- IEC 60228
IEC 60228 is the
International Electrotechnical Commission 'sinternational standard on "conductors of insulated cables".Among other things, it defines a set of standard wire cross-sections:
In engineering applications, it is often most convenient to describe a
wire in terms of its cross-section area, rather than itsdiameter , 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.
Also Known As
This document is equivalent to:
*CEI 60228
*EN 60228Description
The document describes several aspects of the conductors for electrical cables
Class
This refers to the flexibility of a conductor
*Class 1: Solid conductor
*Class 2: stranded conductor intended for fixed instalation
*Class 5: Flexible conductor
*Class 6: Very Flexible conductorize
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&6: Maximum diameter of any component strand of the conductorResistance
The required maximum resistance (in ohms/km)of each conductor size, class and type (both plain copper and metal coated)
Purpose of the document
History
This document and it's 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 4mm^2 conductor from two different suppliers may have different resistance values. Instead this document describes conductors by their "nominal" size.
Nominal Size
This is the size of a conductor determined by it's resistance rather than it's physical dimensions. This is a key distinction as it makes a standardised definition of conductors based solely on thier electrical characteristics.
Almost all characteristics of conductors, resistance, current carrying capacity etc are independant of the physical dimensions of the conductor. However this document allows an easy refference 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.
ee also
*
American wire gauge
*Imperial Wire Gauge & British Standard Gauge
*
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