Engineering Design The Aluminum Association（工程设计铝业协会）.pdf

Section II Bare Aluminum Wire and Cable Chapter 3 Engineering Design This chapter describes lbe principal design features of AWG numbered sizes represent the approximate reduction bare uninsulated conductors; however much lbat applies in diameter associated with each successive step of wire to hare conductors also pertains to lbe metaUic part of in­ drawing. sulated or covered conductors which are considered in Fig. 3-1 shows typical full-size cross-sections, and Section III. approximate relationships between the sizes. Many types of bare conductors are in use depending on For wire sizes larger than 4/0 AWG, the size is desig­ application requirements. They may differ in electrical and nated in circular mils. Wire sizes of 4/0 AWG and physical properties, configuration, method of assembly, smaller also are often designated in cir mils. One cir mil and corrosion resistance. Certain general physical prop­ is the area of a circle I mil (0.001 in.) diameter; that is, the erties have been described in previous chapters. Detailed area in cir mils equals diameter-in-mils squared. physical and electrical properties of lbe various com­ mercial sizes of bare conductors are listed in Chapter 4. As one emil = ./4 sqmils (Eq.3-1) Area in cir mils 1.2732X 10 X area in sq. in. For many years it has been the practice to employ code Expressing diameter of wire D, in inches words to identify and precisely define specific conductor D = 1O