UL 988-2020 pdf download

UL 988-2020 pdf download.Humidifiers.
20.13 A lead shall not be more than two AWG wire sizes smaller than a copper supply conductor to which it is to be connected. 20.14 It shall be assumed that wire having the specified temperature rating will be installed for the power-supply conductors to a product marked in accordance with Clause 78.1. Otherwise, it shall be assumed that 75°C (167°F) wire will be used. 20.15 Field-wiring terminals shall be acceptable for copper supply conductors or for either aluminum or copper supply conductors, in accordance with the marking required by Clause 78.2. 20.16 The distance between a pressure terminal connector intended for field wiring and the wall of an enclosure toward which the conductor is directed or through which the conductor might pass shall be as specifed in Table 8. Table 8 shall not apply where a wall or other obstruction lies outside the area occupied by a conductor that is bent or deflected to a radius not less than the distance specified in Table 8. 20.17 A permanently connected product intended for connection to a grounded power-supply conductor and employing a lampholder of the screw-shell type, a single-pole switch, or a single-pole automatic control shall have one terminal or lead identified for the connection of the grounded conductor of the supply circuit. The identifed terminal or lead shall be connected to the screw shell of each lampholder and shall not be connected to any single-pole switch or single-pole overcurrent protective device other than automatic controls without a marked “off” position. 20.18 A terminal intended for the connection of a grounded power-supply conductor shall be made of, or plated with, a metal that is substantially white in color, or be identified by the word “white” or the letter “W” marked next to the terminal, The terminal shall be readily distinguishable from the other terminals, or proper identification of the terminal shall be clearly shown in some other manner, such as on an attached wiring diagram.
21.8 If a switching device or a pilot device that controls a switch operates to interrupt the main supply circuit, it shall, when open, disconnect all ungrounded power-supply conductors. 21.9 The attachment plug of the power supply cord of an appliance provided with a 15- or 20-ampere general-use convenience receptacle shall be of the 3-wire grounding type. The attachment plug of the power supply cord of an appliance provided with either a manually operated, line-connected, single-pole switch for appliance on-off operation, or an Edison-base lampholder shall be of the polarized or grounding type. 21.10 When a 3-wire grounding-type attachment plug or a 2-wire polarized attachment plug is provided, the attachment plug connections shall comply with Figure 8, and the polarity identification of the flexible cord shall comply with Table 10. 21.11 The conductor of the power supply cord that is intended to be grounded shall have the screw shell of an Edison-base lampholder and the terminal or lead receptacle intended to be grounded connected to it. Table 10 identifies the supply cord conductor intended to be grounded. 22 Strain Relief 22.1 Strain relief shall be provided so that a mechanical stress on a flexible cord will not be transmitted to terminals, splices, or internal wiring. See Strain-Relief Test, Clause 62. 22.2 A metal strain-relief clamp or band without auxiliary protection shall be acceptable with a Type SJ, SJO, SJT, SJTO, S, sO, ST, or STO cord. A metal strain-relief clamp or band shall be acceptable with Type SP-2 or lighter duty rubber-insulated cord, and Type SPT-2 cord, only if auxiliary nonconducting mechanical protection is provided over the cord. 22.3 Unless previously investigated and found to be acceptable, a clamp of any material is not acceptable for use on a Type SPT-2 or SVT flexible cord. For a heavier duty thermoplastic-insulated cord, a clamp may be used. In such cases auxiliary insulation is not required unless it is judged that the clamp may damage the cord insulation. UL 988-2020 pdf download.