CTI / tracking
This method is used to assess the relative resistance of insulating materials to tracking.
As a general rule, two different test solutions (A and B) can be used to investigate tracking.
| Test specimen | ≥20 mm x ≥20 mm x ≥3 mm |
| Test voltage | Between 100 V and 600 V (50 Hz) in 25 V steps |
| Test solution A (CTI A) | 395 Ωcm |
| Test solution B (CTI B) | 198 Ωcm |
| Drop volume | 20 mm³ |
| Failure criteria | Current on breaking ≥0,5 A > 2 s material burns |
Results of the test method:
- CTI (Comparative Tracking Index): highest voltage at which no test specimens fail during tests on five specimens after applying 50 drops in each case.
- PTI (Proof Tracking Index): voltage at which five specimens either pass the test with no failures or fail the test when 50 drops are applied in each case.
