Section 6.1 of ICEA S-81-570 specifies the wet insulation resistance stability qualification test. Cable specimens at least 10 feet long are immersed in tap water at rated temperature and energized at 600V AC. Insulation resistance is measured after 1, 7, and 14 days, then weekly for 12+ weeks.
The stabilization period is determined per ANSI/NEMA WC-53. Maximum rate of decrease per week is 4% (12 weeks) or 2% (24/36 weeks). This test verifies long-term insulation integrity under wet operating conditions.