[chbot] Insulation Tester

[Synco Reynders]

I'm no expert although I was told the import aspect of insulation testing
is the duration of the reading - a reading should be at least 1minute, up
to 10 minutes for large equipment... and the resistance should always
increase. The Megger manual (
https://www.instrumart.com/assets/Megger-Guide-to-Insulation-Testing.pdf
page 15)  suggests sampling at the 60 second and 30 second marks and using
the ratio.
/s


On Mon, 25 Jan 2021 at 11:33, Mark Beckett <m.beckett at amuri.net> wrote:

> A word of caution about testing cables well beyond their rating.
>
> It punches holes which later become a problem.
>
> We have a number of communication cables that are 120v rated, and were
> tested using 500v meggers. We're now seeing many fail.
>
>
> Mains cables and devices are tested at twice their rated design (ie
> 500vDC) UNLESS it has a specification to only test at 250VDC.
>
> *We have a number of power supplies that have protection devices rated at
> 250v.*
>
>
> Tenma make a low cost fully rated device that sometimes appears on special.
>
>
> https://nz.element14.com/tenma/72-9400a/insulation-tester-1kv-5gohm/dp/249951801
>
>
> Mark
>
> On 25/01/21 00:49, Andy Gardner wrote:
>
>
> On 24/01/21 10:41 pm, Mark Atherton wrote:
>
> The modern insulation used on enamelled copper wire (even the thin stuff)
> seem to tolerate 5kV OK. I have also tried the lowest voltage cable I could
> find (CAT5) and strapped a twisted pair across the unit at full smoke
> without incident.
>
>
> Cat 5 has polyethylene insulation rather than the more common PVC.
>
>
>
>
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