FIELD: electrical engineering. SUBSTANCE: invention refers to devices preventing drop of rated power of cut-off of automatic switch after installation of auxiliary unit such as differential protection device. Proposed device includes means of adjustment of thermal cut-off of automatic switch 11 when auxiliary unit 10 is installed. In automatic variant these means incorporate adjustment bar 17 composed of part 13 interacting with actuating mechanism 12 firmly joined to auxiliary unit. Adjustment bar has bulges 17a, 17b, 17 c, 17d which act on bimetal strips 16a, 16b, 16c, 16d of means of thermal cut-off on each pole of automatic switch. EFFECT: taking into account of balance of heat exchange of automatic switch that occurs with installation of auxiliary unit. 15 cl, 12 dwg
