A fuse lock-out assembly for a battery pack, comprising: a first housing having an interior region configured to hold a manual service disconnect lower housing and a manual service disconnect upper housing therein; a fuse holding housing coupled to the first housing, the fuse holding housing having a first fuse compartment configured to hold a first fuse therein; a slidable door being slidably coupled to the first housing, the slidable door configured to slide from a first operational position to a second operational position; the slidable door being configured to cover an open end of the first fuse compartment at the first operational position to prevent the first fuse from being removed from the first fuse compartment; wherein the slidable door is further configured to extend over a portion of the manual service disconnect lower housing at the second operational position only if the manual service disconnect upper housing is previously decoupled from the manual service disconnect lower housing, the slidable door is further configured to not cover the open end of the first fuse compartment at the second operational position, the slidable door at the first operational position does not interfere with the manual service disconnect upper housing being decoupled from the manual service disconnect lower housing in the interior region, when the slidable door is slidable from the first operational position at least partially into the interior region, the slidable door is configured to abut against the manual service disconnect upper housing if the manual service disconnect upper housing is coupled to the manual service disconnect lower housing in the interior region, such that the slidable door cannot extend to the second operational position, and the slidable door at least partially covers the open end of the first fuse compartment when the slidable door is disposed between the first and second operational positions such that the first fuse is not accessible, wherein the slidable door has a gasket configured to contact a plate portion of the housing around the open end of the fuse compartment, when the slidable door is at the first operational position to provide a fluid-tight seal around the open end of the fuse compartment. a first housing having an interior region configured to hold a manual service disconnect lower housing and a manual service disconnect upper housing therein; a fuse holding housing coupled to the first housing, the fuse holding housing having a first fuse compartment configured to hold a first fuse therein; a slidable door being slidably coupled to the first housing, the slidable door configured to slide from a first operational position to a second operational position; the slidable door being configured to cover an open end of the first fuse compartment at the first operational position to prevent the first fuse from being removed from the first fuse compartment; wherein the slidable door is further configured to extend over a portion of the manual service disconnect lower housing at the second operational position only if the manual service disconnect upper housing is previously decoupled from the manual service disconnect lower housing, the slidable door is further configured to not cover the open end of the first fuse compartment at the second operational position, the slidable door at the first operational position does not interfere with the manual service disconnect upper housing being decoupled from the manual service disconnect lower housing in the interior region, when the slidable door is slidable from the first operational position at least partially into the interior region, the slidable door is configured to abut against the manual service disconnect upper housing if the manual service disconnect upper housing is coupled to the manual service disconnect lower housing in the interior region, such that the slidable door cannot extend to the second operational position, and the slidable door at least partially covers the open end of the first fuse compartment when the slidable door is disposed between the first and second operational positions such that the first fuse is not accessible, wherein the slidable door has a gasket configured to contact a plate portion of the housing around the open end of the fuse compartment, when the slidable door is at the first operational position to provide a fluid-tight seal around the open end of the fuse compartment.