The electromechanical devices known as “connectors” are found in almost every modern electrical and electronic system, ranging from industrial machinery and automotive wiring to consumer electronics and telecoms equipment.
Engineers and buyers certainly need to think about such aspects as pin count and voltage rating when they’re attempting to determine the right connectors for a given application. However, there’s at least one other crucial element that they might not immediately give so much consideration: the connector’s housing material.
Whether you decide in favour of plastic or metal housing material in your search for the most suitable connectors for your project could have significant implications for performance, cost, longevity, and safety.
What Is a Connector Housing?
The “housing” of a connector is the outer shell that protects the contacts and internal connection points. This part of a connector helps provide mechanical protection, electrical insulation, environmental sealing, strain relief, and in some cases, electromagnetic interference (EMI) shielding.
Connector housings can be manufactured from engineered plastics, metal alloys, or hybrid combinations of these materials.
The range of connectors available at RS Online includes components with both plastic and metal housings. These encompass such options as printed circuit board (PCB) connectors, industrial circular connectors, radio frequency (RF) and coaxial connectors, heavy-duty industrial connectors, and terminal blocks.
Plastic Connector Housings: Lightweight, Cost-Effective, And Versatile
Plastic housings for connectors tend to be made from engineering polymers such as Nylon 66 (PA66), polybutylene terephthalate (PBT), or polycarbonate. These materials have gained popularity across a range of applications in recent years.
The key advantages of plastic connector housings include that they’re:
- Lightweight, which makes them ideal for applications where weight savings matter, such as portable equipment, drones, and automotive projects
- Relatively inexpensive to produce and purchase, which makes them attractive for high-volume or budget-sensitive projects
- Resistant to corrosion and moisture, so they can be counted on to maintain reliable performance in humid, saltwater, or chemical environments without rusting
- Naturally non-conductive, thereby lessening the risk of shorts and often eliminating the need for additional grounding
- Easier to mould into complex shapes than metal, with good ergonomics and colour options.
Plastic does, of course, come with some limitations as a connector housing material. It doesn’t offer metal’s level of mechanical strength and impact resistance, so if it is subject to heavy abuse or extreme temperatures, it can be more prone to cracking.
Some plastics may also degrade over very long periods in direct sunlight or high-heat environments unless flame-retardant or ultraviolet (UV)-stabilised grades are used.
Metal Connector Housings: Rugged, Shielded, And Built for Demanding Conditions
When professionals require maximum durability from their connectors, it is metal housings that are typically the go-to choice. These connector housings are commonly made from aluminium, stainless steel, or zinc alloys.
Metal connector housings offer a number of benefits, including that they’re:
- Highly resistant to impact, vibration, pulling, twisting, and extreme temperatures, thanks to their superior mechanical strength and durability
- Effective at shielding for EMI and radio frequency interference (RFI), due to the metal enclosure acting as a Faraday cage
- Generally more resistant to fire than plastic; metal connector housings typically have higher melting points, and they can be depended on to maintain their structural integrity even in punishing conditions
- Likely to have a longer service life than plastic in demanding environments such as factories, railways, or construction sites.
As with plastic, metal connector housings are limited in certain respects. Not only are they more expensive than plastic housings upfront, but their relative heaviness also pushes up the overall system weight.
Metal housings can also suffer from corrosion, unless stainless-steel or properly coated or plated versions are used.
In Summary, Then: Which Connector Housing Material Should You Choose?
As you seek to determine the right connectors for your projects, there will be a lot of specifications for you to whittle down. As far as the housing material is concerned, though, here are some useful “rules of thumb”:
- Choose plastic housings if your project calls for a lightweight and cost-sensitive solution for a relatively clean and dry environment
- Opt for metal housings if your application requires high mechanical durability, protection against electrical noise, or resistance to extreme temperatures.
Taking such factors into account as the industry or environment the connectors will be used in, your required current and voltage ratings, and whether waterproofing or ingress protection (IP) ratings are a priority, will further aid your efforts to settle on the right choice of connectors.
