BZ-3R-A2 Snap Action Switch SPDT Equivalent & Substitute Parts

Part Overview

The Honeywell BZ-3R-A2 is a snap action switch with Single Pole Double Throw (SPDT) circuit configuration, rated for 15A AC at 125V. This component features a round pin plunger actuator, chassis mount design, and screw terminal termination. The BZ-3R-A2 is classified as obsolete, making equivalent substitute parts necessary for ongoing system maintenance, repair, and new design implementations where this specific model is no longer available from the manufacturer.

Substiute Parts

BZ-3R-A2

Honeywell Sensing and Productivity SolutionsIn Stock: 1177BZ-3R-A2 Datasheet

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A-20GD-B7-K

Omron Automation and SafetyIn Stock: 1168A-20GD-B7-K Datasheet

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Z-15G-B

Omron Automation and SafetyIn Stock: 1404Z-15G-B Datasheet

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Z-15GD-B7-K

Omron Automation and SafetyIn Stock: 951Z-15GD-B7-K Datasheet

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Z-15GD55-B7-K

Omron Automation and SafetyIn Stock: 1065Z-15GD55-B7-K Datasheet

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Z-15GS55-B7-K

Omron Automation and SafetyIn Stock: 902Z-15GS55-B7-K Datasheet

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Z-15H2-B

Omron Automation and SafetyIn Stock: 1146Z-15H2-B Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the BZ-3R-A2 is determined by the following critical parameters:

Primary Compatibility Criteria:

• Circuit configuration must be SPDT
• Switch function must be On-Momentary
• Actuator type must be Round (Pin Plunger)
• Mounting type must be Chassis Mount
• Termination style must be Screw Terminal

Electrical Compatibility Criteria:

• AC voltage rating must be 125V minimum
• AC current rating must be 15A minimum
• DC voltage rating must support application requirements
• DC current rating must support application requirements

Mechanical Compatibility Criteria:

• Operating position tolerance must accommodate mechanical interface
• Pretravel, differential travel, and overtravel must be compatible with application actuation requirements
• Operating temperature range must encompass application environment

The substitute parts listed below meet these primary criteria while maintaining functional equivalence to the BZ-3R-A2 within specified electrical and mechanical parameters.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitutes (Highest Compatibility):

The Z-15G-B and Z-15H2-B represent the closest functional equivalents to the BZ-3R-A2. Both maintain identical operating position (0.625"), mechanical life rating (20,000,000 cycles), and chassis mount configuration. Z-15G-B matches the 15A AC current rating exactly, while Z-15H2-B operates at 10A AC. Both are manufactured by Omron Automation and Safety with active product status and RoHS compliance certification.

Secondary Substitutes (Mechanical Variation):

The Z-15GD-B7-K, Z-15GD55-B7-K, and Z-15GS55-B7-K maintain 15A AC rating and 20,000,000 cycle mechanical life but feature increased operating positions (0.846" to 1.110") and modified pretravel/overtravel characteristics. These variants are suitable where mechanical interface geometry permits the extended actuation distances. Z-15GD55-B7-K and Z-15GS55-B7-K provide IP62 ingress protection, appropriate for applications requiring sealed operation.

Higher Current Alternative:

The A-20GD-B7-K provides 20A AC capability, exceeding the BZ-3R-A2 specification. This part is suitable for applications where current margin is required. However, mechanical life is reduced to 1,000,000 cycles, and operating position extends to 1.030", requiring mechanical interface verification.

Compliance Considerations:

All substitute parts maintain RoHS compliance. Z-15GD-B7-K and Z-15H2-B carry REACH Affected designation, requiring verification against specific application regulatory requirements. All substitute parts are currently in active production status, ensuring long-term availability.

Temperature Range Limitation:

The BZ-3R-A2 operates across -55°C to 85°C. All substitute parts operate within -25°C to -15°C minimum temperature, representing a reduced lower temperature range. Applications requiring operation below -25°C require engineering evaluation for alternative solutions.

Frequently Asked Questions (FAQ)

Q: Can Z-15H2-B substitute for BZ-3R-A2 in all applications?

A: Z-15H2-B is functionally equivalent for AC applications at 10A or below. The 10A AC rating is lower than the BZ-3R-A2 15A specification. Verify that application current requirements do not exceed 10A AC. DC current capability is 2A versus 0.5A on the original part, providing improved DC performance. Operating position and mechanical life are identical.

Q: What is the significance of the different operating positions in the Z-series variants?

A: Operating position defines the plunger travel distance required to actuate the switch. Z-15G-B requires 0.625" travel (matching BZ-3R-A2), while Z-15GD variants require 0.846" and Z-15GS55-B7-K requires 1.110". The mechanical interface and actuator geometry must accommodate these travel distances. Shorter travel (Z-15G-B) is preferred where space is constrained; longer travel variants provide greater mechanical robustness in high-vibration environments.

Q: Are the IP62-rated variants (Z-15GD55-B7-K, Z-15GS55-B7-K) direct replacements?

A: IP62 rating provides sealed operation against dust and water spray, compared to IP00 (no protection) on standard variants. These are suitable for applications requiring environmental sealing. Mechanical parameters differ: Z-15GD55-B7-K has fixed 540gf operating force and 0.071" pretravel; Z-15GS55-B7-K has 250-350gf operating force and 0.015" pretravel. Verify that application actuation force and travel requirements align with the selected variant.

Q: Why does A-20GD-B7-K have lower mechanical life than other substitutes?

A: A-20GD-B7-K is rated for 1,000,000 mechanical cycles versus 20,000,000 on the BZ-3R-A2 and most Omron Z-series variants. This reflects different design architecture optimized for higher current capacity (20A AC). Applications requiring extended cycle life should select Z-series alternatives rated for 20,000,000 cycles.

Q: What is the impact of reduced DC voltage rating on substitute parts?

A: The BZ-3R-A2 is rated 125V DC; all substitute parts are rated 30V DC maximum. For AC-only applications, this is not a limitation. For DC applications, verify that circuit voltage does not exceed 30V. DC current capability varies: BZ-3R-A2 at 500mA, Z-15G-B and Z-15GD variants at 6A, Z-15H2-B at 2A, A-20GD-B7-K at 6A.

Q: Are there packaging differences between substitute options?

A: Z-15G-B is supplied in Tray packaging; Z-15GD-B7-K, Z-15GD55-B7-K, Z-15GS55-B7-K, Z-15H2-B, and A-20GD-B7-K are supplied in Bulk packaging. Packaging affects handling, storage, and procurement logistics but does not affect electrical or mechanical function.

Q: Can BZ-3R-A2 be used interchangeably with these substitutes in existing designs?

A: Direct interchangeability requires verification of: (1) current and voltage requirements within substitute ratings, (2) mechanical interface compatibility with operating position and travel specifications, (3) operating temperature range requirements (note reduced minimum temperature on substitutes), (4) DC voltage requirements (30V maximum on substitutes). Physical form factor, mounting footprint, and terminal configuration are identical across all listed parts.