题目

请教一下 PCB 的CTI 是多少?在60950-1 clause 2.10.4.2 中它是属于哪个 material group?

提问时间：2022-04-29

答案

主要是250以下,400和600的也有.
PCB的CTI等级有很多,等级越低,相对应的距离越严.
不知道就当作GOUPB吧.
CTI 需要做漏电起痕试验来确定.
安规试验一般做法是按最严酷情况处理,即默认为 Ⅲb.
标准原文请参考:
2.10.4.2 Material group and comparative tracking index
Material groups depend on the comparative tracking index (CTI) and are classified as follows:
Material Group I CTI ≥ 600
Material Group II 400 ≤ CTI < 600
Material Group IIIa 175 ≤ CTI < 400
Material Group IIIb 100 ≤ CTI < 175
The material group is verified by evaluation of the test data for the material according to
IEC 60112 using 50 drops of solution A.
If the material group is not known,Material Group IIIb shall be assumed.