An assembly comprising a connector assembly and a mating connector assembly, the connector assembly comprising: a housing having a mating face configured to mate with and unmate from the mating connector assembly; a power supply contact disposed within the housing and configured to mate with a mating power contact in the mating connector assembly; an interlock circuit contact disposed within the housing and configured to mate with a mating interlock contact in the mating connector assembly to control transfer of the electric power through the power supply contact; a lever subassembly pivotally coupled to the housing and comprising a handle and a gripping end that engages the mating connector, the lever subassembly configured to move the housing relative to the mating connector when the handle is rotated to sequentially unmate the interlock circuit contact from the mating interlock contact prior to unmating the power supply contact from the mating power contact, and a lever latch coupled with the housing, characterized in that the lever subassembly further comprises a slide bar coupled to the handle and slidably joined to the housing such that rotation of the handle moves the slide bar linearly relative to the housing; and the lever latch being arranged such that, by blocking rotation of the lever subassembly by blocking movement of the slide bar, the lever latch: (i) prevents unmating of the power supply contact from the mating power contact when the power supply contact is mated with the mating power contact and the interlock circuit contact is mated with the mating interlock circuit contact; then (ii) is depressable to be moved out of a path of the slide bar to permit unmating of the interlock circuit contact and the mating interlock circuit contact; then (iii) prevents unmating of the power supply contact from the mating power contact after the interlock circuit contact is unmated from the mating interlock contact; then (iv) is depressable to release the slide bar from engagement with the lever latch to permit unmating of the power supply contact and the mating power contact. a housing having a mating face configured to mate with and unmate from the mating connector assembly; a power supply contact disposed within the housing and configured to mate with a mating power contact in the mating connector assembly; an interlock circuit contact disposed within the housing and configured to mate with a mating interlock contact in the mating connector assembly to control transfer of the electric power through the power supply contact; a lever subassembly pivotally coupled to the housing and comprising a handle and a gripping end that engages the mating connector, the lever subassembly configured to move the housing relative to the mating connector when the handle is rotated to sequentially unmate the interlock circuit contact from the mating interlock contact prior to unmating the power supply contact from the mating power contact, and a lever latch coupled with the housing, (i) prevents unmating of the power supply contact from the mating power contact when the power supply contact is mated with the mating power contact and the interlock circuit contact is mated with the mating interlock circuit contact; then (ii) is depressable to be moved out of a path of the slide bar to permit unmating of the interlock circuit contact and the mating interlock circuit contact; then (iii) prevents unmating of the power supply contact from the mating power contact after the interlock circuit contact is unmated from the mating interlock contact; then (iv) is depressable to release the slide bar from engagement with the lever latch to permit unmating of the power supply contact and the mating power contact.