Class AA—For bare conductors usually used in overhead lines.

Class A—For conductors to be covered with weatherresistant (weather-proof), slow-burning materials, and for bare conductors where greater flexibility than is afforded by Class AA is required.

Class B—For conductors to be insulated with various materials such as rubber, paper, varnished cloth, and so forth, and for the conductors indicated under Class A where greater flexibility is required.

Class C and Class D—For conductors where greater flexibility is required than is provided by Class B conductors.

另外: Class G—Conductors consisting of 7 to 61 rope-laystranded
members, each of which consists of 7 to 19
concentric-stranded wires, with total conductor sizes ranging
from No. 14 AWG (2.08 mm2) to 5 000 000 cmil (2534 mm 2).
(Typical use is for rubber-sheathed conductor, apparatus conductor,
portable conductor, and similar applications.)

Class H—Conductors consisting of 19 to 91 rope-laystranded
members, each of which consists of 7 to 19
concentric-stranded wires, with total conductor sizes ranging
from No. 9 AWG (6.63 mm2) to 5 000 000 cmil (2534 mm 2).
Class K construction produces a conductor with greater flexibility
than class G. (Typical use is for rubber-sheathed cord
and applications where flexibility is required such as on
take-up reels over sheaves and extra-flexible apparatus conductor.)

Class I—Conductors consisting of wires 0.0201 in.
(0.511 mm) diameter (No. 24 AWG) to produce rope-laystranded
conductors up to 2 000 000 cmil (1013 mm2) in total
cross-sectional area. (Typical use is for special apparatus
conductor.)

Class K—Conductors consisting of wires 0.0100 in.
(0.254 mm) diameter (No. 30 AWG) to produce rope-laystranded
conductors up to 1 000 000 cmil (507 mm2) in total
cross-sectional area. (Typical use is for special portable cord
and conductors.)

Class M—Conductors consisting of wires 0.0063 in.
(0.160 mm) diameter (No. 34 AWG) to produce rope-laystranded
conductors up to 1 000 000 cmil (507 mm2) in total
cross-sectional area. (Typical use is for welding conductors.)

Class A, B, C, D的要求在ASTM B8里面;
Class G, H的要求在ASTM B173里面;
Class I, K, M的要求在ASTM B 172里面.

欢迎大家学习和交流.

学习了！

刚好用到，非常好的资料~