Grounding of negative lead on SSTCs

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Marco.Denicolai-at-tellabs-dot-com 

Hi all,

I noticed on Dan's 15 kW SSTC schematics that the DC negative is
directly connected to the mains ground. I am used to see that done (and
do that) through a capacitor. I guess there is a safety issue here but I
can't recall the reason. Usually bench DC power supplies give the
possibily to externally ground the negative to the mains ground (and
chassis): it isn't readily wired.

Can anybody recall/explain the reason why to do it in one or another
way?

Regards