The Allen-Bradley Bulletin 140U 140U-N5L3-E12 circuit breaker is an assembled 3-pole circuit breaker with an electronic trip unit. The protection type available on the electronic trip unit is the LS type (long time and short time). The LS protection feature enables the adjustment of the long time between 1.05 and 1.3x the thermal rating to be delayed, and it also enables the adjustment of the short time between the thermal and short circuit protection. The breaking capacity / interrupting capacity range for the 140U-N5L3-E12 circuit breaker is 50 to 59 kiloamps. The thermal trip for the 140U-N5L3-E12 circuit breaker can be set between 600 Amps and 1200 Amps. The magnetic trip rating can be set between 1200 Amps and 10600 Amps. The continuous current rating for the 140U-N5L3-E12 circuit breaker is 1200 Amps. The 140U series N-frame breakers are approved by the KEMA, CCC, CE, and IEC standards.

The power dissipated as heat during operation by the 140U-N5L3-E12 circuit breaker is 210 Watts. The mechanical specifications include a circuit breaker weight of 46.9 pounds and circuit breaker dimensions of 15.98 x 8.27 x 4.089 inches. The recommended ambient temperature range for the circuit breaker operation is from 16 to 140 degrees Fahrenheit. The rated insulation voltage for the main poles is 750 Volts AC. The rated impulse withstand voltage for the main conductors is 8 kilovolts. The rated operational voltage is 690 Volts AC according to the IEC standards at 50 Hertz and it is 600 Volts AC according to the UL / NEMA standards at 60 Hertz. The service breaking capacity ratings at 50 Hertz for the 140U-N5L3-E12 circuit breaker are as follows: 85 kiloamps at 240 Volts AC, 50 kiloamps at 380 Volts AC, and 10 kiloamps at 690 Volts AC.