NOARK Miniature Circuit Breaker UL 1077

Noark UL1077 Miniature Circuit Breaker
Noark UL1077 Miniature Circuit Breaker

Miniature circuit breakers have different protection curves to accommodate different applications

C Curve

In Type C curve applications, the magnetic trip is set between 5-10 times the full load current. This is the most common protection used for cables, lighting, resistive loads, general purpose applications and when properly sized, for motors.
typical C curve applications for a Noark UL1077 Miniature Circuit Breaker

D Curve

Type D curve applications have a higher setting of 7-15 times the full load current due to the inrush current of motor loads and the magnetizing current on the primary of a transformer or solenoid. Application for this curve include motor loads, transformer primary and solenoids due to the inrush or magnetizing currents.
typical D curve applications for a Noark UL1077 Miniature Circuit Breaker

B Curve​

Type B curves provide a magnetic trip setting of 3-5 times the full load current. Applications: electronic circuits.
typical B curve applications for a Noark UL1077 Miniature Circuit Breaker
Noark UL1077 Miniature Circuit Breaker Product Selection
  • UL 1077 No. E355391 / IEC 60947-2
  • Supplementary Protectors are UL Recognized for use in the United States in accordance with NFPA® 70 (NEC).
  • These devices comply with UL 1077 No. E355391 and UL recognized for Canada CSA standards 22.2 No. 5 meeting the requirements for supplementary protectors.
  • These devices are for international and domestic use, and also comply with IEC 60947-2 and are CE marked.

UL 1077 devices are only acceptable for providing supplementary protection where there is branch circuit protection ahead of it.

UL 489 products have larger dimensions to provide the necessary phase to phase voltage air gap.

The B1E UL 1077 miniature circuit breaker has a complete range of amperages from 1A to 125A. Standard ratings of 5 kA at 480Y/277 Vac and 10 kA at 240 Vac. These are suitable for supplementary protection.

• Breakers mount on standard 35 mm DIN rail
• Thermal-magnetic over current protection – three levels of protection, categorized by B, C and D curves

• Fulfills UL 1077, IEC 60947-2 standard
• Field-installable shunt trip and auxiliary switch up to 63A
• Module width of only 0.71 in (18 mm) per pole
• Contact position indicator (red/green)
• 5-Year limited warranty

UL 1077 Supplementary Protectors & Overcurrent Devices

UL 1077 Supplementary Protector is a manually resettable device designed to open the circuit automatically on a predetermined value of time versus current or voltage within an appliance or other electrical equipment. A supplementary protective device is intended to provide limited overcurrent protection for specific applications and utilization equipment such as cabinet lighting and appliances.

UL 1077 Applications

• Cabinet Lighting
• Appliances
• Control Power Transformers
• Relays
• Control Circuits


• DIN rail mountable
• Field mounted accessories
• Various levels of protection (curves

Typical Applications

• Supplementary protection control circuits
• Cabinet lighting
• Appliances


Noark UL1077 Miniature Circuit Breaker Shunt Trip Under Voltage Trip
Shunt Trip
Under-Voltage Trip
Noark UL1077 Miniature Circuit Breaker Alarm Switch Auxillary Contact
Alarm Switch
Auxiliary Contact