The purpose of this article is to explain the reason for getting ERRO results using the Fluke-1555.
The Fluke-1555 has a straightforward Insultation Test function as well as two other functions called the Polarization Index Test (PI) and Dielectric Absorption Ratio Test (DAR).
The (DAR) test is an overall one minute test and compares two readings one at the 30 second point and the other at the 60 second point and the results are a ratio between the two measurements.
The (PI) test is an overall 10 minute test and compares two readings one at the 1 minute point and the other at the 10 minute point and the results are a ratio between the two measurements.
Below is a table showing anywhere between Dangerous to Excellent results. If the results are a higher number than 1.6 for the (DAR) test or higher than 4 for the (PI) test the Fluke-1555 will show ERRO. Granted normally ERRO results would indicate something is wrong but in this case it’s Excellent.