The Design of Waterproof Connectors
If an electrical connection needs to be protected from the environment in which it operates – due to water, dust, or both – a sealed connector is typically selected for the job. Two types of sealing are available: (1) sealing for ingress protection, or IP, and (2) hermetic sealing, where the contacts are sealed against air and gases. Sealing for IP is common in many applications, but hermetic sealing is typically reserved for more restrictive applications, such as those used by space and satellite industries.
When people talk about waterproof connectors, they’re generally referring to connectors that are constructed and manufactured in such a way that water and dust cannot pass through the connector. These connectors protect the sensitive electronics inside enclosures.
Understanding IP Ratings
Ingress protection (IP) ratings convey a connector’s level of protection against solids and liquids, such as dust and water. They’re used by the National Electrical Manufacturers Association (NEMA), Society of Automotive Engineers (SAE), and International Electrotechnical Commission (IEC) 60529 Standards, amongst others.
Each IP rating is composed of two numbers. The first number conveys the level of protection provided against the ingress of solid foreign objects and the access to hazardous parts. The second number conveys the level of protection provided against the ingress of liquid. The higher the numerals, the greater the level of protection.
For example, all Positronic waterproof connectors have IP ratings that begin with 6, which is the highest level of solid particle protection. An IP rating that includes 6 as its first numeral indicates that the connector is dust-tight, meaning there is no ingress of dust. For the second numeral, most Positronic waterproof connectors are 5 and above, offering the following degrees of protection:
- IP65: IP65 connectors provide protection against basic pressure water jets. Water projected by a nozzle under stated conditions should have no harmful effect on the system.
- IP66: IP65 connectors provide protection against high-pressure water jets. Water projected by a high-pressure nozzle under stated conditions should have no harmful effect on the system.
- IP67: IP67 connectors provide protection against immersion in water under stated conditions of pressure and time. The immersion may be up to one meter in depth.
- IP68: IP68 connectors provide protection against immersion in water for a duration and at a depth and pressure specified by the manufacturer. The immersion must be one meter or more in depth. Some IP68 connectors are designed for continual use and can safely function underwater for years.
- IP69K: IP69K connectors provide protection against close-range, high-pressure, high-temperature spray-downs (water jets).
Although you may be tempted to select or design a connector with an IP rating above your application’s requirements, this is not recommended. In regard to ingress protection, over-designing a connector can be costly. In fact, simply moving from an IP65 rating to an IP67 rating can double the price of a connector. This occurs because a higher IP rating may require features like a stronger seal, interfacial seals, or the addition of grommets, which may necessitate higher performance materials and more assembly time.
Positronic offers a wide variety of waterproof, hermetic, and sealed environmental connectors with varying IP ratings. If you don’t find the ideal connectivity solution in their catalog, consider creating a custom connector.
Waterproof Connectors from Positronic
Within the specialty market of hermetic connectors, Positronic produces several series, including the XAVAC Series and SAVAC Series. These connectors are frequently used in the testing of space-bound equipment. They can connect electronic devices in thermal vacuum chambers, which simulate environmental conditions in space, with test instruments that are not vacuum compatible, which are kept on the outside of the test chamber. Positronic hermetic connectors are tested to ensure a helium leak rate less than 5 x 10-9 mbar x l/s under a vacuum of 0.015 mbar. In addition, their materials and finishes, as well as their technical characteristics, conform to MIL-DTL-24308 and Goddard specifications. To learn more about their hermetic connectors, view this webinar: Hermetic Connectors Are Essential in the Development of Space-Bound Equipment.
Waterproof D-Sub Connectors
Positronic waterproof D-subminiature connectors include the WD Series (standard density), WDD Series (high density), and EVD Series (free cable to military-grade, M24308 performance standards). Sealed to prevent the ingress of dust and water, these connectors suit a wide range of applications, from commercial aircraft to military and industrial. They’re rated IP67 and are available with waterproofing features like the following:
- Corrosion-resistant stainless-steel shells
- Cul-de-sac blind hole fasteners
- Angle brackets
- Push-on fasteners
- Panel mount sealing plate
- Printed board terminations
- Interfacial seals
- Protective covers
- Fixed jackscrews
Positronic also offers a unibody D-sub design within the WD series. Because the panel mount and connector are all one piece, this connectivity solution greatly reduces the amount of secondary sealing required and is easier to assemble. It’s a popular, economical option for applications requiring sealed connectors.
