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UL1077 Miniature Circuit Breakers

Uncompromising safety and comfort

UL1077 miniature circuit breakers (MCBs) ensure electrical safety in multiple applications. UL 1077 MCBs feature two different tripping mechanisms, the delayed thermal tripping mechanism for overload protection, and the magnetic tripping mechanism for short circuit protection.


  • Characteristics: B, C, D, K, Z
  • Configurations: 1P, 1P+N, 2P, 3P, 3P+N, 4P
  • Breaking capacities up to 25 kA
  • Rated currents up to 63A
  • Real contact position indication, directly connected to the moving contact


  • Extra-wide and complete range of MCBs to cover most applications and markets
  • Compliance with worldwide product standards (IEC, UL, CSA)
  • Space and time-saving thanks to the unique bottom-fixing auxiliary contact
  • Established and certified quality

Product Range


  • Trip curves B, C, D, K, and Z
  • 480Y/277 V AC and 60/125V DC (1-/2-,3-,4- pole)
  • 0.2 to 63A


  • Trip curves B, C, D, K, Z
  • Interrupt rating 10/5 kA (<32 A/35-63 A)
  • 277/Y480 VAC max., 60/125 VDC


  • Trip curve K
  • 277/Y480 VAC
  • Interrupt rating 10 kA
  • 0.5 to 63 A
  • Ring tongue terminals


  • Trip curves C, K, Z
  • 250/500 VDC
  • 0.5 to 63 A
  • Interrupt rating 10 kA


  • Trip curves B, C, D, K
  • 347/Y600 VAC max.
  • 0.5 to 63 A
  • Interrupt rating 30 kA max.


  • Trip curves B, C, D, K
  • 277/Y480 VAC, 500 VDC max.
  • 10 to 100 A
  • Interrupt rating 20 kA max.