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Circular Mil
A circular mil is a unit of area, equal to the area of a circle with a diameter of one mil (one thousandth of an inch or ). It is equal to /4 square mils or approximately . It is a unit intended for referring to the area of a wire with a circular cross section. As the definition of the unit contains , it is easy to calculate area values in circular mils when the diameter in mils is known. The area in circular mils, , of a circle with a diameter of mils, is given by the formula: \_\mathrm = \_\mathrm^2. In Canada and the United States, the Canadian Electrical Code (CEC) and the National Electrical Code (NEC), respectively, use the circular mil to define wire sizes larger than 0000 AWG. In many NEC publications and uses, large wires may be expressed in thousands of circular mils, which is abbreviated in two different ways: kcmil or MCM. For example, one common wire size used in the NEC has a conductor diameter of 0.5 inches, or 500 mils, and thus a cross-section of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Units Of Measurement
A unit of measurement, or unit of measure, is a definite magnitude (mathematics), magnitude of a quantity, defined and adopted by convention or by law, that is used as a standard for measurement of the same kind of quantity. Any other quantity of that kind can be expressed as a multiple of the unit of measurement. For example, a length is a physical quantity. The metre (symbol m) is a unit of length that represents a definite predetermined length. For instance, when referencing "10 metres" (or 10 m), what is actually meant is 10 times the definite predetermined length called "metre". The definition, agreement, and practical use of units of measurement have played a crucial role in human endeavour from early ages up to the present. A multitude of System of measurement, systems of units used to be very common. Now there is a global standard, the International System of Units (SI), the modern form of the metric system. In trade, weights and measures are often a su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NFPA 70
The National Electrical Code (NEC), or NFPA 70, is a regionally adoptable standard for the safe installation of electrical wiring and equipment in the United States. It is part of the National Fire Code series published by the National Fire Protection Association (NFPA), a private trade association. Despite the use of the term "national," it is not a federal law. It is typically adopted by states and municipalities in an effort to standardize their enforcement of safe electrical practices. In some cases, the NEC is amended, altered and may even be rejected in lieu of regional regulations as voted on by local governing bodies. The "authority having jurisdiction" inspects for compliance with the standards. The NEC should not be confused with the National Electrical Safety Code (NESC), published by the Institute of Electrical and Electronics Engineers (IEEE). The NESC is used for electric power and communication utility systems including overhead lines, underground lines, and powe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Wiring
Electrical wiring is an electrical installation of Electrical cable, cabling and associated devices such as switches, distribution boards, sockets, and light fittings in a structure. Wiring is subject to safety standards for design and installation. Allowable wire and electrical cable, cable types and sizes are specified according to the circuit operating voltage and electric current capability, with further restrictions on the environmental conditions, such as ambient temperature range, moisture levels, and exposure to sunlight and chemicals. Associated circuit protection, control, and distribution devices within a building's wiring system are subject to voltage, current, and functional specifications. Wiring safety codes vary by locality, country, or region. The International Electrotechnical Commission (IEC) is attempting to harmonise wiring standards among member countries, but significant variations in design and installation requirements still exist. Wiring methods ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Body Jewelry Sizes
Body jewelry sizes express the thickness of an item of body jewelry, using one of several possible systems. Background Items of body piercing jewelry have an important common factor: the diameter of the part of the item of jewelry where it will rest in the piercing site. With the wearing of European-traditional kinds of earrings, that thickness is not an issue, because jewelry is made to use only thin wire for support, and the wearer need only have a narrow piercing hole to accommodate it. But with body jewelry, there is a wide variety of possible sizes, and wearers generally want jewelry that is the same size as their piercing site. Some wearers want increasingly larger sizes to deliberately stretch the hole. So that wearers can choose the size they want, there are standards for body jewelry sizes, used by jewelry makers and sellers. Generally, the system of gauge-and-inches is used: In gauge notation, jewelry less than ″ thick is ''typically'' measured in a system ori ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jewelry Wire Gauge
Jewelry wire is wire, usually copper, brass, nickel, aluminium, silver, or gold, used in jewelry making. Wire is defined today as a single, usually cylindrical, elongated strand of drawn metal. However, when wire was first invented over 2,000 years BC, it was made from gold nuggets pounded into flat sheets, which were then cut into strips. The strips were twisted and then rolled into the round shape we call wire. This early wire, which was used in making jewelry, can be distinguished from modern wire by the spiral line along the wire created by the edges of the sheet. Modern wire is manufactured in a different process that was discovered in Ancient Rome. In this process, a solid metal cylinder is pulled through a draw plate with holes of a defined size. Thinner sizes of wire are made by pulling wire through successively smaller holes in the draw plate until the desired size is reached. When wire was first invented, its use was limited to making jewelry. Today, wire is used e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stubs Iron Wire Gauge
