按照UL8750：
7.7.1 Printed wiring boards shall meet the following criteria:
a) Conductive traces shall be bonded to the substrate for the minimum conductor width and
maximum unpierced area as required by the Standard for Printed-Wiring Boards, UL 796,
Exception: Printed-wiring boards that are completely encased in potting compound are permitted
to exceed their specified minimum conductor width or maximum unpierced area.
b) Temperatures measured in the temperature test of 8.3 shall not exceed the temperature
rating (RTI) of the substrate as determined by the Standard for Polymeric Materials – Long
Term Property Evaluations, UL 746B, and
c) Printed wiring board substrate flammability shall be no less than V-1 in accordance with the
Standard for Tests for Flammability of Plastic Materials for Parts in Devices and Appliances, UL
94.
Exception: A circuit supplied by a Class 2 or LVLE source need not comply.