On the Vecow EMBC-5000, the system itself does not create a common ground between the I/O ports (such as USB, serial, and Ethernet) and the DC return. 
However, connecting external devices (such as USB, DVI-D, HDMI, or D-Sub) may introduce a common ground if those devices are already grounded through their own chassis. This can potentially lead to an unintended common ground condition or a short circuit.
Careful consideration of external device grounding is recommended when deploying the EMBC-5000 to prevent power loop or short circuit issues.