Standard Handbook For Electrical Engineers 16th Edition By H Wayne Beaty and Donald G Fink

SI UNITS : 

The units of the quantities most commonly used in electrical engineering (volts, amperes, watts, ohms, etc.) are those of the metric system. They are embodied in the International System of Units (Système International d’Unités, abbreviated SI). The SI units are used throughout this handbook, in accordance with the established practice of electrical engineering publications throughout the world. Other units, notably the cgs (centimeter-gram-second) units, may have been used in citations in the earlier literature. The cgs electrical units are listed in Table 1-9 with conversion factors to the SI units. The SI electrical units are based on the mksa (meter-kilogram-second-ampere) system. They have been adopted by the standardization bodies of the world, including the International Electrotechnical Commission (IEC), the American National Standards Institute (ANSI), and the Standards Board of the Institute of Electrical and Electronics Engineers (IEEE). The United States is the only industrialized nation in the world that does not mandate the use of the SI system. Although the U.S. Congress has the constitutional right to establish measuring units, it has never enforced any system. The metric system (now SI) was legalized by Congress in 1866 and is the only legal measuring system, but other non-SI units are legal as well.

Other English-speaking countries adopted the SI system in the 1960s and 1970s. A few major

industries converted, but many people resisted—some for very irrational reasons, denouncing it as

“un-American.” Progressive businesses and educational institutions urged Congress to mandate SI.

As a result, in the 1988 Omnibus Trade and Competitiveness Act, Congress established SI as the

preferred system for U.S. trade and commerce and urged all federal agencies to adopt it by the end

of 1992 (or as quickly as possible without undue hardship). SI remains voluntary for private U.S.

business. An excellent book, Metric in Minutes (Brownridge, 1994), is a comprehensive resource for

learning and teaching the metric system (SI).