Hello,

Is the RB750UP grounded at the ethernet ports?

Regards,

yes

It has shielded UTP ports but is not grounded.

I would like to clarify a terminology misunderstanding. "Grounded" means "connected to building grouding infrastructure through a grounding wire". Device can't be "grounded" out of the box, you have to connect it to some grounding installation. As the RB750UP has shielded ports, this means you can use Shielded Ethernet cable, and connect the shield to a grounding installation. Please see more informationin this page: http://wiki.mikrotik.com/wiki/Manual:Grounding