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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 corresponds to 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 knowing the diameter in mils. The area in circular mils, , of a circle with a diameter of mils, is given by the formula: :A = d^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 cross-section of 250,000 circular mils, written as 250 kcmil or 250 MCM, which is the first size larger than ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Units Of Measurement
A unit of measurement 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 is often a subject of governmental r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Fire Protection Association
The National Fire Protection Association (NFPA) is an international nonprofit organization devoted to eliminating death, injury, property and economic loss due to fire, electrical and related hazards. As of 2018, 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 region. The next year, the committee published its initial report on a uniform standard, and went on to form the NFPA in late 1896. The committee's initial report evolved into NFPA 13, ''Standard for the Installat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Wiring
Electrical wiring is an electrical installation of 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 codes of practice and regulat ... [...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 origina ... [...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 is a wire gauge system, and is also used to specify thickness or diameter of hypodermic needles and tube products. Terminology Birmingham gauge is also known as the Stubs Iron Wire Gauge or Birmingham Wire Gauge. It is not the same as, though similar to, the Stubs Steel Wire Gauge. Birmingham gauge is often simply termed Gauge, with the abbreviation G. However, this should not be confused with French gauge. System The gauge starts at the lowest gauge number of 5Ø or 00000, corresponding to the largest size of , and runs to the highest gauge number of 36, corresponding to the smallest size of . Size steps between gauges range from between high gauge numbers to between the two lowest gauge numbers and do not correspond to a particular mathematical pattern, although for the most part the steps get smaller with increasing gauge number. Concerning wire and fine tubing, the gauge number is used to specify the outside diameter of the product, whereas for larg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standard Wire Gauge
British Standard Wire Gauge (often abbreviated to Standard Wire Gauge or SWG) is a unit for denoting wire size given by BS 3737:1964 (now withdrawn). It is also known as the Imperial Wire Gauge or British Standard Gauge. Use of SWG sizes has fallen greatly in popularity, but they are still used as a measure of thickness in guitar strings and some electrical wire. Cross sectional area in square millimetres is now the more usual size measurement for wires used in electrical installation cables. The current British Standard for metallic materials such as wire and sheet is BS 6722:1986, which is a solely metric standard. 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 with American wire gauge, which has a similar but not interchangeable numbering scheme. Standard A table of the gauge numbers and wi ... [...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 resistance. The cross-sectional area is also related to the maximum current that a 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 2: Stranded conductor intended for fixed installation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gauge Chart
Gauge ( or ) may refer to: Measurement * Gauge (instrument), any of a variety of measuring instruments * Gauge (firearms) * Wire gauge, a measure of the size of a wire ** American wire gauge, a common measure of nonferrous wire diameter, especially electrical ** Birmingham gauge, a measure of ferrous wire and hypodermic needle diameter ** Jewelry wire gauge, the size of wire used in jewelry making * Sheet metal gauge, thickness of metal in sheet form * Film gauge, a physical property of film stock which defines its size * The size of objects used in stretching (body piercing), especially earrings * Gauge block, a metal or ceramic block of precisely known dimension, used in measuring * Sight glass, also known as a water gauge, for measuring liquid level heights in storage tanks and pressure vessels * Boost gauge, a gauge used in conjunction with turbo-super-chargers * Pressure gauge or vacuum gauge, see pressure measurement * Gauge pressure, pressure above ambient pressure * ... [...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) * 6.4516×10−10 square metres * about 1.273 circular mils (1 circular mil is equal to about 0.7854 square mils). Where 1.273 is (1÷(π÷4)) and where 0.7854 is (π÷4). 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 origi ... {{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 branch of electrical power engineering that deals with the protection of electrical power systems from faults through the disconnection of faulted parts from the rest of the electrical network. The objective of a protection scheme is to keep the power system stable by isolating only the components that are under fault, whilst leaving as much of the network as possible in operation. The devices that are used to protect the power systems from faults are called protection devices. Components Protection systems usually comprise five components *Current and voltage transformers to step down the high voltages and currents of the electrical power system to convenient levels for the relays to deal with *Protective relays to sense the fault and initiate a trip, or disconnection, order *Circuit breakers or RCDs to open/close the system based on relay and autorecloser commands * Batteries to provide power in case of power disconnection in the system *Communic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
