IEC 60228 is the
International Electrotechnical Commission
The International Electrotechnical Commission (IEC; in French: ''Commission électrotechnique internationale'') is an international standards organization that prepares and publishes international standards for all electrical, electronic and ...
(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
Overhead power cabling. The conductor consists of seven strands of steel (centre, high tensile strength), surrounded by four outer layers of aluminium (high conductivity). Sample diameter 40 mm
A wire is a flexible strand of metal.
Wire is co ...
in terms of its cross-section area, rather than its
diameter
In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle. Both definitions are also valid fo ...
, because the cross section is directly proportional to its strength and weight, and inversely proportional to its
resistance
Resistance may refer to:
Arts, entertainment, and media Comics
* Either of two similarly named but otherwise unrelated comic book series, both published by Wildstorm:
** ''Resistance'' (comics), based on the video game of the same title
** ''T ...
. 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
* Class 5: Flexible conductor
* Class 6: Very Flexible conductor
Size
The ''nominal'' (see below) cross-sectional area for standard conductors including the following:
* Class 2: Minimum number of strands required to make particular conductor size
* Class 5 and 6: Maximum diameter of any component strand of the conductor
Resistance
The maximum permissible resistance (in ohms per kilometre – Ω/km) of each conductor size, class and type (both plain copper and metal coated)
Purpose of the document
This document and its precursors were created due to a need for a standard definition of cable conductor size. The main problem being that not all copper has the same resistivity value, so, for example, a 4 mm
2 conductor from two different suppliers may have different resistance values. Instead this document describes conductors by their ''nominal'' size, determined by resistance rather than physical dimensions. This is a key distinction as it makes a standardized definition of conductors based solely on their electrical characteristics.
Almost all characteristics of conductors, resistance, current carrying capacity etc. are dependent on the physical dimensions of the conductor. However this document allows an easy reference whereby the standard conductor sizes and reference to physical dimensions are maintained but given an exact meaning in terms of the electrical characteristics of a conductor.
Footnotes
See also
*
*
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. ...
, Unusual unit used as the North American Electrical industry standard for wires larger than 4/0.
*
American wire gauge (AWG), used primarily in the US and Canada
*
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 ...
(SWG), the British imperial standard BS3737, superseded by the metric.
*
Stubs Iron Wire Gauge
*
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 ye ...
*
Body jewelry sizes
*
Electrical wiring
*
Number 8 wire, a term used in the New Zealand vernacular
References
External links
*
#60228
Wire gauges
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