Square D QOU250 Qo Miniature Circuit Breaker Brand: Square D. Part Number: QOU250. Square D QO Miniature Circuit Breaker, Type QOU Standard Unit Mount, 120/240 V AC, 50 A, 50/60 Hz, 10 kA Interrupt, Thermal Magnetic Trip, 2 Pole, 1 ph, Toggle Actuator, Box Lug, 14 to 2 AWG Wire, DIN Rail/Flush Mount, 104 deg F, 2.95 in L x 1.5 in W x 4.05 in H, Black. Additional Description: SQD -QOU250 MINIATURE CIRCUIT BREAKER 120/240V 50A 50A 120/240V. Catalog Description: Mini circuit breaker, QOU, 50A, 2 pole, 120/240VAC, 10kA..