UL 1581 Reference Standard for Electrical Wires, Cables, and Flexible Cords
1.1 This Standard contains specific details of the conductors, of the insulation, of the jackets and other coverings, and of the methods of sample preparation, of specimen selection and conditioning, and of
measurement and calculation that are required in the Standards for Thermoset-Insulated Wires and Cables (UL 44), Thermoplastic-Insulated Wires and Cables (UL 83), Flexible Cord and Fixture Wire (UL
62), and Service-Entrance Cables (UL 854). Elements of this Standard are referenced in other requirements as well.
1.2 The requirements for the particular materials, construction, performance, and marking of an individual type of wire, cable, or flexible cord are stated in the Standard covering the finished type. They are not part
of this reference Standard.
1.3 In each case in which an element of this Standard does not apply, the Standard covering the finished type so states and specifies what does apply.
1.4 A product that contains features, characteristics, components, materials, or systems new or different from those covered by the requirements in this standard, and that involves a risk of fire or of electric shock
or injury to persons shall be evaluated using appropriate additional component and end-product requirements to maintain the level of safety as originally anticipated by the intent of this standard. A
product whose features, characteristics, components, materials, or systems conflict with specific requirements or provisions of this standard does not comply with this standard. Revision of requirements
shall be proposed and adopted in conformance with the methods employed for development, revision, and implementation of this standard.
2 Units of Measurement
2.1 In addition to being stated in the inch/pound units that are customary in the USA, each of the requirements in this Standard is also stated in units that make the requirement conveniently usable in countries employing the various metric systems (practical SI and customary). Equivalent – although not exactly identical – results are to be expected from applying a requirement in USA or metric terms.