PartsTable
Technical Data Sheet
PartsTable / MRO / 21S4
21S4 ✓ Verified by PartsTable
— · MRO · MRO_GENERAL
WHAT YOU NEED TO KNOW
Verify manufacturer and server generation compatibility Check if Option PN or Spare PN — same part, different channel
Confirm exact part number — similar PNs may be different parts
PRODUCT OVERVIEW

The SWITCH,THERMOSTATIC is a the manufacturer industrial component. Key specifications include overall_width: 0.660 INCHES NOMINAL IN, terminal_type: TAB, SOLDER LUG, overall_height: 0.305 INCHES NOMINAL IN, overall_length: 1.125 INCHES NOMINAL IN, mounting_method: BRACKET(S), special_features: TWO 0.147 IN. DIA MTG HOLESSPACED 0.875 IN.

C TO C IN. This product is currently in active production with full OEM support. This part is cataloged in the Federal Logistics Information System (FLIS) under NSN 5930-00-998-4246, indicating validated use in U.S.

government and defense logistics supply chains. Available through authorized enterprise resellers and TPM (Third Party Maintenance) channels. Verify compatibility with your specific system configuration before ordering.

WHERE IT FITS
MRO→ MRO_GENERAL→ 21S4
NSN: 5930-00-998-4246
FSC: 5930
CAGE: 99872 — ENTRON INDUSTRIES LIMITED PARTNERSHIP DBA ENTRON INDUSTRIES PROPERTY DIV (USA)
SPECIFICATIONS
overall_width0.660 INCHES NOMINAL IN
terminal_typeTAB, SOLDER LUG
overall_height0.305 INCHES NOMINAL IN
overall_length1.125 INCHES NOMINAL IN
mounting_methodBRACKET(S)
special_featuresTWO 0.147 IN. DIA MTG HOLESSPACED 0.875 IN. C TO C IN
contact_adjustabilityACTUATION POINT NOT ADJUSTABLE
contact_action_stimulusINCREASE
contact_stimulus_rating158.00 ACTUATION POINT NOMINAL DEGREES FAHRENHEIT AND 138.00 DEACTUATION POINT NOMINAL DEGREES FAHRENHEIT
temp_sensing_element_typeINTERNAL SENSOR
contact_load_current_rating1.0 AMPERES RESISTIVE LOAD SINGLE VOLTAGE
nonpile-up_contact_arrangement1 POLE, SINGLE THROW, NORMALLY OPEN, MOMENTARY ACTION
NSN5930-00-998-4246
COMPONENT DIAGRAM
COMPONENT MAIN IC EDGE CONNECTOR No detailed specs available SWITCH,THERMOSTATIC TITLE COMPONENT PN 21S4 MFR SWITCH,THERMOSTATIC
KEY FEATURES
•
TERMINAL TYPE: TAB, SOLDER LUG
•
CONTACT ACTION STIMULUS: INCREASE
•
CONTACT STIMULUS RATING: 158.00 ACTUATION POINT NOMINAL DEGREES FAHRENHEIT AND 138.00 DEACTUATION POINT NOMINAL DEGREES FAHRENHEIT
•
CONTACT LOAD CURRENT RATING: 1.0 AMPERES RESISTIVE LOAD SINGLE VOLTAGE
•
CONTACT ADJUSTABILITY: ACTUATION POINT NOT ADJUSTABLE
•
CONTACT VOLTAGE RATING IN VOLTS: 125.0 AC AT SEA LEVEL SINGLE VOLTAGE
TECHNICAL CHARACTERISTICS (FLIS)
TERMINAL TYPETAB, SOLDER LUG
CONTACT ACTION STIMULUSINCREASE
CONTACT STIMULUS RATING158.00 ACTUATION POINT NOMINAL DEGREES FAHRENHEIT AND 138.00 DEACTUATION POINT NOMINAL DEGREES FAHRENHEIT
CONTACT LOAD CURRENT RATING1.0 AMPERES RESISTIVE LOAD SINGLE VOLTAGE
CONTACT ADJUSTABILITYACTUATION POINT NOT ADJUSTABLE
OVERALL WIDTH0.660 INCHES NOMINAL IN
SPECIAL FEATURESTWO 0.147 IN. DIA MTG HOLESSPACED 0.875 IN. C TO C IN
CONTACT VOLTAGE RATING IN VOLTS125.0 AC AT SEA LEVEL SINGLE VOLTAGE
OVERALL LENGTH1.125 INCHES NOMINAL IN
MOUNTING METHODBRACKET(S)
VERIFIED SUBSTITUTES & CROSS-REFERENCES 9
240-9004-009Interchangeable
interchangeable cross-reference
interchangeable
TC1830Interchangeable
interchangeable cross-reference
interchangeable
A409Interchangeable
interchangeable cross-reference
interchangeable
A409TAN16426Interchangeable
interchangeable cross-reference
interchangeable
BLS4R09NInterchangeable
interchangeable cross-reference
interchangeable
01-0450685-00Interchangeable
interchangeable cross-reference
interchangeable
LIFECYCLE
StatusACTIVE
AvailabilityOEM and secondary market
RoHS CompliantEAR99Not HAZMAT
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FREQUENTLY ASKED QUESTIONS
What is 21S4?
21S4 is a SWITCH,THERMOSTATIC. It is classified as a MRO (MRO_GENERAL).
What parts can replace 21S4?
There are 9 known substitutes for 21S4: 240-9004-009, TC1830, A409 and 6 more. Substitute compatibility should be verified for your specific system.
What is the NSN for 21S4?
21S4 is cataloged in the Federal Logistics Information System (FLIS) under NSN 5930-00-998-4246. This indicates validated use in U.S. government and defense supply chains.
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✓ Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
PartsTable Design LLC · partstable.com
Last verified: July 2026