Circuit Protection Knowledge Center
The relentless pursuit of protection for electrical components, systems - and the people who use them.
Company Overview
Ferraz Shawmut is an international company manufacturing the widest range of circuit protection and thermal management solutions in the electrical industry. 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 technical support teams to increase effectiveness, simplify applications, and enhance productivity.
Ferraz Shawmut offers a complete line of current-limiting fuses and accessories and prides itself on delivering innovative, problem-solving products like Amp-Trap 2000® fuses, Surge-Trap® Surge Protective Devices, the Thermally Protected Metal Oxide Varistor (TPMOV®), the SmartSpot® open-fuse indicator, and UltraSafeTM fuse holders.
On the Web
- Ferraz Shawmut Website
- Cross Reference Search
- Catalog Search
- Sales Locator
- Ferraz Shawmut Library
- Articles & White Papers
Resources/Tools
Arc Flash Info Center
Because Ferraz Shawmut has been heavily involved with arc flash testing and research, the company has developed this Web site to provide a reliable source of information about this vital, still-evolving topic.
Arc Flash Calculator
This calculator can be used to determine incident heat energy at a particular distance and the category of PPE required. Simply enter the bolted fault current, choose a current-limiting fuse from the drop-down menu and select "calculate."
Electrical Safety Seminars
Ferraz Shawmut offers several courses to help keep you up to date on the many developments in the electrical industry that are leading to safer workplaces. These courses are taught by veteran experts and are being offered around the country.
Select-A-Fuse Software
The industry's first point-and-click, Windows-based fuse selection software, Select-A-Fuse is fast, easy and accurate. Download your free copy or request the software on CD.
Contact Us
Ferraz Shamut | North America
374 Merrimac Street
978-462-6662
www.us.ferrazshawmut.com
Info@ferrazshawmut.com
White Papers
Reduce System Downtime by Correctly Coordinating Selectivity Between Overcurrent Protective Devices
Selectivity between overcurrent protective devices is desirable and may even be mandatory. Traditional time-current curve analysis may not accurately portray the degree of selectivity existing when current-limiting overcurrent protective devices are involved. It is important for designers to limit the outage to only that circuit which is overloaded or which has faulted in order to avoid shutting down healthy parts of the electrical distribution system. This white paper tech topic will discuss viable methods for evaluating selectivity between current-limiting fuses and non current-limiting circuit breakers.
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Arc Flash Basics: Testing Update
The last 15 years have seen tremendous progress being made in protecting workers against the heat energy associated with arc flash. Research into such injuries in the United States during the 1990's showed that over 2,000 workers were admitted to burn centers each year. One major area of improvement has been the steps taken to get workers into safer clothing.
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Effect of Electrode Orientation in Arc Flash Testing
This paper describes arcing fault tests done in a metal box in a high-power test laboratory. High-speed video and calorimetry were used to study arcing phenomena with vertical and horizontal arrangements, and the results confirmed Stokes and Sweeting's findings that the horizontal case is more severe. When current-limiting fuses were used in their current-limiting range, there was no significant difference between the vertical and horizontal arrangements.
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Improved Method for Arc Flash Hazard Analysis
Conventional arc flash hazard calculators use simple formulae to calculate the flash protection boundary and the incident energy density, but these methods do not represent the effects of the power supply system correctly. A new method models the transient response of a three-phase power system and its interaction with an arcing fault.
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Protection Intelligence Quotient (PIQ) Quiz - New
Proper Selective Coordination can help ensure the smooth operation and reliabilitiy of our plant's electrical distribution system. It does this by limiting electrical interruptions to just the circuit experiencing the problem without shutting down the rest of your facility. Find out how much you know about Selective Coordination by taking this new Quiz.
PIQ Quiz Archive
Ferraz Shawmut makes it easy for you to continue testing your circuit protection knowledge with the company's handy archive of prior quizzes. Topic include Arc Flash Hazard Protection, Solar Power Circuit Protection and Overvoltage Protection.
Tech Topics
Standards & Codes, Note 1: Achieve Higher SCCRs for Industrial Control Panels
Articles 409.110 and 670.3 in the National Electrical Code require industrial control panels to be clearly marked with a Short Circuit Current Rating (SCCR). NEC recognizes UL 508A, the Supplement SB, as an approved method for determining panel SCCR.
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Arc Flash Note 1: Multiple Hazards of Arcing Faults
Based on previous statistics, it's expected that the explosive energy released during arcing faults will send more than 2,000 American workers to burn centers this year. Most of these people will not have been properly warned of the hazards associated with arc flash or adequately trained in how to protect themselves.
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Arc Flash Note 2: Reducing Arc Energies with Current-Limiting Fuses
Current-limiting fuses can reduce the magnitude and duration of a fault current. A UL Listed, current-limiting fuse must clear a short circuit current in less than one-half cycle in its current-limiting range. In this condition, the fuse will melt in the first quarter cycle and prevent the fault current from reaching the first peak of the asymmetrical waveform, significantly limiting the total electrical energy delivered to the fault.
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Arc Flash Note 3: Arc Flash Hazard Analysis
Section 110.8(B)(1) of NFPA 70E requires that an electrical hazard analysis be performed to ensure that workers are properly protected whenever they work on or near equipment that is not in an "electrically safe condition". This includes work required to deenergize equipment.
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Arc Flash Note 4: Reduce Arc Flash Energies by Upgrading to A6D Class RK1 Fuses
Arc flash incident energies can often be reduced by replacing UL Class RK5, Class K and Class H fuses with A6D UL Class RK1 fuses. This is an easy and inexpensive solution; A6D fuses fit into the same fuse holders.
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