DC disconnector
Also known as: DC isolator, DC switch-disconnector
A manually operated switching device that provides a visible, lockable isolation point in the DC circuit, used to create a safe de-energised condition for maintenance. It is most commonly located at the PCS DC input — often integrated into the PCS as a load-break switch-disconnector — isolating the battery bus from the power electronics. A plain disconnector is not intended to break fault current; that is the contactor's and fuse's role.
In energy storage
On the battery side, operational connect/disconnect is handled by BMS-controlled DC contactors rather than a manual switch; some vendors add a service disconnect so individual racks can be isolated, but this varies by product. The dedicated DC disconnector a technician operates is usually the one at the PCS DC input, giving the lockable isolation point required for lock-out/tag-out (LOTO) before working on the conversion equipment.