BZ-3AT Snap Action Switch - Equivalent & Substitute Parts

Part Overview

The BZ-3AT is a snap action switch manufactured by Honeywell Sensing and Productivity Solutions, configured as a Single Pole Double Throw (SPDT) device with chassis mount installation. This switch is rated for 15A AC at 125V and features a round pin plunger actuator with screw terminal connections. The product is classified as obsolete, making equivalent substitute parts necessary for ongoing applications and new designs requiring similar electrical and mechanical characteristics.

Substiute Parts

BZ-3AT

Honeywell Sensing and Productivity SolutionsIn Stock: 1090BZ-3AT Datasheet

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A-20G-B

Omron Automation and SafetyIn Stock: 831A-20G-B Datasheet

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Z-15GM22-B

Omron Automation and SafetyIn Stock: 964Z-15GM22-B Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the BZ-3AT is determined by strict alignment of the following electrical and mechanical parameters:

Primary Substitution Criteria:

• Circuit configuration: SPDT topology required
• Switch function: On-Momentary operation
• AC voltage rating: Minimum 125V
• AC current rating: Minimum 15A
• Mounting type: Chassis mount configuration
• Termination style: Screw terminal connections
• Actuator type: Compatible mechanical interface

Substitute Parts Identified:

A-20G-B (Omron Automation and Safety): Meets primary electrical criteria with 20A AC rating at 125V, exceeding the 15A requirement. SPDT configuration and chassis mount installation are compatible. Round pin plunger actuator and screw terminal termination match the BZ-3AT interface. Product status is active with current availability.

Z-15GM22-B (Omron Automation and Safety): Matches the 15A AC rating at 125V exactly. SPDT configuration and chassis mount installation are identical. Screw terminal termination is compatible. Actuator type differs (lever roller versus round pin plunger), representing a mechanical interface variation. Product status is active with current availability.

Parameter Comparison

Engineering Selection Recommendations

A-20G-B Selection Criteria:

The A-20G-B provides direct substitution for applications where the 15A AC requirement is the primary constraint. The 20A AC rating provides current margin above the BZ-3AT specification. Both devices share identical round pin plunger actuator geometry and screw terminal interface, enabling direct mechanical and electrical replacement in existing designs. The A-20G-B is manufactured by Omron Automation and Safety with active product status and ROHS3 compliance, ensuring long-term availability and regulatory alignment. DC current capability increases from 1A to 6A, though DC voltage rating reduces from 125V to 30V. Operating temperature range narrows from -55°C to 85°C to -25°C to 80°C. Mechanical life decreases from 20,000,000 cycles to 1,000,000 cycles.

Z-15GM22-B Selection Criteria:

The Z-15GM22-B provides exact AC current and voltage matching at 15A and 125V. This device is manufactured by Omron Automation and Safety with active product status and ROHS3 compliance. The primary distinction is the actuator type: lever roller configuration versus round pin plunger. This mechanical difference requires evaluation against the application's physical space constraints and actuation method. DC current capability increases to 6A with DC voltage rating of 30V. Operating temperature range is -25°C to 80°C. Mechanical life is 10,000,000 cycles, representing a 50% reduction from the BZ-3AT but exceeding the A-20G-B specification.

Compliance and Availability:

Both substitute parts carry ROHS3 compliance and MSL 1 ratings, meeting modern regulatory requirements. Both are classified as active products with current inventory availability, eliminating obsolescence risk associated with the BZ-3AT.

Frequently Asked Questions (FAQ)

Q: Can the A-20G-B directly replace the BZ-3AT in all applications?

A: The A-20G-B meets all primary electrical substitution criteria for 125V AC applications requiring 15A switching. The identical round pin plunger actuator and screw terminal configuration enable direct mechanical replacement. However, the reduced operating temperature range (-25°C to 80°C versus -55°C to 85°C) and lower mechanical life (1,000,000 versus 20,000,000 cycles) must be evaluated against specific application requirements.

Q: What is the primary difference between the A-20G-B and Z-15GM22-B?

A: The A-20G-B features a round pin plunger actuator identical to the BZ-3AT, while the Z-15GM22-B uses a lever roller actuator. The A-20G-B provides 20A AC current capacity, while the Z-15GM22-B matches the BZ-3AT at 15A AC. The Z-15GM22-B offers superior mechanical life (10,000,000 cycles) compared to the A-20G-B (1,000,000 cycles).

Q: Are there DC application considerations for these substitutes?

A: The BZ-3AT is rated for 1A DC at 125V. Both substitute parts increase DC current to 6A but reduce DC voltage rating to 30V. Applications requiring DC switching above 30V are not compatible with either substitute. DC applications below 30V benefit from increased current capacity.

Q: How do operating temperature ranges affect substitution?

A: The BZ-3AT operates from -55°C to 85°C. Both substitutes narrow this range to -25°C to 80°C. Applications requiring operation below -25°C or above 80°C are not compatible with either substitute part.

Q: What is the mechanical life significance in substitution?

A: The BZ-3AT specifies 20,000,000 mechanical cycles. The A-20G-B provides 1,000,000 cycles, while the Z-15GM22-B provides 10,000,000 cycles. Applications with high cycle count requirements must evaluate whether the reduced mechanical life of the A-20G-B is acceptable, or if the Z-15GM22-B is the preferred choice.

Q: Are both substitutes RoHS compliant?

A: Yes. Both the A-20G-B and Z-15GM22-B carry ROHS3 compliance, meeting current regulatory requirements. The BZ-3AT carries RoHS compliance. All three parts are MSL 1 rated with unlimited moisture sensitivity.

Q: What packaging considerations apply to these parts?

A: The BZ-3AT is supplied in standard packaging. The A-20G-B and Z-15GM22-B are supplied in bulk packaging. Procurement processes should account for bulk packaging requirements and minimum order quantities.