The Allen-Bradley Bulletin 140U series 140U-H3C3-D12 circuit breaker is a 3-pole circuit breaker that is designed to provide overload and short-circuit protection. This 125 Amps rated circuit breaker can be used for both branch circuit protection and main circuit protection in individual enclosures, panelboards, and switchboards. The wide interrupting range allows a single circuit breaker to address multiple applications. Accessories can be installed in the field which saves time and increases flexibility. The compact circuit breaker design leads to further space conservation. The 140U-H3C3-D12 circuit breaker is a Frame H circuit breaker with a thermal-magnetic trip unit. It weighs approximately 1.36 kilograms and it measures 5.5 x 3 x 3 inches. The ambient operating temperature range for the 140U-H3C3-D12 circuit breaker is from -8.9 to 60 degrees Celsius.

The circuit breaker has a breaking capacity range of 30 to 39 kiloamps. At 50 Hertz frequency, the 140U-H3C3-D12 circuit breaker offers 85 kiloamps of ultimate breaking capacity and 43 kiloamps of service breaking capacity at 220 or 240

Volts AC, 40 kiloamps of ultimate breaking capacity and 30 kiloamps of service breaking capacity at 380 or 415 Volts AC, 25 kiloamps of ultimate breaking capacity and 18 kiloamps of service breaking capacity at 525 Volts AC, and 4 kiloamps of ultimate breaking capacity and 3 kiloamps of service breaking capacity at 690 Volts AC. The insulation voltage rating according to the IEC 60947-2 standards is 690 Volts AC for the auxiliary circuit and 750 Volts AC for the main poles. The impulse withstand ratings are 4 kilovolts for the auxiliary circuits and 6 kilovolts for the main breaker conductors. Up to 25 Watts of energy is dissipated as heat during operation under normal load conditions.