Zhilitong Electromechanical Co.,Ltd

Product Testing Machine Manufacturer

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The relationship between group of insulating material and CTI

According to IEC60950, creepages distance shall be so determined that , for given RMS working voltage and pollution degree ,no flash over or breakdown of insulation (for example ,due to tracking ) will occur .

So . 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 Illa  175 ≤ CTI 〈 400
Material Group Illb  100 ≤ CTI 〈 175

The material group is verified by evaluation of the test date for the material according to IEC60112 using 50 drops of solution A .

Zhilitong Electromechanical Co., Ltd manufactures tracking index tester ZLT-LDQ1 which is complying with IEC60950 standard. 


Tracking Index Tester