I'm making a retro-fit device (so I have plenty of parameters that aren't in my control) where we're adding USB connectivity to the device for use with a PC.
The device is battery powered, and the battery configuration varies greatly from one user to the next.
There is concern that some users are using a battery holder that has exposed rivots that may come in contact with our USB connector's shield, thus shorting the battery's + and - with the shield material.
I'm less concerned with what happens to the device if they do this than I am for thier safety and what may potentially happen to their PC if I connect the shield in the usual way (ie. 1M res / 4.7uF cap between shield and ground). If I understand, the host side will have the shielding go directly to ground.
I'd want to be either a) comfortable that a short wouldn't be as tragic as I'm imagining or b) make electronic changes to my circuit board such that said short would be protected against, even if damage to my circuitry occurs so long as the user and PC are protected.
Unfortunately, due to previously mentioned constraints, I can't physically ensure the battery's poles don't come in contact with the USB shield, and I'm not soliciting responses to that effect. Of course I can warn the user by way of instruction manual and/or included notice to be careful if they use that type of battery holder, but if there's something I can do electronically I would like to know what it might be.