Harsh environment connectors are designed for conditions such as water spray and intermittent water submission (IP67). ‘Harsh Harsh’ environment connectors are however designed for extended temperatures from -55ºC to +150ºC and/or deep submersion (>5000 feet).
Harsh environment connectors that are properly specified will meet or exceed typical application needs. Since levels of sealing protection, temperature ranges and environmental specifications vary from application to application, it is important to design at the level appropriate for the application.
Typical environmental concerns include dust, spray and moisture exposure, water submersion and depth, temperature range, fluids, gas environments, pressure, shielding, UV and radiation. Harsh environment connectors must therefore be chosen with the correct combination of protective features after examining the application.
The typical sealed connector is rated for IP67 and has a temperature range of -40ºC to +85ºC. Industry standards are influencing the ratings of many plastic connectors pushing them to achieve a rating of IP68 (NEMA 250 6P) for sealing, with a temperature range of -40ºC to +105ºC. Additionally, requirements for UV inhibitors in the plastic components and extended life are normal today given that connectors are being used on rooftops, buried in the ground and exposed to temperature cycles for many years with the typical goal of 20 years of service life.
These conditions require the selection of the right plastic materials to provide strength and flexibility to the connector. Depending on the connector design, the plastic materials are typically glass filled for strength or no glass for flexibility needed for cable clamp fingers or coupling rings.
Additionally, the plastic materials need to be impervious to moisture pick-up in order to diminish the reduction in insulation resistance caused by moisture ingression in plastics. Plastics exposed to sunlight usually need to have UV inhibitors to reduce the plastic degradation over time.
Apart from the housing materials, the selection of the elastomer materials for sealing is also important based on temperature and set characteristics. The connector design then adds features that allow proper functioning in the connector assembly including the proper amount of elastomer squeeze on sealing interfaces.
Once the design is validated using FEA (finite element analysis), prototypes may be made for further validation or for customer feedback. MOLDFLOW (or any other tooling creation analysis tool) is then utilised to ensure feasibility and optimisation of the design in the tooling creation process. Validation testing is done after the pilot run, before the connector is released into the market.
Harsh environment connectors are available in many types ranging from plastic to metal, round and rectangular, single through multiple conductors, and covering a variety of special environments. Connectors must always be selected based on application requirements.
Harsh environment connectors are available from Clarke & Severn Electronics