[mactec54]

YAGQ (yet another grounding question). My Huanyang HY01D523B 220v 1.5kw has an additional two grounding screws located outside the normal rows of connecters. There is one on each side, and has a ground symbol embossed into the plastic. Its the same ones talked about in this video (jump to 5:15):

https://youtu.be/PFe7VfTXp7o?t=316

In that video he says they should be tied to ground. But in my case there is no continuity between either one, or to the main grounding post with the ground symbol (labeled in the manual earth ground). They also dont connect to DCM or ACM. To me those screws just look like assembly screws holding on the plastic. But without taking the unit apart, I can't say for sure they are conductive to anything. Also the manual mentions nothing about them.

Has anyone run into this? It is odd they have a ground symbol.

They are using just a Plastic case that many different manufactures use your observation that they are not connected in any way is correct on some as that manufacture is not using them at all, so a Big Caution to anyone that watches videos like this

You would never connect them together even if they where an active Ground point

The Ground on all VFD Drives is the Heat sink of the VFD Drive, which in some cases is covered by the plastic case