EATON AZ-3-B40 3-Pole Miniature Circuit Breaker, 40A, B-Curve, 25kA

The EATON AZ-3-B40 is a robust 3-pole miniature circuit breaker engineered to provide high-level protection for electrical distribution systems. With a rated current of 40A and a B-type tripping characteristic, this device is specifically designed to handle the demands of commercial and industrial environments. Its high breaking capacity of 25kA ensures that it can safely interrupt fault currents, protecting sensitive equipment and infrastructure from the risks associated with overloads and short circuits.

Advantages

This circuit breaker offers exceptional reliability and durability, making it a dependable choice for critical power distribution tasks. The 3-pole configuration allows for the simultaneous disconnection of three phases, ensuring comprehensive safety across the entire circuit. Its B-curve characteristic provides a balanced response to overcurrent, preventing nuisance tripping while maintaining rapid protection during genuine electrical faults. The high breaking capacity of 25kA distinguishes this unit as a premium solution for installations where high fault currents are a potential concern.

Suitable for

• Industrial power distribution panels
• Commercial building electrical systems
• Protection of lighting and heating circuits
• General electrical infrastructure requiring high-capacity fault protection

When it may not be suitable

This device is not intended for residential applications where lower breaking capacities are standard and more cost-effective solutions are available. It is also not suitable for circuits requiring C or D curve tripping characteristics, which are designed for high-inrush current loads like large motors or transformers.

Key specifications

• Number of poles: 3
• Rated current: 40A
• Tripping characteristic: B-curve
• Breaking capacity: 25kA
• Mounting type: DIN rail

How to use

The EATON AZ-3-B40 should be installed by a qualified electrician in accordance with local electrical regulations. It is designed for mounting onto a standard DIN rail within a distribution board or enclosure. Ensure that the supply cables are securely connected to the terminals, observing the correct torque settings to prevent overheating. Once installed, the toggle switch can be used to manually open or close the circuit, while the internal mechanism will automatically trip the breaker in the event of an electrical fault.

What to consider before purchase

• Verify that the 40A rating matches your circuit requirements
• Ensure the B-curve characteristic is appropriate for your specific load type
• Confirm that the 25kA breaking capacity is sufficient for the prospective short-circuit current at the installation point
• Check available space in your distribution board for a 3-pole device

Usage recommendations

Regular inspection of the circuit breaker and its connections is recommended to ensure long-term operational safety. Do not attempt to bypass or modify the device, as this will compromise its protective functions and void safety certifications.