A bare CTI number can be read wrong. “CTI 400” looks like a clean result until you learn it was run with the aggressive contaminant, or that the 100-drop figure sat 50 V lower, or that erosion ate 3 mm off the specimen while it passed. All of that lives in the report — and a compliant report… Read More: How to Read a CTI and Tracking Test Report »
The specimen decides the number almost as much as the material does. A tracking test measures how a surface behaves under a contaminated film, and nearly every rule about how you cut, clean, and condition that surface exists to stop the specimen itself from becoming the variable. Get the prep wrong and the result is not slightly off… Read More: CTI Test Specimen Preparation Guide (IEC 60112 & 60587) »
The drop test tops out. IEC 60112 discriminates between poor, moderate and good tracking resistance for indoor equipment under moist conditions, and for that job it works. But it runs at hundreds of volts on 20 mm specimens for under an hour, and its own scope says the results do not qualify a material for outdoor service. Outdoor… Read More: IEC 60587 Inclined Plane Test: Tracking and Erosion »
CTI tells you what a material can do. PTI tells you whether the part in front of you still does it. The two come out of the same machine, run the same drops of the same electrolyte across the same platinum electrodes. The difference is the question. CTI hunts for a ceiling. The proof tracking index checks a… Read More: Proof Tracking Index (PTI): IEC 60112 Acceptance Test »
Insulating material does not have to break down through its bulk to fail. It can fail across its face. A thin film of dirty water, a few hundred volts, and enough time will burn a conductive path into a plastic surface that measured hundreds of megohms when it was clean. That path is called a track. IEC 60112… Read More: Comparative Tracking Index (CTI): IEC 60112 Test Method Explained »