Intelligent Power Today Magazine

The 411 on DC testing of low-voltage circuit breakers

BY JIM WHITE, Shermco Industries, Inc.

The direct current (DC) overpotential test is one of the basic tests conducted to ensure an insulation system has adequate insulation life to make it to the next scheduled maintenance interval. While not a difficult test to perform, the test equipment used could have some serious deficiencies that may not be discovered unless the technician knows how to verify test...