The Birmingham gauge, officially the Birmingham Wire Gauge and often abbreviated as ''G'' or ''ga'', is unit or wire gauge used to measure the thickness or diameter of wires and tubing, including hypodermic needles and other medical tube products. Terminology The Birmingham gauge is also known as the Stubs Iron Wire Gauge or Birmingham Wire Gauge and is distinct from the Stubs Steel Wire Gauge and the British standard gauge, British Standard Wire Gauge. It is commonly referred to simply as ''gauge'' (abbreviated as ''G''), but this should not be confused with the French gauge, a separate system used for measuring the outer diameter of Catheter, catheters. System The Birmingham gauge ranges from 5/0 or 00000, the lowest gauge number corresponding to the largest size of , to 36, the highest gauge number corresponding to the smallest size of . The increments between gauge sizes are not linear and vary. At higher gauge numbers, the increment between the two highest gauges is , whil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standard Wire Gauge
The British Standard Wire Gauge, often referred to as the Standard Wire Gauge or simply SWG, is a unit used to denote wire gauge (size) as defined by British standard, BS 3737:1964, a standard that has since been withdrawn. It is also known as the Imperial Wire Gauge or British Standard Gauge. Although its use has significantly declined, SWG sizes are still used for measuring the thickness of guitar strings and certain types of electrical wire. In modern applications, wire size is more commonly measured in terms of cross-sectional area, expressed in square millimeters, particularly for electrical installation cables. The current British Standard for metallic materials, including wires and sheets, is BS 6722:1986, which exclusively uses metric measurements. History SWG was fixed by Order of Council August 23, 1883. It was constructed by improving the Birmingham Wire Gauge. It was made a legal standard on 1 March, 1884, by the British Board of Trade. SWG is not to be confused ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IEC 60228
IEC 60228 is the International Electrotechnical Commission (IEC)'s international standard on ''conductors of insulated cables''. the current version is Third Edition 2004-11 Among other things, it defines a set of standard wire cross-sectional areas: In engineering applications, it is often most convenient to describe a wire in terms of its cross-section area, rather than its diameter, because the cross section is directly proportional to its strength and weight, and inversely proportional to its Electrical resistance, resistance. The cross-sectional area is also related to the maximum current (electricity), current that a metallic wire can carry safely. This document is one considered ''fundamental'' in that it does not contain reference to any other standard. Description The document describes several aspects of the conductors for electrical cables Class This refers to the flexibility and thermal effects i.e temperature of a conductor. * Class 1: Solid conductor * Class ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Square Mil
A square mil is a unit of area, equal to the area of a square with sides of length one mil. A mil is one thousandth of an international inch. This unit of area is usually used in specifying the area of the cross section of a wire or cable. Equivalence to other units of area 1 square mil is equal to: * 1 millionth of a square inch (1 square inch is equal to 1 million square mils) * * about 1.273 circular mils (1 circular mil is equal to about 0.7854 square mils). and See also * Circular mil * Area of a circle In geometry, the area enclosed by a circle of radius is . Here, the Greek letter represents the constant ratio of the circumference of any circle to its diameter, approximately equal to 3.14159. One method of deriving this formula, which ori ... References {{DEFAULTSORT:Square Mil Units of area Decimalisation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thou (length)
A thousandth of an inch is a derived unit of length in a system of units using inches. Equal to of an inch, a thousandth is commonly called a thou (used for both singular and plural) or, particularly in North America, a mil (plural mils). The words are shortened forms of the English and Latin words for "thousand" ( in Latin). In international engineering contexts, confusion can arise because ''mil'' is a formal unit name in North America but ''mil'' or ''mill'' is also a common colloquial clipped form of millimetre. The units are considerably different: a millimetre is approximately 39 mils. Contexts of use The thou, or mil, is most commonly used in engineering and manufacturing in non-metric countries. For example, in specifying: * The thickness of items such as paper, film, foil, wires, paint coatings, latex gloves, plastic sheeting, and fibers ** For example, most plastic ID cards are about in thickness. ** Card stock thickness in the United States, where mils are also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overcurrent Protection
Power system protection is a set of techniques and power grid equipment used to limit the damage caused by an electrical fault and safeguard other components of the grid, like Electric generator, generators and power transmission line, transmission lines. The term is also used for a branch of electrical power engineering that deals with the protection. There is an overlap between the power system protection and power system operations, as the protection equipment, like other switchgear, can be used for operations. The protection devices are used to protect the power systems from faults by detecting the faults and taking ''action'' ("tripping"). P. M. Anderson distinguishes the ''reactionary devices'', like protective relays, that "clear" a fault by isolating it from the rest of system and ''safeguard devices'' that address the source of the hazard (for example, an emergency core cooling system of a nuclear reactor). As a discipline, power system protection mostly deals with the r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Fire Protection Association
The National Fire Protection Association (NFPA) is a U.S.-based international nonprofit organization devoted to eliminating death, injury, property damage, and economic loss due to fire, electrical, and related hazards. , the NFPA claims to have 50,000 members and 9,000 volunteers working with the organization through its 250 technical committees. History In 1895, a Committee on Automatic Sprinkler Protection was formed in Massachusetts by men affiliated with several fire insurance companies and a pipe manufacturer to develop a uniform standard for the design and installation of fire sprinkler systems. At the time, there were nine such standards in effect within of Boston, Massachusetts, and such diversity was causing great difficulties for plumbers working in the New England New England is a region consisting of six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New Y ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
