UL 810B-2016 pdf download – Standard for DC Power Capacitors.
4.3.4 With regard to mechanical strength, aging characteristics, and resistance to distortion at maximum temperatures of operation described in 4.3.3(a), (f) and (g), a polymeric material used as an enclosure shall have a relative mechanical temperature index without impact of at least 70°C (1 58°F) or the marked temperature rating, whichever is greater, in accordance with the Standard for Polymeric Materials – Long Term Property Evaluations, UL 746B. With regard to the moisture-absorbent and dielectric strength properties described in 4.3.3(b) and (e), a polymeric material shall meet the requirements for dielectric strength as described in Table 6.1 of the Standard for Polymeric Materials – Use in Electrical Equipment Evaluations, UL 746C. 4.3.5 A nonmetallic enclosure material that also functions as an insulator shall comply with Insulating Material, Section 6. 5 Internal Protection Bridge 5.1 A polymeric material used as an internal protection bridge/pressure interrupter shall have a relative mechanical temperature index without impact in accordance with the Standard for Polymeric Materials – Long Term Property Evaluations, UL 746B, at least equal to that of the capacitor enclosure. See 4.3.4. 6 Insulating Material 6.1 A material used for the mounting of uninsulated capacitor terminals shall be a material rated for the application, and shall comply with the requirements specified in Table 6.1 . Exception No. 1 : A polymeric insulating material that is not rated for, or does not comply with, the hot wire ignition or high current arc resistance to ignition requirements in Table 6.1 shall not be used unless the part fabricated with the polymeric material complies with the applicable testing requirements outlined in the “additional consideration for materials not meeting pre-selection test performance levels” as prescribed in the Standard for Polymeric Materials – Use in Electrical Equipment Evaluations, UL 746C, Table 6.2.
6.2 Internal insulating materials shall comply with the requirements for the Dielectric Voltage-Withstand Tests, Section 1 4. Exception: Internal insulating materials for capacitors marked “unprotected” per 21 .1 (g) shall comply with the following requirements: a) Shall be classified HB minimum in accordance with the Standard for Tests Flammability of Plastic Material for Parts in Devices and Appliances, UL 94, or comply with the flammability – 1 2 mm flame test specified in the Standard for Polymeric Materials – Use in Electrical Equipment, UL 746C; b) Shall have a relative mechanical temperature index without impact of at least 70°C (1 58°F)or the marked temperature rating marked on the capacitor, whichever is greater, in accordance with the Standard for Polymeric Materials – Long Term Property Evaluations, UL 746B; and c) Shall comply with the requirements for dielectric strength criteria as described in Table 6.1 of the Standard for Polymeric Materials – Use in Electrical Equipment Evaluations, UL 746C. 6.3 A capacitor having a metal enclosure shall have an insulating liner of nonmoisture-absorbent material between the capacitor roll and the metal enclosure. In addition, the capacitor shall resist the absorption of moisture by having the capacitor roll completely immersed in a sealing compound or other material that may be used for the purpose.