What is the recommended minimum duration of a VLF maintenance test in accordance with NETA standards?

The recommended minimum duration of a VLF (Very Low Frequency) maintenance test is set at 30 minutes in accordance with NETA standards. This duration allows sufficient time to effectively assess the insulation integrity of the system being tested. A 30-minute test ensures that any potential insulation failures or weaknesses can be detected, as it provides enough time for the electrical stress application to reveal faults that may not be visible during shorter testing periods. By adhering to this standard, technicians can gain a better understanding of the condition of the insulation and ensure the reliability and safety of electrical equipment.