The dielectric withstand voltage (DWV), sometimes referred to as the “Voltage Proof Test” or “Wet Dielectric Test”, is perhaps one of the most referenced tests when examining wires. The reason is that the test performs the most important part in wire insulation assessment: it determines if the wire insulation is free of breaches (or has been sufficiently degraded such that a high voltage would breach any insulation weak points). The basic concept of the DWV test is that the entire wire, except for two inches at both ends, is placed in a water bath and a high voltage potential is placed between the conductor and the return electrode in the water bath. If there is a failure in the insulation, then there will be a noticeable current flow.
The following parameters can be modified for this test for an additional fee:
Pretest soak time
Voltage type (AC or DC)
Applied voltage duration
Voltage frequency on specimen
Perform visual examination of the specimen. Record any defects.
Strip 0.5 inches of insulation from both ends of the specimen and twist together.
Place specimen in a water bath with the ends secured above the water. Let sample soak for the specified duration.
Attach specimen ends to the test circuit leads.
Turn on test system voltage and slowly increase to desired voltage.
Allow system to stabilize at maximum voltage. Record voltage and leakage current.
Slowly lower the applied voltage.
Report the specimen length, maximum voltage, and maximum current from the test.