The Allen-Bradley 140U-K0D3-D40 UL listed Molded Case Circuit Breaker belongs to the bulletin 140U, K-Frame circuit breaker series with a high interrupting rating. This circuit breaker is intended to provide short-circuit protection and thermal overload protection to a high-performance industrial control panel. The 140U-K0D3-D40 Circuit Breaker features a compact package design that saves panel space and reduces operation costs, and it is designed to be compatible with reverse feed applications at 240 Volts AC and 480 Volts AC. The 140U-K0D3-D40 Circuit Breaker is also intended for use with feeder circuit applications (small cabinets, distribution panels, and branch circuits), and it can also be used with high-intensity discharge applications.

The 140U-K0D3-D40 Circuit Breaker has a 3-phase voltage rating of 480 Volts AC (at 50/60 Hertz) and a trip current rating of 400 Amps. It has a breaking capacity of 200 Kilo-Amps at 240 Volts AC and 100 Kilo-Amps at 480 Volts AC. The 140U-K0D3-D40 Circuit Breaker has a rated impulse withstand of 6000 Volts and a rated insulation voltage of 750 Volts. This circuit breaker is designed to have a mechanical lifespan of about 100,000 operations, and an electrical lifespan of up to 10,000 operations. The 140U-K0D3-D40 Circuit Breaker comes with a fixed thermal and adjustable magnetic trip unit that offers thermal overload and instantaneous trip action. The 140U-K0D3-D40 Circuit Breaker's thermal trip unit consists of a bimetal heating element that deflects and release a lever mechanism as the current load reaches the set value, thus causing a trip. It uses an electromagnetic device with adjustable trip settings (2000 to 4000 Amps) for actuating the instantaneous trip of the circuit breaker. The circuit breaker has a bolt-on type of terminal, and it comes with an open type of enclosure.