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CPI Military Switching Products

CPI Waterproof and Thermal Switches for the Military

CPI - Keeping Military Personnel Safe for almost 80 Years

Unless you are a rabid CPI company history buff, (like us) you may not know that CPI’s original switch parts developed back in 1946, were thermal switches designed for transport vehicles and tanks for the US Army. Back then technology was all analog and detection mechanisms really depended on the reliability and durability of switches, which acted as sensors or activators for a variety of military vehicle systems.

Our switches were so successful and reliable, that over time the Navy and Air Force and even NASA got involved. They all have also adopted CPI’s high durability thermal or waterproof switches for aircraft and naval vessels. Applications include everything from door or hatch open detection to oil temperature monitoring applications for our M2 series thermals. Literally hundreds of applications for the military. Some so secret that you’ll just have to take our word for it…

While CPI thermal and waterproof switches have seen literally thousands of upgrades and improvements over the years, there are a few things that haven’t changed at all.

  • Our design and manufacturing philosophy is 100% about the quality and longevity of our switches and sensors in challenging operational environments be they Military or Industrial while keeping cost competitive in production quantities.
  • We conform to all appropriate Mil-Spec’s governing our parts and provide testing and paperwork.
  • We were, and still are, 100% designed and manufactured in the USA.

CPI Military Grade Switch Applications In 2023

Waterproof Momentary Switch by CPI
CPI B2 Series Waterproof Pendant Switch

Fast forward the better part of a century and the world has gone digital. Some applications that used a standalone switch have gone the way of cheap sensors and microcontrollers. And yet for sheer survivability and operational lifetime, CPI switches remain one of the only USA made brands that can solve certain problems reliably.

Both our thermal and waterproof switches continue to find hundreds of uses in Military vehicles. In waterproof switches our commercially available B2 Series switch is typically used within a customized mounting bracket design to fit the operating requirements of the application. Customer specified MS connectors are provided with the switch to make a completely waterproof product. Our thermal switches are known for their reliability, immunity to vibration and the extreme operating temperature range from -65F to 1750F. Other thermal switches focus only on the hot but our switches also operate in extreme cold, allowing unique uses such as turning on a heater to prevent the failure of other components in the Navy’s Phalanx Anti-Missile System.

Below is a summary of the characteristics of our switches that have made them so perfect for robust standalone detection applications over the years.

CPI Sealed Waterproof Switches

CPI Thermal Switches

  • Completely Submersible sealed switches that conform to MS39058 and other Mil Specs.
  • Unmatched precision and the most rapid response time available in a thermal switch.
  • Protected switches withstand high temperatures inside engine compartments or under a chassis, and don’t freeze up when its freezing. 
  • Three families of thermal switches operating in different temperature ranges, form factors and operational characteristics up to 1750F

Electrical ratings:

  • Electromechanical Endurance: 100,000 to 5 million cycles (depending on configuration)
  • Operating temperature range: -65F to 221F, depending on item; (J4 Series: -50ºF to 302ºF)
  • Environmental resistance: Excellent resistance to both high and low temperatures, acids, alkalies, salt spray, sand, dust and fungus

Electrical ratings:

  • SnapStats: (28VDC/120VAC) 5 amps resistive, 3 amps inductive. Gold contacts available special order.
  • PlugStats (bimetal): (28VDC/115VAC) 2 amps resistive, ½ amp inductive
  • Rod & Tube: (28VDC/115VAC) 1.5 amps resistive, 1/2 amp inductive temps from 750F to 1750F

Waterproof Switch APPLICATIONS


  • E1002-501 (USATAC 12339494) / engine kickdown – HMMWV
  • D1011-501 (USATAC 11669772) / cold-start ether injection – M939 5-ton truck
  • E2038 (USATAC 11669094) / brake light switch – M939 5-ton truck `
  • K1013-501 (USATAC 11669679) / 2- to 6-wheel drive shifter – M939 5-ton trucks
  • B2 momentary within custom molded housing
  • E1344-501 (Oshkosh) / idle validation – LVSR & HEMTT
  • D1021-538 (Oshkosh) / spare tire hoist on/off – FHTV PLS
  • E1117-525 (Oshkosh) / dumpster stow position limit for roll-off
  • K1111-501 (Oshkosh) / fuel door detection switch – HEMTT fuel truck
  • J4401-514 (BAE-Sealy/USATAC 12505576) / cab tilt position – LTAS
  • J4 Neutral Safety Detection Chosen for Military Humvee by Oskosh.
  • J4001 / J4002 (General Dynamics) / seat switch, operator presence detection – Pandur
  • AD105-503 (USATAC 12338599) / engine HOT thermal switch – HMMWV
  • Standard AD threaded switch with waterproof MS plug connectors and wire markers.
  •  M1002-538 (Textron MLS) / view screen anti-freeze protection – ASV standard M1 Series thermal switch with added screw terminals for easy, non-solder connection
  • M2003-502 (Honeywell) / lube oil overheat switch in gas turbine engine – M-1 Abrams Tank. Off-the-shelf M2 Series with gold contacts
  • M2146-503, -504 (BAE – Leicester) / cooling system, water anti-freeze switch for startup – Terrier. M2 switches with commercially available BSPP thread mounting adaptor
  • AD053-508 (Supacat) / coolant system, caution and warning indication – HMT 400 dual-temperatures to indicate two system conditions to operator
  • Navy Phalanx Program – Our AC006-501 will trigger when ambient temperature in the electronics bay drops below a threshold activating a heating circuit.

An Engineering Team Standing by to Qualify your Military Application.

As a long time partner to military subs and OEM’s, we’re pretty darn familiar with the qualification process and have the experience and capability to perform most kinds of relevant testing. Since 1946, CPI has been providing thermal and waterproof switches to the military & law enforcement industries from tanks to armored personnel carriers to Submarines. We have over 100 National Stock Numbers (NSN), QPL, USATAC and MS items in our catalog.

Consider the following characteristics of the CPI Military Product offering:

MIL-Compliant Features

  • Switches meet or exceed MS 39058, MIL-STD-202, MIL-F-13927, MIL-S-13484 (waterproof); MIL-STD-810 (thermal)
  • Operating temperatures down to -65°F
  • Commercial and MIL sealed terminations available
  • Custom ID tags and marking available
  • All products are classified COTS

Please call or contact the CPI engineering team to discuss your harsh duty, high reliability switch or sensor application today.

Make The "Switch" to CPI

If your momentary switch application demands high performance, we think you should demand CPI. Please call us today to speak with our engineering team about your needs.

(973) 887-9400