Recently, the aftermarket automotive industry has started using this new term when marketing wiring harnesses, sensors and electrical components. This leads consumers to believe that regular automotive products are "MIL-SPEC" because they are marketed and sold as such. This post will hopefully clear some of the air surrounding the term, and it's use. This is only meant as a beginner’s guide. We have been dealing with various MIL-SPEC components for decades now, and rest assured you won't be able to learn this all in one article! More can be learned by browsing the topic online, especially through .mil websites. Here are some links:
Before we get into true MIL-SPEC specific parts, let's take a look at the term itself, and it's definition. The United States military uses standardization in almost everything it does. Having things standardized allows commonality, reliability, compatibility between systems, ensuring products meet certain requirements and overall interoperability in defense related objectives. One benefit that the general consumers can take advantage of is the pricing on those parts.
When a connector is truly MIL-SPEC, more times than not the US Government owns the rights to the design, allowing other companies to compete in the market to make and sell those parts to the US DoD and its contractors.
You might see other terms like MIL-SPEC used on occasion. They are likely the formal terms being used. Some examples are:
MIL-STD (defense standard)
MIL-DTL (defense detail spec)
MIL-PRF (defense performance spec)
MIL-SPEC (defense specification).
The use of "milspec" is just the informal way of signifying that something meets a certain Military Standard (MIL-STD) or Military Specification (MIL-SPEC).
Two examples of MIL-STD's used in our industry that we deal with often are MIL-STD-461F and MIL-STD-810G. 461 is the standard on how to test electronics for electromagnetic compatibility and 810 is a broad range standard of environmental conditions. These standards are used by the government when selecting hardware and components for their vehicles, vessels, aircraft and other specialty units. The cost to test one piece of hardware for the most common portions of MIL-STD-461F starts at $25,000USD and takes approx. 2 weeks to complete on average. So, when people refer to their wiring harness as "MIL-SPEC", or a company tries to tell you that their electronics are "MIL-SPEC", you now have an idea what that requires, and what that means!
"WHAT ARE MIL-SPEC CONNECTORS?"
Connectors used by U.S. Department of Defense were originally developed in the 1930s for severe aeronautical and tactical service applications, and the Type "AN" (Army-Navy) series set the standard for modern military circular connectors. These connectors, and their evolutionary derivatives, are often called Military Standard, "MIL-STD", or (informally) "MIL-SPEC" connectors. They are now used in aerospace, industrial, marine, and even automotive commercial applications. Connectors usually consist of a mating pair (plug and receptacle) each equipped with male (pin) or female (socket) contacts; note that at least one of the connector halves, or its contacts, should be floating to minimize mechanical stresses.
Electrical connector contacts are typically Beryllium copper (BeCu) or Phosphor bronze which is then plated with gold or some other non-corrosive, highly-conductive metal. The contacts are contained by a dielectric insulator (Mansol Glass Preform (i.e.., the insert)) and are housed in an enclosure (i.e.., shell), that is often die-cast aluminum and plated or anodized for corrosion protection. The contacts may be captive or removable using a special tool. The electrical connection into the system at the contact terminal is either a soldered or crimped connection. The seal between the shell and insert may be moisture resistant or a hermetic seal. The inserts in each connector half must be oriented for correct mating, and the shell or insert usually contains a keying feature to prevent mis-mating that could damage the connector or result in an electrical problem. Cable clamps and other mounting hardware may be provided, and the mated halves are usually secured by a locking mechanism to prevent disengagement.
We offer connectors that are MIL-DTL-38999 and MIL-DTL-26482 compliant. These consist of four different classes of miniature, high density, bayonet, breech coupling or threaded, circular, environment resistant, electrical connectors that use removable crimp contacts that function between -65C to 200C in the harshest of places.
"WHY ARE YOUR MIL-SPEC CONNECTORS BLACK, AND EVERYONE ELSE SELLS NICKEL
This is simple, our clients require them! Each customer has a different need, and of the majority of customers we sell to, more than 90% of them either require or benefit from black zinc nickel over cadmium zinc or even electroless nickel. If your only job requirement is esthetics, then you can pick silver, black or olive drab green finish. However for those of you who have environmental conditions to deal with, or compatibility concerns, then most likely the zinc nickel is going to meet and exceed your requirements. The downside to zinc nickel is the cost when compared to the other options.
Here is a breakdown of the three most common finishes:
Cadmium Zinc (olive drab/green) - For a long time the standard of plating to protect against the elements. Some complain that the olive green outer coating will wear easily giving the illusion that the aluminum of the connector body is showing when in fact that is the cadmium showing through. Cadmium Zinc can withstand 500-hour salt spray. Cadmium however is a highly toxic carcinogen and can cause cardiovascular issues to humans. The military has been searching for an alternative for decades, and has started to move to zinc nickel over the past decade.
Electroless Nickel - Conforms to ATSM B733 standard. For some, an appealing finish for their cabling requirements. It has the best wear resistance of the finishes offered by manufacturers, however it has very poor galvanic compatibility with Cadmium Zinc finish. It is only rated to 48 hours of salt spray. This is the most common connector finish type in the automotive market due to it's lower cost.
Aluminum Black Zinc Nickel - Conforms to ATSM B841 standard, and is MIL-DTL-38999, MIL-DTL-26482 and AS85049 compliant. This finish is fully compatible with other cadmium zinc plated connectors, and is rated to withstand 500 hours of salt spray (1000 hours on backshells). It features a non-reflective finish and RoHS compliance.
See our full range of MIL-SPEC connectors here - MIL-SPEC CONNECTORS