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Artículos técnicos

Actualización del foro sobre arco eléctrico

Etiqueta AF en el desconectador de servicio y el ATS en el mismo gabinete

19 de enero de 2017

With the awareness of arc flash, many giant manufacturers do not manufacture the Service Disconnect and the Automatic Transfer Switch located in the same section or enclosure. However, this practice can be seen in the field for switchboards rated as high as 600 Amps. The dangerous part is the upstream of service disconnect is like a blind spot as the only protective device is the utility’s fuse on the primary side of the transformer and often result in high incident

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IEEE 1584.1-2013

18 de enero de 2017

Question: Hello, good afternoon. Does the standard contain new information to consider for arc flash analysis? Thank you   Answer: No because we’re still on the 2002 edition. The new edition won’t get released until probably next year at the earliest. As to answering your question, sort of yes and no. Three areas I know will change somewhat: 1. The “lower cutoff” (the old 125 kVA comment/rule) will likely change, probably downward in terms of what is “covered” under this

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Responsabilidad y acciones legales

17 de enero de 2017

It’s no secret that the United States is a very litigious country. Sometimes the more “interesting” interpretations that people use regarding codes, standards, design etc. tend to be more influenced by fear of lawsuits. I have had this conversation with many people over the years. There are many reasons that legal action may be taken but this week’s question is very specific. It refers to: Liability from accident, injury, death, equipment failure. It applies to both the Plaintiff and Defendant.

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Evaluación de la energía de inicio de quemaduras de segundo grado en arco eléctrico

21 de diciembre de 2016

Our interest in determining accurate onset to second degree burn energy and its significance in computing the arc flash boundary is focused on the prevention of injury to the skin of a human who might be exposed to an arc-flash. During the last two decades different formulas have been proposed to calculate incident energy at an assumed working distance, and the arc flash boundary in order to determine arc rated personal protective equipment for Qualified Electrical Workers. Among others, the

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¿Incluir fecha en la etiqueta de arco eléctrico?

20 de diciembre de 2016

According to the 2015 Edition of NFPA 70E 130.5(2), The arc flash risk assessment “…shall be reviewed periodically, at intervals not to exceed 5 years, to account for changes in the electrical distribution system that could affect the results of the arc flash risk assessment.” According to 130.5(D) Equipment Labeling, the date is not listed as a requirement for including on the label. However, many believe the date is an important aspect of the label in order to keep track

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Método de recogida ajustado – Factor de cambio

19 de diciembre de 2016

I have been looking into the adjusted pickup method and associated shift factors used when multiple source bus configurations are being coordinated [ex. parallel generator systems two or more] and was hoping someone could point me to an IEEE standard or some industry articles on this to better understand this on shifting TCC’s around a specific location or device. On one example where two different sized generators were modeled it shifted the smaller units beyond the TCC of the larger

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Ropa que no se derrite

16 de diciembre de 2016

Our company in the past 2 years has implemented an electrical safety and control of hazardous energy program for employees world-wide. Our daily work-wear clothing minimum requirement is non-melting clothing, except in US and Canada for which our AFHA’s determine minimum PPE requirements. Unfortunately, many countries have yet to recognize arc flash is a real threat to people and arc flash isn’t isolated to just North America. (Good news is they are beginning to wake up!) As the implementation project

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Comportamiento de los tejidos de indumentaria durante el calentamiento convectivo y radiante

14 de diciembre de 2016

Personal protective equipment (PPE) recommended for arc flash is not always designed for arc flash exposure. The purpose of this paper is to warn of the dangers posed by using the improper materials in arc flash exposures until standards have caught up on this issue. The table below shows a representative range of everyday textiles along with some of the measurements of importance in establishing their response towards convective and radiant heating[1]:   Times to ignition or melting of the

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Retorno seguro al servicio después de una interrupción de mantenimiento

12 de diciembre de 2016

Best Practices for a Safe Return-to-Service Following a Maintenance Outage Charles M. McClung, MarTek Limited Russell R. Safreed, PE, MarTek Limited Abstract Returning electrical equipment to service after a planned maintenance outage creates a unique set of hazards. Facility managers are under stringent time constraints for taking the system out of service, performing necessary maintenance tasks (as well as making un-anticipated repairs) and returning the system to service by the appointed time. These common, real-world factors may create circumstances that

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Cambios en la norma NFPA 70E de 2015

9 de diciembre de 2016

The following is an article that I wrote a few years ago listing the major changes for the 2015 edition. It was originally published in the May 2014 issue of Electrical Contractor Magazine and is provided here as a resource for your use. Change Is On The Way! 2015 NFPA 70E Published: May 2014 – Electrical Contractor Magazine By Jim Phillips Deja vu? Déjà vu is that feeling you get when you think you have seen or done something before. NFPA

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