Dielectric Strength Test Procedure

[ECSI]

Does anyone have a good written procedure for dielectric strength (hipot) testing of control panels? I'd like to incorporate a consistent test procedure that I could use myself and teach coworkers to follow the same procedure? In talking to different people in the same line of work as me we all seem to do things a little differently while testing. Thanks!

[Leitmotif]

1. Never megger yourself 2. Never meggere solid state components A lot of your decisions will be made based on what the voltage of your equipment is. I would check with Biddle http://www.biddlemegger.com/ They should be able to give you the relevant standards appropriate to your installation. Dan Bentler

[ECSI]

Yes, those are two key rules...lol. I learned #2 the hard way years ago.

[paulengr]

IEEE specifically no longer recommends use of Hipotting for testing due to the fact that it can cause damage and that there are better test methods out there. About the only thing it's good for is testing cable and connections, and the results are "fail/unknown". The damage it can cause on medium voltage cables (especially ones that have been in service) often does not show up for some period of time, and the test has NO predictive power...as in it won't pick up latent problems that may develop into something later. Meggering is not the same thing as Hipotting. Meggering is covered by IEEE standard 43.

[Andrew]

Just for clarification a "Megger" test and HIPOT test is not the same. UL/CSA States 1 minute test: Line Voltage X2 + 1000V 1 second test Line Voltage X2 + 1000V + 20% Words of advice Don't Hi-pot Low voltage lines (24V for example) Get an AC Hipot tester they are more forgivable then DC. Be gentle on relay coil wires (The relays will cycle repeatedly) Obviously DO NOT let yourself or anyone touch any metal surfaces while doing the test And obviously unhook your ground from your neutral line in the panel Edited December 1, 2010 by Andrew