Essential loads

Essential loads are the selected loads, circuits or sockets that a backup or island-mode battery system is designed to keep supplied when the grid is unavailable. In product and commissioning documents the same idea may appear as maintained loads, maintained circuits, dedicated EPS circuits or an essential supply. The term does not mean the whole property is backed up: the selected loads still need to fit within the inverter output, available battery energy, circuit arrangement, earthing, protection and commissioning checks. The important distinction is between loads deliberately connected to the backup supply and non-essential loads that remain on the normal supply and go off during the outage.