Hey everyone, when doing insulation testing on circuit breakers. When I test the breaker open, I typically just go from line to load. And I am not grounded out the other poles
In this book, Paul, Gill‘s electrical power, equipment, maintenance, and testing it is saying for circuit breakers open connect high voltage lead to pull one. Ground all other poles repeat for poles two through six and turn with other poles grounded.
I have been taught incorrectly? I am trying to do everything to the best of my ability and down the road teach the new tech how to do it properly.
What’s everyone’s thoughts?
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When you perform the phase-to-phase tests, are you grounding the phases not under test? What is your preferred order for testing? Perform “closed” tests first, and finish with “open” tests?
I always perform an “open” insulation resistance test or hipot test as the very last test on a breaker. The last thing I want to do is very the breaker is actually open before I rack it in a cubicle. I use a cluster of test grounds that has 6 clamps. 3 clamps for the load side, 2 for the line side not under test, and 1 to the frame.
If you operate on my principle, jumping the load side to the phases on the line side not under test ensures that in any order of testing, you always verify that all items are not energized with a change of state. It also ensures that a change of state in the breaker wouldn’t magically fault phase to phase on the line side. Its unlikely, but anything is possible.
Bottom line, Paul Gill’s method is the proper method for 100% ensuring a breaker is electrically safe to energize.
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