Re: OT - linux scanner USB cable plug causing sparks?

[paul schulz]

I've seen this where touching the metal shield on the outside of the  
plug, i can feel 50Hz, and measure about 100volts open cct. The  
scanner still worked though, and i put it down to a cheap power supply  
in the scanner. As Rex says, it will ground itself through the pc. You  
may start getting problems if the leakage is such that it starts to  
trip any earth leakage cct breakers upstream from where you are.

Paul



When plugging the usb cable in I bumped the end of the cable against the
metal plate on the back of my computer and noticed a small spark.