Rugged Interconnects for Harsh Environments eBook

MATERIAL SELECTION AND ENCLOSURE DESIGN Most outdoor enclosures on the market are made from metal (aluminum, stainless steel), plastics (outdoor-rated polycarbonate grades, glass-filled polybutylene terephthalate [PBT]), or fiberglass. Each has its benefits and drawbacks to corrosion and chemical resistance, mechanical strength, thermal/ electrical properties, and cost. Evaluating areas most important to the specific application will help narrow the material selections. When the equipment will be exposed to saltwater, stainless steel or plastic enclosures are chosen for their corrosion resistance. However, polycarbonate enclosures provide a lower applied cost and excellent impact resistance compared to other polymers. Material that is UL 746c f1-rated for outdoor applications is often a good choice. Ambient temperature with direct sunlight can be an important consideration. Black housings will absorb more heat. To mitigate an exaggerated temperature rise, consider using a lighter-colored material. DEGREE OF PROTECTION While materials are a focus point for enclosures, design features should not be overlooked. Ingress protection for dust and water should be evaluated via IP (IEC 60529) or NEMA 250 ratings and chosen to meet your application requirements. Each rating requires testing by a different method, so an enclosure only meeting an underwater IP67 (NEMA 6) rating might not be the right solution for a high- pressure spray down IP66 (NEMA 4) application if both ratings are not stated. Plastic enclosure evaluation should include UV resistance, flammability rating, impact rating, and operational temperature requirements.

Now, let’s talk about Ex. More specifically, Ex eb (increased safety) and Ex tb and tc (protection by enclosure). Depending upon the hazardous area zone of usage, electrical, electronic, and mechanical equipment intended for use in hazardous environments must be independently evaluated for its impact on overall safety. The European Union’s ATEX Directive and the IECEx Certified Product Scheme are two assessment routes used for the safety of equipment in such environments. CONNECTION FLEXIBILITY Selecting a connector with easy integration to the enclosure is essential to overall application success and cost. Choosing a connector that works well with the enclosure makes the production process more efficient, reducing cost. If you have a PCB inside the enclosure, opting for a two-piece connector speeds up manufacturing by using an SMT (surface mount) The Environmental Case System (ECS) from Phoenix Contact protects sensitive electronics in outdoor applications. It has IP67 and IP69 protection and a wide temperature range (-40 to 100°C).


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