MV Air CB HiPot Test

[farmape]

Two Questions:
1. What is preferred source (AC or DC) for a dielectric withstand voltage test of an air M.V. C.B.
My thought is AC (assuming the service voltage is AC)
2. NETA MTS lists the HiPot as an optional electrical test (for an air MVCB), with the CB closed. Is there a reason the test across open poles isn't listed? I understand prescribed maintenance would verify the gap and inspect the arc chutes ... but why not test at an elevated voltage?
Thanks!

 

[DTR2011]

If I recall correctly, an Insulation Power Factor / Dissipation Factor is the preferred test to diagnose the quality of the ACB. This is generally performed with the arc chutes raised and lowered.

 

[Zogzog]

PF is the prefered test and the reason the open pole test is not listed is that is called a vacuum ingrity test and is generally tested at a lower voltage specific to the bottle (Listed in the IB)