UL 1238-2022 pdf download – Control Equipment for Use with Flammable Liquid and LP-Gas Dispensing Devices.
29 General 29.1 Live screwheads or nuts on the underside of a base shall be countersunk not less than 1/8 inch (3.2 mm) in the clear, and then covered with a waterproof, insulating, sealing compound that will not melt at a temperature 15 °C (27 °F) higher than the normal operating temperature of the device, and at not less than 65 °C (149 °F) in any case, except that when such parts are staked, upset, or otherwise reliably prevented from loosening, they are not required to be recessed, and they can be insulated from the mounting surface by material other than sealing compound or by the provision of spacings through air and over surface as required in this standard. 29.2 The spacing at wiring terminals is to be measured with appropriate wires in place and connected to the terminals as in actual service. 29.3 All uninsulated live parts connected to different circuits shall be spaced from one another as though they were parts of opposite polarity and shall be judged on the basis of the highest voltage involved. 29.4 The spacings between field-wiring terminals of opposite polarity and the spacings between a field- wiring terminal and any other uninsulated metal part (dead or live) not of the same polarity shall not be less than indicated in Table 29.1.
29.6 Primary-circuit spacings apply in all secondary circuits supplied by a transformer winding of 200 volt-amperes or a higher capacity (maximum available power) at a potential higher than 100 volts. The spacings in all other secondary circuits are judged on the basis of the dielectric withstand test described in 37.3. 29.7 The spacings in Table 29.2 and Table 29.3 do not apply to the inherent spacings of a component of the control equipment, such as a snap switch. The acceptability of spacings on a component is based on the requirements that cover the component. For a repulsion motor, a repulsion-induction motor, or a repulsion-start induction motor, the spacings in Table 29.3 do not apply to the commutator, the brush assembly, or the jumpers that short-circuit the brushes. Any uninsulated conductor in the rotor circuit is regarded as a dead-metal part with respect to the stator circuit, and the appropriate spacing is required between the uninsulated stator and rotor conductors. 29.8 Vulcanized fiber or a similar material employed where spacings are otherwise insufficient shall comply with Insulating Barriers, Section 22. Exception: Vulcanized fibercan be used at one-halfthe thickness indicated in Section 22 when it is used in conjunction with at least 50 percent ofthe required airspacing forairalone.