Repeated high-voltage isolation testing of a barrier component can degrade the isolation capability, depending on materials, construction, and environment. The DCR01 series of DC/DC converters have toroidal, enameled, wire isolation transformers with no additional insulation between the primary and secondary windings. While a device can be expected to withstand several times the stated test voltage, the isolation capability depends on the wire insulation. Any material, including this enamel (typically polyurethane), is susceptible to eventual chemical degradation when subject to very-high applied voltages. Therefore, strictly limit the number of high-voltage tests and repeated high-voltage isolation testing. However, if it is absolutely required, reduce the voltage by 20% from specified test voltage with a duration limit of one second per test.