Electronics Protection - Winter 2014 - (Page 14)

Feature Seven Essential Cabinet Design Considerations for Protecting 19-Inch Electronics Vlad Konopelko, Product Marketing Manager, North America, Pentair's Schroff Brand The latest advancements in electro-mechanical technologies, coupled with stringent compliance and compatibility requirements, allow for the development and deployment of high-performance electronics beyond traditional 19 inch Data-Communications and Telecommunications applications. Accordingly, depending on the application, it is important to utilize 19 inch cabinets that are designed for effective and robust protection of sensitive electronics in non-communications environments-such as extreme heat, high dust/contaminants, clean room/laboratories, Radio-Frequency/Electromagnetic interference (RFI/EMI) and high shock and vibration. This article introduces seven mechanical structure and protection standards design considerations for specifying a reliable 19 inch electronics cabinet solution. One - Design Standards Design standards are defined and developed by standards committees, government agencies, and regulators. Standards result from technical agreements related to design specifications and requirements that need to be fulfilled by a product or service. They are widely recognized at the domestic and international level, and are widely adopted by engineers, manufacturers, trade organizations, testing laboratory and other vested parties. Some key design standards associated with electronics cabinets include the following: IEC & NEMA - International Electrotechnical Commission (IEC) develops International standards for all electrical, electronic and related technologies. Adoption is voluntary, although they are often referenced in national laws or regulations around the world. Experts from around the world collaborate and develop IEC International Standards. IEC 60297 (Mechanical structures for electronic equipment - Dimensions of mechanical structures of the 482,6 mm (19 in) series) standard provides crucial information for designing 19 inch cabinets - IEC 60297 IEC 60297-3-100 (19 inch Standard); IEC 60917-2-2 (25mm metric Standard); ETS 300 119-2/-3 (European Telecommunication Standard) NEMA is the association of electrical equipment and medical imaging manufacturers. NEMA includes more than 400 member companies and provides a forum for developing technical design and safety standards that are in the best interests of the industry. Each standards organization includes member companies from diverse industries that manufacture products used in the generation, transmission, distribution and utilization of electricity. Some examples include industrial, test & measurement, medical imaging, energy, transportation and communications. 14 Winter 2014 * www.ElectronicsProtectionMagazine.com Network Equipment-Building System (NEBS) - NEBS is not a regulatory requirement, but more of a best-practices standard that became widely referenced in the telecom industry. Telcordia (now part of Ericsson) manages specifications and provides a series of General Requirements (GR) for communications electronic and mechanical solutions - key cabinet requirements include NEBS GR63-CORE (physical protection, such as thermal load calculation and seismic Zone 4) and GR-1089-CORE (electromagnetic compatibility and electrical safety. UL Standard - UL (Underwriters Laboratory) is a global independent safety consulting and certification company that focuses on ensuring electrical safety standards. More information may be found on the UL website. RoHS Compliance Restriction of Hazardous Substances (RoHS), originated in the European Union and restricts the use of six hazardous materials found in electrical and electronic products. MIL-S-901D - is a special military test requirement designed for shipboard applications. Based on the type of equipment, essential or non-essential to the safety and combat-readiness of the ship, qualification testing is performed on a specified machine placed on a barge floating in a pond where explosive charges are detonated at various distances and depths to impart shock upon the equipment. Two - Cabinet Dimensions Nineteen inch cabinets provide a standardized frame or enclosure for mounting various types of electronics equipment. Each piece of equipment is typically 19 inches (482.6 mm) wide, including edges or mounting ears, which allow for mounting to the rack frame. Cabinet height is defined in Units (U), each unit equals an industry standard of 1.75 inches (44.45 mm). Rack-mountable equipment is usually designed to occupy a specified number of U. For example, a piece of test equipment may be 4U high, most rack-mountable computers are between 1U and 5U and some high-availability computing solutions may need as much as 13U. Cabinet depths may vary in accordance with diverse applications, typical depths range 600 to 1,200 mm. Detailed guidance regarding mechanical structure standards for 19-inch electronics may be referenced in IEC 60297-3-100. Three - Weight Load Capacity The amount of weight loaded into a cabinet can vary widely, so it's important to take a look at this factor to determine the right type of cabinet for a given application. Whether it is several banks of batteries for uninterruptible power supplies, or an array of hard drives, proprietary equipment or other heavy components, under- http://www.ElectronicsProtectionMagazine.com

Table of Contents for the Digital Edition of Electronics Protection - Winter 2014

Editor's Choice
EMI Compliance: Choosing the Right Shielding and Gasketing
Thermal-Fluid Modeling for Flat Thin Heat Pipes/Vapor Chambers
Increase Rack Cooling Efficiency and Solve Heat-Related Problems
Seven Essential Cabinet Design Considerations for Protecting 19 Inch Electronics
A Better Alternative to Heat Pipes: Integrating Vapor Chambers Into Heat Sinks
Common IP Testing Failures and How to Avoid Them
Enclosures
EMI/EMC/RFI
Thermal
Power
Hardware
Contamination
Industry News

Electronics Protection - Winter 2014