UL 66:2018-06 Fixture Wire.
These types are for use as specified in Article 402 and other applicable parts of the National Electrical Code (NEC), ANSI / NFPA 70. These types are as described individually in index Tables 4.1 — 4.9 of this standard.
2 Units of Measurement
2.1 In addition to being stated in inch/pound units, each numerical requirement in this standard is also stated in units that make the requirement conveniently usable in the various metric systems (practical SI and customary). Equivalent — although not necessarily exactly identical — results are to be expected from applying a requirement in inch/pound or metric terms. Equipment calibrated in metric units is to be used when a requirement is applied in metric terms.
3.1 Whenever the designation “UL 1581” is used in this wire standard, reference is to be made to the
designated part(s) of the Reference Standard for Electrical Wires, Cables, and Flexible Cords, UL 1581.
4 Index Tables
4.1 Tables 4.1 — 4.8 each serve as an index to the requirements for construction details, test performance, and marking of the wire types described in the particular table. Each vertical column summarizes and references the requirements that apply to the particular wire whose type letters appear at the top of the column. The applicable paragraphs and tables in this standard (UL 66) are indicated in parenthesis. Square brackets […] indicate the applicable parts of UL 1581.
5.1 Each material used in a fixture wire shall be applicable for the use and shall be compatible with all of the other materials used in the wire.
6.1.1 Except as noted in 6.1.2, all conductors shall be of soft-annealed copper complying with the American Society for Testing and Materials Standard Specification for Soft or Annealed Copper Wire, ASTM B 3-01. Copper strands that are smaller in diameter than 0.015 inch or 0.38 mm and are uncoated or have a coating of tin complying with the Standard Specification for Tinned Soft or Annealed Copper Wire for Electrical Purposes, ASTM B 33-00, or a tin/lead alloy coating complying with the Standard Specification for Lead-Coated and Lead-Alloy-Coated Soft Copper Wire for Electrical Purposes, ASTM B 189-95, are for products whose temperature rating does not exceed 150°C (302°F). Uncoated or tin/lead alloy coated or tin-coated solid copper conductors and uncoated or tin/lead alloy coated or tin-coated copper strands whose diameter is at least 0.015 inch or 0.38 mm are for products whose temperature rating does not exceed 200°C (392°F).UL 66 pdf download.