Megger testing

[FaradayFF]

Greetings,
When conducting a megger test on a system that is comprised of insulated cables that transition to bare bus bars, can this test still be performed in lie of the fact that we're not solely testing the insulated cables but also a portion of the exposed bus bar that is part of the test setup.
My impression was that Megger test were effective in reading the insulation resistance for systems that were insulated, I may be wrong on that.
I'd appreciate your thoughts on this.
Thanks,
EE

 

[hillbilly1]

Yes, you would also be testing the insulators that the buss bars are attached. If your testing for a failure, and it does fail, then the wires would have to be removed to determine which part has failed, the wire, or the buss bar insulator.

 

[WasGSOHM]

reading the insulation resistance for systems that were insulated,

Air is the insulator for an ungrounded bus bar, no?

What is the highest test voltage for your megger?

 

[retirede]

Air is the insulator for an ungrounded bus bar, no?

It has to be mounted somehow. That’s what the megger would be checking.

 

[paulengr]

At least in theory one of the switchgear tests is the “tinfoil test”. Wrap all the insulation in aluminum foil then Megger it. This gets rid of the air gap and measures raw tracking.

 

[WasGSOHM]

And the Megger leads go between the tin foil and the conductor?