HIPOT testing 1

[Engineer2k7]

Hello Guys,

I have a question about HIPOT testing. I have seen a setup at work where they test insulation on the wire. The wire is immersed in saline. Essentially it is two wires which are soldered at one end and insulated accordingly.

From what i understand in order to do HIPOT test on such a setup you would need to raise the potential on both the wires ( or since they are soldered, its a single wire. So raise potential on one and leave other unconnected).

Anyways the question is doesnt the saline have to be in some kind of a metal bath (with the bath chassis grounded) to accomplish this? How does one close the circuit with just the wire in saline and no -ve or ground anywhere else?

 

[IRstuff]

You connect to the saline

TTFN

FAQ731-376

 

[Engineer2k7]

Hmm connect what to saline?

So the CL ions will lose electrons if there is a leakage and eventually at some point you have to replace saline?

 

[IRstuff]

Eventually, sure, but:
A. you're supposed to current limit, in any case
B. the test time is quite short

TTFN

FAQ731-376

 

[logbook]

The point is that insulation resistance is supposed to be tens of megohms. The saline solution will be probably be more like kilohms. So you connect one end of your insulation tester to the inside core of the wire under test and the other goes to the saline solution, which is intimately in contact with the insulation. Any slight crack in the insulation will show a massive leakage.

The electrode that goes into the saline solution will need to have good anti-corrosion properties.

 

[VEBill]

To make sure that the saline is connected, try a known-bad sample.

 

[subodhbhatnagar]

Yes!Engineer2K7! u can try testing a bad sample and adjust the over current device of the HIPOT Test Set to trip the test set by making it sensitive to trip and stop test if excessive leakage in found in your test case.Thus it will eleminate possibility of your apprehensions.
Also impress a test voltage which is approximately 80% of the fisrt commissioning/acceptance test made on the cable.
Sorry for being a late entrant in this thread.
Regards