Standard Usb connector body connected to GND?

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    neazoi

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The focus of the question isn't clear. What has it to do with power electronics?

USB hosts usually connect the type A connector shell to the case ground respectively protective earth.

The USB spec isn't particularly clear in this regard (from USB 2.0)

USB 3.0 spec focusses on EMI requirements only. This sounds consequent because USB is SELV and no safety aspects are affected when grounding or not grounding the connector shell.
 

THe ground shield is normally connected to power ground pin, but in situations where ground faults or high return DC currents cause offset voltage or injected noise into the common mode ground, designers may choose different methods of grounding for special situations.

EMC is a two way situation for SMPS ingress with switching frequency noise modulated line frequency to the DC return which can induce a couple hundred uA current to grounded operator. Safe, but can be felt on the wrist or knee.
Or EMI can radiate on the USB I/O cable from the SMPS unless a CM choke is added. This allows a designer to add a wire and measure current between Shield and DC Return for EMC testing.
 
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    neazoi

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