The 140U-Q3X3 circuit breaker is a circuit breaker with a Q-frame enclosure. The maximum current rating for the Q-frame circuit breaker is 600 Amps. Different trip units can be installed on the 140U-Q3X3 depending on customer requirements. Both thermal-magnetic and electronic trip units can be installed on the 140U-Q3X3 circuit breaker. The compatible thermal-magnetic trip units include the 140U-QTD3-D30 unit which has 300 Amps of rated current, 300 Amps thermal trip current, and 1500 to 3000 Amps of magnetic trip current, the 140U-QTD3-D35 unit which has 350 Amps of rated current, 350 Amps of thermal trip current, and 1750 to 3500 Amps of magnetic trip current, the 140U-QTD3-D40 unit which has 400 Amps of rated current, 400 Amps of thermal trip current, and 2000 to 4000 Amps of magnetic trip current, and the 140U-QTD3-D45 unit which has 450 Amps of rated current, 450 Amps of thermal trip current, and 2250 to 4500 Amps of magnetic trip current.

The 140U-QTD3-D50 unit which has 500 Amps of rated current, 500 Amps of thermal trip, and 2500 to 5000 Amps of magnetic trip, and the 140U-QTD3-D60 unit which has 600 Amps rated current, 600 Amps thermal trip, and 3000 to 6000 Amps magnetic trip can also be used. The compatible electronic trip modules include the 140U-QTL3-D60 unit with LS protection which has 600 Amps of rated current, 400 to 600 Amps of thermal trip, and 800 to 4800 Amps of magnetic trip, the 140U-QTH3-D60 unit with LSI protection which has 600 Amps of rated current, 400 to 600 Amps of thermal trip, and 800 to 4800 Amps of magnetic trip, and the 140U-QTG3-D60 unit with LSG protection which has 600 Amps of rated current, 400 to 600 Amps of thermal trip, and 800 to 4800 Amps of magnetic trip. The 140U-Q3X3 circuit breaker has three poles and dimensions of 12.5 x 8.25 x 4.37 inches.