panel] that is fed from another [electrical-panel] instead of being fed directly by a utility service or separately derived service (such as a generator or inverter).

A subpanel is a type of where the incoming power supply comes from another on the premises, instead of directly from a utility service or a separately derived service such as a generator or an inverter. They are often found in larger homes and structures where a single electrical panel doesn't provide enough space, or detached outbuildings with multiple circuits of their own are present. They are also required in multi-tenant/multi-family buildings (such as apartments and condos) in order to provide each tenant or dwelling unit with control over the circuits within their own space.