The purpose of this article is to explain the reason for getting ERR results using the Fluke-1507.

The Fluke-1507 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-1507 will show ERR. Granted normally ERR results would indicate something is wrong but in this case it’s Excellent.