UL-353:2011 pdf free download – Underwriters Laboratories Inc. Standard for Safety Limit Controls.
8.3 Vulcanized fiber may be used for insulating bushings, washers, separators, and barriers but not as
the sole support for uninsulated current-carrying parts of other than low-voltage circuits.
9 Field Wiring Con tie clion S
9.1 General
9.1.1 In 9.1.2— 9.3.1 and particularly where wiring terminals or leads are mentioned, wiring connections are considered to be those that are made to the control when the control is installed in the field.
9.1.2 A control shall be provided with wiring terminals or leads for the connection of conductors of at least the size required by the National Electrical Code ANSI/NFPA 70, corresponding to the rating of the control.
9.1.3 A terminal box or wiring compartment shall be so located that wire connections therein will be accessible for inspection, without disturbing either high-voltage or safety-circuit wiring, after the control is installed in the intended manner; except that for an outlet box mounted control, wire connections may be accessible upon removal of the control from the outlet box.
9.1.4 A wiring space or compartment intended to enclose wires shall be free of any sharp edge, burr, tin, moving part, or the like that may abrade the insulation on conductors or otherwise damage wires.
9.1.5 A lead shall be Type T wire or wire having insulation equivalent in electrical and mechanical properties to Type T wire. A lead shall have a free length of at least 6 inches (152.4 mm).
9.1.6 A field-wiring lead, other than a lead for connection of a Class 2 circuit, shall not be more than two standard wire sizes smaller than the copper conductor to which it is intended to be connected, and shall not be smaller than 18 AWG (0.82 mm2).
Exception: The lead may be more than 2-wire sizes smaller than the copper conductor to which it is intended to be connected in the field, but shall not be smaller than 18 A WG (0.82 mm2), if more than one factory-provided copper lead is intended for connection to the same supply lead, and the construction complies with all of the following conditions:
a) A wire connector for connection of the supply wire is provided as part of the unit or remote control assembly, and the wire connector is intended for use with the combination of wires that will be spliced.
b) The factory-provided leads are grouped in a manner that prevents stress on an individual lead.
c) The product is marked in accordance with 45.6.
9.1.6 revised September 30, 2010
9.1.7 A lead provided for connection to an external line-voltage circuit shall not be connected to a wire-binding screw or pressure terminal connector located in the same compartment as the splice unless:
a) The screw or connector is rendered unusable for field-wiring connection; or
b) The lead is insulated at the unconnected end and a marking on the unit clearly indicates the intended use of the lead.
9.1.8 The free end of any lead that will not be used in every installation, such as a tap for a multivoltage transformer or one free lead for a single-pole, double-throw switch, shall be insulated. For an equipment grounding lead, see 9.1.11.
9.1.9 Leads for field connections shall be provided with strain relief to prevent mechanical stress from being transmitted to terminals, splices or interior wiring. Each lead shall be capable of withstanding for 1 minute a pull of 10 pounds (4.45 N).