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Effective Selective Coordination Set-ups - Pt. 2Author: Chris B Posted Date: 3/12/2010 7:49:38 AM
As I mentioned in my last entry about SC, there are a couple of methods that are most common for figuring out proper selective coordination. With any of these, the results should be interpreted correctly by a qualified individual.
1. Short-circuit current calculation study: This method is appropriate if circuit breakers are being used. It involves plotting time-current characteristic curves and then interpreting that data properly. An engineer can look at this information and determine whether or not selective coordination has been achieved.
2. Adhering to selectivity ratios: You'll go this route if fuses are being used. Just use fuse types and ampere ratings that adhere to the particular manufacturer's selectivity ratios. This is the easier method of the two.
Cooper Bussmann, however, makes it even easier to design and install systems with proper selective coordination. They publish Fuse Selectivity Ratio Tables for people to refer to. All that's required is that you make sure all fuse types and ampere rating ratios for the mains, feeders and branch circuits meet or exceed these listed selectivity ratios. You then can leave fuses where they are or adjust things accordingly. There's nothing else to analyze, and no other settings to tweak with!
If you'd like to get an even better grasp on Bussmann's method for meeting SC, you can read more detailed information here:
Comments (0) | Leave Comments |  Permalink cooper bussmann, fuses, circuit breakers, selective corrdination, calculation, selectivity ratios, electrical distribution, quality, power, blackouts, faults, nec 2008
Fuses and NEC 2008 ChangesAuthor: Chris B Posted Date: 3/9/2010 5:09:56 PM
Recent catastrophic events like hurricane Katrina and 9/11 have made a lot of people take notice, especially those behind the National Electric Code. As part of a huge shift in focus toward life safety (like new AFCI/GFCI and tamper-resistant receptacle requirements), there have been a number of changes in regard to power devices. The events I mention above were monumental in drawing attention to the need for system load reliability. Whenever part of a building is damaged or failing, a key objective is clearly maintaining power to the "vitals" as long as possible.
This is where "selective coordination" comes into play. Selective coordination is the act of isolating a faulted circuit from the rest of an electrical system, which is the best way to eliminate unnecessary power outages. You do this by using overcurrent protective devices that have ratings and settings just like a particular overcurrent condition.
For your own reference, here's a quick list of applications where selective coordination is required per the NEC:
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Healthcare facilities, which have essential electrical systems like critical branches and life safety branches. (Article 517.26)
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Certain types of elevators (Article 620.62)
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Emergency systems in places where people frequently assemble, such as hotels, theaters, sports arenas, health care facilities, etc. (Article 700.27)
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Legally required standby systems, like those that serve loads in heating and refrigeration, smoke systems, communication systems, ventilation systems, sewage disposal, and other processes where any interruption would be hazardous. (Article 701.18)
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Critical Operations Power Systems with loads for communication and data centers. (Article 708.54)
I'll pick up next time with more detail on what selective coordination is, and what compliance means in light of NEC. Comments (1) | Leave Comments | Permalink bussmann, fuses, selective coordination, applications, nec 2008, national electric code, power, safety
Upcoming Series on "Selective Coordination"Author: Chris B Posted Date: 3/8/2010 5:25:58 PM
What is selective coordination? What do these mean anyway for electrical devices? Does this affect you in any tangible way?
To answer these questions - and certainly a slew of others - I'm starting a series of posts on the latest National Electric Code (NEC) requirements in relation to fuses.
You can look forward to a number of posts over the next few weeks covering all this. Comments (0) | Leave Comments | Permalink bussmann, fuses, selective coordination, support, nec, 2008, electrical
Bussmann's Low-Peak Fuse AdvantageAuthor: Chris B Posted Date: 5/15/2009 5:51:01 PM
There's always been a concern in the electrical industry over safety and reliability of devices in high-energy environments. Just look at the injuries caused by arc faults, which can and will happen in a fraction of a second:
- Deep burns and even death to workers because of clothing catching fire.*
- Seriously broken bones like fractured ribs, collapsed lungs, and any other conceivable injury that would be caused by being hurled a great distance.*
- These blasts are also known to hurl equipment shrapnel at ridiculously high velocities (we're talking in excess of around 700 m.p.h.).*
This is serious stuff. But as we've come to understand the dangers better over the years, companies like Cooper Bussman have also come up with great solutions. As opposed to simple circuit breakers, for example, Bussmann's Low-Peak fuses are specifically made to provide more efficient downtime reduction, improved workplace safety, and exceptionable code compliance.  Two of the best Low-Peak features, in my opinion, are current-limits on the fuses (which cut down substantially on the risk of arc-flashes) and easyID fuse indication technology (which tells you in black-and-white exactly when a fuse needs replacing).
Low-Peak fuses are a smart move if you want to correct these common workplace problems. I can't stress enough how important it is to make electrical work simple and hazard-free for your personnel.
Comments (0) | Leave Comments | Permalink bussmann, fuses, low-peak, safety, hazards, arc faults, industrial, workplace
OneStopBuy.com Now Carrying Bussman FusesAuthor: Chris B Posted Date: 5/13/2009 8:04:54 PM
FOR IMMEDIATE RELEASE
OneStopBuy.com Now Carrying Bussmann Fuses
Independence, KS – May 14, 2009 -- OneStopBuy.com, Inc. today announced that they have begun offering complete access to over 6,000 Cooper Bussmann fuses. With a more than 90-year history, Cooper Bussmann remains one of the finest manufacturers of North American and European-styled fuses for the electrical, electronics and transportation industries, plus inductors and transformers for power quality in electronic applications.
As an authorized Bussmann distributor, OneStopBuy offers Toll-Free and Live Chat access to qualified technical and customer support assistants who can answer any questions you have about fuse products. OneStopBuy also provides fast, economical shipping as well as expedited shipping options.
ABOUT ONESTOPBUY.COM, INC.
OneStopBuy.com is a fast growing online electrical distributor who provides all consumers with unrestricted access to the entire product offering of the manufacturers they represent.
Currently OneStopBuy.com represents:
- Cooper Bussmann - Complete access to the finest offering of Electrical and Electronic fuses
- Leviton Manufacturing – offering 10,000 wiring devices and telecommunications products
- HD-Products – offering the innovative flat screen TV installation solution “PowerBridge”
- Omni Cable – access to over 3,000 different types of wire and cable, many by the foot
All of these manufacturers’ product lines are organized under OneStopBuy’s On-Line Catalog which is both intuitive and easy to use. OneStopBuy.com focuses on providing their customers simple selection of products, unparalleled technical support, and efficient handling of orders at competitive prices.
CONTACT:
Chris Bacavis
chrisb@onestopbuy.com
401 N 2nd Street
Independence, KS 67301
Ph: 1-877-633-5212
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9/6/2010 7:29:24 PM
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