Waterproof Circular Connectors
Front Runner connectors are made from thermoplastic elastomer, nylon, and glass-filled polyester – lightweight materials that make them ideal for aircraft environments. They’re rated IP67, and they’re able to accommodate signal and power contacts. Because they lack metal shells but do feature special seals, these durable connectors are a popular choice in a variety of applications.
The Baby King Cobra Series features cost-effective, IP65-rated designs. Two different configurations of these miniature form factor connectors are available, utilizing solid-machined contacts. Baby King Cobra connectors are used in applications where water is dripping or the environment is moist.
Finally, the small yet powerful Talon Mini Series was designed for a specific application: hydraulic actuation of business-class seats in commercial aircraft. These metal shell, IP65-rated circular connectors are available in cable-to-cable and cable-to-panel designs. Their interfacial seal makes them waterproof in the mating area, which is necessary to protect against spilled drinks in the passenger area.
Custom Waterproof Connectors
Positronic engineers can modify any Positronic connector series to create a waterproof solution. For example, they recently designed a custom waterproof Goldfish Series power connector for battery packs used in the medical industry. Not only did the connector have to meet IP22 (a unique, small-dripping requirement), but also it had to have a very precise mating/unmating force and provide at least 1,500 mating cycles. Positronic was able to design and deliver an ideal, customized solution.
Where Are Waterproof Connectors Used?
Waterproof connectors are used in numerous industries: healthcare, defense, aerospace, transportation, outdoor electronic equipment, and more. Positronic has designed waterproof connectors for a variety of applications, as you can see in the following examples:
- Irrigation Systems: Positronic assisted a client that required a connector for solar-powered remote irrigation equipment. One of their IP67-rated BKC series circular connectors offered sufficient corrosion resistance in a lightweight package.
- Medical Battery Packs: A client requested a custom power connector system to interface between lithium-ion battery packs and portable oxygen-delivery devices designed for patients with sleep apnea. Positronic engineers ruggedized their small, lightweight Goldfish series to meet the IP requirements. The solution was reliable and offered a high number of mating cycles, allowing it to last longer in the field.
- Medical Laser System: Another client in the medical industry required a waterproof connector for a laser system used for DNA sequencing and spectroscopy. The connector had to offer protection from liquid splashed from any direction. The IP67-rated WD and EVD D-subminiature connectors were selected for the job, as they’re reliable and proven to resist spillage and splashing.
- Bus Surveillance Equipment: A commuter bus client required a connector for surveillance equipment kept under drivers’ seats that had to be protected during the buses’ evening cleaning routine (which involved a high-pressure hose). A WD series connector with an IP67 rating was an ideal solution, allowing the fleet equipment to withstand nightly showers.
- Fighter Jets: A client in the defense industry sought a durable connector that could operate in a harsh environment: on the wings of fighter jets. The connector also needed to withstand high-power cleanings involving strong solvents. The Positronic EVD Series D-sub, with its IP67 protection, provided reliability in this demanding application.
- Electric Wakeboards: For its fleet of electric wakeboards, a client needed a connectivity solution with IP66 protection and press-fit and solder cup terminations. Positronic designed a custom connector based on the Scorpion series that also included custom contacts.
Going forward, Positronic will expand its waterproofing capabilities to assist with more applications around the world – from rugged, outdoor applications to mission-critical military and aerospace applications. To learn more about the design challenges and engineering requirements of waterproof connectors, please check out the webinar: Waterproof Ruggedized Connectors for Secure Connections.
ESI is the local rep in Ohio, W. PA, W. VA, Michigan, Kentucky and Indiana for Positronic. We invite you to reach out for samples and information.