Eaton NZMB1-A40 3-Pole Circuit Breaker, 40 A, 690 V AC, Thermal-Magnetic 259075

This Eaton NZM1 series circuit breaker stands out with its robust 3-pole design and thermal-magnetic trip unit, delivering reliable protection for industrial power distribution systems up to 690 V AC. Unlike many breakers in its class, it offers a fixed short-circuit release set at 10 times the rated current, ensuring fast response to high fault currents.

Highlights

• 3-pole configuration for three-phase systems
• Rated current of 40 A with fixed thermal and magnetic releases
• High short-circuit breaking capacity of 25 kA at 400/415 V AC
• Compact NZM1 frame size for space-saving installation
• Front screw terminals for secure and easy wiring

In daily use

Designed for fixed installation in control panels and switchgear, the NZMB1-A40 provides dependable overload and short-circuit protection for motors, cables, and other loads. Its thermal-magnetic trip unit reacts predictably to both gradual overloads and sudden faults, minimizing downtime and equipment damage. The IP40 front protection and IP20 terminal protection make it suitable for standard industrial environments.

Full specifications

• Number of poles: 3
• Rated current (In): 40 A
• Rated operational voltage (Ue): 690 V AC
• Rated insulation voltage (Ui): 690 V
• Rated impulse withstand voltage (Uimp): 6 kV
• Short-circuit breaking capacity (Icu) at 400/415 V: 25 kA
• Short-circuit breaking capacity (Icu) at 690 V: 5 kA
• Short-circuit service breaking capacity (Ics): 25 kA (100% of Icu at 400/415 V)
• Trip unit type: Thermal-magnetic
• Overload release setting (Ir): Fixed at 40 A
• Short-circuit release setting (Ii): Fixed at 400 A (10 x In)
• Mounting type: Fixed installation
• Connection type: Front connection (screw terminals)
• Standard: IEC/EN 60947-2
• Degree of protection (front): IP40
• Degree of protection (terminals): IP20
• Operating temperature range: -25 to +70 °C
• Series: NZM1

Final note

Trusted by panel builders and maintenance engineers, the Eaton NZMB1-A40 combines proven performance with a compact footprint, making it a reliable choice for demanding electrical distribution applications.