Technical data

APPENDIX
CV ELECTRICAL POWER SYSTEM MAINTENANCE MANUAL 2A5A2-ELEC-MM-1-0 48
Minimum Required Insulation Resistance Values for Observed Test
Temperatures
Range of Test Temperature Observed Required Minimum Insulation
Resistance Reading
Degrees F Degrees C Megohm
41–50 5–10 40
50–59 10–15 30
59–68 15–20 20
68–77 20–25 15
77–86 25–30 10
86–95 30–35 7.5
95–104 35–40 5
Dielectric Absorption Ratio
8. If the insulation resistance of any measurement taken at 30 seconds is less than
full scale, then calculate and record the dielectric absorption ratio, by dividing the
measurement at 60 seconds by the measurement at 30 seconds.
Example:
Measurement at 30 seconds = 20 megohm
Measurement at 60 seconds = 50 megohm
Dielectric Absorption Ratio is 50/20 = 2.5
9. If the Dielectric Absorption Ratio is less than 1.3, replace the cable.
0.