Published In October 2001
The fuse has been with us almost as long as the controlled use of electricity has—protecting people and equipment against the dangers of short circuits and overloads for more than 100 years. Today, fuses can be responsible for protecting millions of dollars worth of equipment—not to mention protecting personnel from injury and the company from financial loss. Although the basic design and function of fuses are simple, they have evolved to meet the circuit protection demands of today’s complex, sophisticated systems. In spite of this increased system complexity, fuse manufacturers have kept their product simple and effective, while making it easier to use. Low-voltage industrial indicator fuses The idea of being able to readily see when a fuse has opened and needs replacing is not new. Glass, and more recently clear plastic, fuses have been available for very low-voltage applications for many years. Recently, manufacturers have applied that idea to the industrial fuse market. Early offerings of indicator fuses have been in the Class J, Class RK5, and Class RK1 categories, which provide excellent protection, opening in less than one-quarter cycle under short circuit conditions, while providing time delay to minimize nuisance fuse opening. With indicator fuses, maintenance personnel can identify an open fuse at a glance and quickly replace it. This can significantly cut operational downtime, which directly impacts production schedules and costs. So, it’s not surprising that the indicator feature has proven very popular for industrial application and will be added to more classes of fuses in the future. Choices in indicator fuses Some visual indicator fuses have a view-port in the fuse body that turns brown or black when the internal element burns. Pin-type, pop-up indicator fuses are also available. Some fuse holders are even designed with an optional light indicator that signals an open fuse. Safer fuseholders First and foremost, fuses are safety devices—providing electrical protection to both personnel and equipment. But working near possibly live parts has always posed risk to even qualified personnel. One of the most recent improvements in fuse safety was the development of “finger safe” devices that minimize exposure to live parts. Fuse manufactures now offer “finger safe” fuse holders for many common types of fuses, allowing an individual to change fuses with minimal or no exposure to live parts, and without special tools. Help with fuseholders Dedicated fuse selection software, often available free via the Internet, can help determine the fuses needed for a particular application. Fuse manufacturers have adapted the digital medium to their business and offer software programs, which can be downloaded, to make fuse selection and substitution cross-referencing a painless procedure. Trends in fuses Clearly, the globalization of manufacturing and the resulting harmonization of all the various electrical standards of the worldwide market will propel circuit protection manufacturers to develop products that can be applied more universally. In addition, the continued growth of Internet business transactions will allow contractors and distributors to access near-real-time information product availability. Distributors will be able to order directly from manufacturers’ inventories—speeding response time to specific end user requirements. Electrical systems will continue to grow more complex, and fuse manufacturers will continue to develop new products that employ the latest technologies and materials to maintain, and even improve, their margin of safety and cost savings. HOWELL is product communications manager at Ferraz Shawmut, Inc. He can be reached at email@example.com.