Honeywell 21SM284 Snap Action Switch SPDT Equivalent & Substitute Parts

Part Overview

The Honeywell 21SM284 is an active-status snap action switch with SPDT (Single Pole Double Throw) circuit configuration, rated for 5A at 115V AC and 28V DC. This chassis-mount switch features a round pin plunger actuator with solder lug termination and is designed for on-momentary switching applications. The part is RoHS compliant and maintains unlimited moisture sensitivity level (MSL 1) rating.

Equivalent and substitute parts are identified to support component availability, supply chain flexibility, and design alternatives where electrical and mechanical parameters align within acceptable tolerances for SPDT snap action switch applications.

Substiute Parts

21SM284

Honeywell Sensing and Productivity SolutionsIn Stock: 122621SM284 Datasheet

Current PartRFQ

MS0850500F060S1A

E-SwitchIn Stock: 1035MS0850500F060S1A Datasheet

SimilarRFQ

MS0850500F080S1A

E-SwitchIn Stock: 1289MS0850500F080S1A Datasheet

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MS0850500F250S1A

E-SwitchIn Stock: 1435MS0850500F250S1A Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the Honeywell 21SM284 are identified from the E-Switch MS0850500 series based on the following substitution criteria:

Core Electrical Compatibility:

• SPDT circuit configuration maintained across all substitutes
• 5A current rating (AC) consistent with primary application requirements
• 125V AC voltage rating exceeds the 115V AC requirement of the main part
• On-momentary switch function preserved

Mechanical Compatibility:

• Round pin plunger actuator type identical to main part
• Chassis mount configuration maintained
• Solder lug termination style consistent
• Operating position within 0.335" (8.5mm) aligns with 0.330" (8.4mm) specification

Regulatory & Environmental:

• RoHS3 compliance meets or exceeds RoHS requirement
• MSL 1 rating matches unlimited moisture sensitivity level
• REACH unaffected status consistent with main part
• ECCN EAR99 classification identical

Substitution Variants: Three E-Switch models are qualified as substitutes, differentiated by operating force specification:

• MS0850500F060S1A: 60gf operating force
• MS0850500F080S1A: 80gf operating force
• MS0850500F250S1A: 250gf operating force

Parameter Comparison

Engineering Selection Recommendations

Compliance & Regulatory Alignment: All substitute parts maintain REACH unaffected status and EAR99 ECCN classification consistent with the Honeywell 21SM284. E-Switch MS series parts carry ROHS3 compliance, which exceeds the RoHS requirement of the main part. MSL 1 rating is preserved across all options, supporting unlimited moisture sensitivity applications.

Electrical Performance: E-Switch substitutes are rated for 125V AC, providing 10V margin above the 115V AC specification of the main part. The 5A current rating is maintained. DC voltage rating is not specified for E-Switch parts; applications requiring 28V DC operation should confirm compatibility with E-Switch technical documentation.

Mechanical & Operational Characteristics: Operating force varies across the three E-Switch models (60gf, 80gf, 250gf) compared to the Honeywell specification of 141gf. Selection should be based on specific actuator force requirements for the application. Operating position tolerance is within 0.005" (0.1mm) of the main part specification. Pretravel increases from 0.030" to 0.043", representing a 0.013" (0.3mm) difference.

Lifecycle Considerations: E-Switch MS0850500 series parts specify 1,000,000 mechanical life cycles, substantially exceeding the 80,000 cycle rating of the Honeywell part. Electrical life is rated at 50,000 cycles for E-Switch parts.

Temperature Operating Range: E-Switch substitutes operate within -25°C to 85°C, which is narrower than the Honeywell specification of -55°C to 125°C. Applications requiring extended low-temperature operation below -25°C or high-temperature operation above 85°C should retain the Honeywell 21SM284.

Frequently Asked Questions (FAQ)

Q: Can E-Switch MS0850500 series parts directly replace the Honeywell 21SM284 in all applications?

A: E-Switch MS0850500 series parts are electrically and mechanically compatible for SPDT snap action switch applications within the specified operating temperature range of -25°C to 85°C. Applications requiring operation below -25°C or above 85°C, or DC voltage operation at 28V, require confirmation of compatibility with E-Switch technical specifications.

Q: What is the significance of the three different operating force variants in the E-Switch MS0850500 series?

A: The three E-Switch models differ in operating force specification: MS0850500F060S1A (60gf), MS0850500F080S1A (80gf), and MS0850500F250S1A (250gf). Selection depends on the actuator force requirement of the specific application. The Honeywell 21SM284 specifies 141gf operating force; the 80gf variant provides the closest match, while the 60gf and 250gf variants serve applications with lower or higher force requirements respectively.

Q: Are there differences in pretravel between the main part and substitutes?

A: Yes. The Honeywell 21SM284 specifies 0.030" (0.8mm) pretravel, while E-Switch MS0850500 series parts specify 0.043" (1.1mm) pretravel. This 0.013" (0.3mm) difference should be evaluated for applications with tight mechanical tolerances or specific actuation sequencing requirements.

Q: What is the inventory status for each part?

A: Honeywell 21SM284: 1116 pieces in stock. E-Switch MS0850500F060S1A: 997 pieces in stock. E-Switch MS0850500F080S1A: 1250 pieces in stock. E-Switch MS0850500F250S1A: 1404 pieces in stock.

Q: Do all parts meet RoHS and REACH compliance requirements?

A: Yes. The Honeywell 21SM284 is RoHS compliant and REACH unaffected. All E-Switch MS0850500 series substitutes are ROHS3 compliant and REACH unaffected, meeting or exceeding regulatory requirements.

Q: What is the mechanical life expectancy difference between the main part and substitutes?

A: The Honeywell 21SM284 specifies 80,000 mechanical life cycles. E-Switch MS0850500 series parts specify 1,000,000 mechanical life cycles, providing approximately 12.5 times greater mechanical durability.

Q: Are DC voltage ratings specified for E-Switch substitutes?

A: DC voltage ratings are not specified in the provided technical data for E-Switch MS0850500 series parts. The Honeywell 21SM284 is rated for 28V DC. Applications requiring DC operation should consult E-Switch technical documentation to confirm DC voltage compatibility.