Technical Paper Earns 2009 I&CPS Ralph H. Lee Department Prize Paper Award
Newburyport, MA - A technical white paper entitled, "Selectivity Analysis in Low Voltage Power Distribution Systems with Fuses and Circuit Breakers" recently received the 2009 I&CPS Ralph H. Lee Department Prize Paper Award. The award was presented at the 2010 I&CPS Technical Conference Awards luncheon in Jacksonville, FL, USA. The paper was co-authored by Marcelo Valdes, PE and Tom Papallo of GE Consumer & Industrial and Cindy Cline and Steve Hansen of Mersen (formerly Ferraz Shawmut). The paper explores various methods of selectivity in systems using fuses and circuit breakers together, with either device on the line side.
Abstract - Interest in complete overcurrent device selectivity has increased due to the addition of selectivity requirements to articles 700, 701, and 708 of the National Electrical Code (NFPA70). Many users, both commercial and industrial, use fuses and circuit breakers simultaneously. Traditional Time-Current Curve (TCC) analysis is known to not fully communicate fuse selectivity; hence fuse manufacturers publish device ratio guidelines for selection of fuse type and sizes. Recent publications of selectivity tables by circuit manufacturers also demonstrate that traditional TCCs are often insufficient to fully communicate circuit breaker selectivity. Traditional TCCs can lead to incorrect conclusions regarding circuit breaker fuse selectivity, indicating more or less selectivity than may be possible. The authors will describe various methods for assessment of selectivity in systems using both fuses and circuit breakers together, with either device on the line side. The methods will demonstrate that selectivity above what TCCs demonstrate may be possible if devices are selected correctly, and that traditional TCC analysis, can also incorrectly demonstrate more selectivity than a more thorough analysis would predict. The methods lend themselves to analysis that a power system engineer can perform with published information or information that may be requested from manufacturers.
About Mersen
Mersen, formerly Ferraz Shawmut, is worldwide expert in high-performance materials for extreme environments and in the reliability and safety of electrical installations. Drawing on a century of experience-and an ongoing commitment to critical research in electrical safety- it provides industrial, commercial, and OEM customers with innovative products and unsurpassed technical support. The electrical and circuit protection division provides a comprehensive line of current-limiting fuses (low voltage, general purpose, medium voltage, semiconductor, miniature and glass, and special purpose) and accessories, fuse blocks and holders, power distribution blocks, low voltage disconnect switches, surge protection, high power switches, heatsinks, thermal management and more. Amp-Trap® High-Speed Class J (HSJ) fuses, TPMOV® Technology, and the SmartSpot® open-fuse indicator are a few of the company's latest innovations.
Mersen (formerly Ferraz Shawmut)
374 Merrimac Street
Newburyport, MA 01950
