Abstract: Creepage distance and clearance test is a basic test item for compulsory certification of electrical products. Laboratories can verify and improve their testing capabilities in relevant testing fields by participating in proficiency testing. CNAS requires laboratories to regularly participate in proficiency testing in related testing fields. In the process of proficiency verification of clearance and creepage distance, it is necessary to pay attention to the selection of appropriate test equipment, and to select the preferred path considering standard requirements and prior technical decisions. Participating in the proficiency verification of creepage distance and clearance test will help to understand the laboratory's understanding and mastery of standards, and improve the laboratory's specific knowledge of creepage distance and clearance.

Key words: Clearance, Creepage distance, Proficiency testing