The conduction of the chassis can be realized by the ground wire of the three-phase plug.
The reason why it is not easy to put it on foam plastic is actually because there are cooling holes in the lower part of the chassis, and the chassis absorbs the cold air from the outside through this cooling hole to achieve the effect of cooling. It is not recommended to put it on a hard platform, such as a table, because it will block the cooling holes and cause poor air circulation.