Impulse Test on LV system

Because what's the probability that a sharp rise time steep front impulse wave similar to lightning is going to reach your low voltage equipment after it's traveled from the transmission line, past a lightning arrester or two, through a few transformers, past a surge arrester or two, and into your switchgear without having a lot of the energy taken out of it?

Dear Sir,

Thanks for that update.

...and because it doesn't say "carry this out" in the equipment Standard Test Procedure.

It is still only an option in the latest standard for LV switchgear (IEC 61439-1:2011), not mandatory i.e. alternative methods can still be used which are usually cheaper.

It was always considered a type test rather than routine, but is very useful in searching out hidden mistakes or degraded insulation. Not always easy to perform other than in workshop/lab conditions.

Dear All,

I am really thankful to all the people who replied to my question. I got an idea about this aspect now. Thanks.

Dear All,

Thanks for all your clarification.