USB Earth connected to Digital GND

[dmccric]

I have taken some equipment for EMC Testing and was zapping the machine with 4kV with an ESD Gun and my USB communications failed.
The problem was that when I insert the USB cable the Earth and GND are connected on the PC side. When I remove the cable it is ok. Unfortunalty I need the USB cable connected for the test.

Has anyone had any similar problem?

 

[HTA]

A workable solution could be to use an isolated USB connection. Either as a complete component, like this: **broken link removed** , or build your own with components ( like **broken link removed** ).