188.8.131.52 IR Test
The accuracy is based on the test conditions chosen to measure the insulation resistance, and is given as:
AT = AR +AC+AI+AZ
AT is the total accuracy (%)
AR is the basic relative accuracy (%)
AC is the calibration accuracy (%)
AI is the correction for current level (%)
AZ is the correction for impedance level (%)
The value of AR is given in the table in section 1.1 of this chapter.
The values of the other factors are given below.
AC = 0.03%
AI = 3.2% + (0.000002% / IM )
AZ = 0.5% + (0.001% x ZM )
IM is the measured current (A)
ZM is the measured IR value (MΩ)