[off-topic] Powered USB Hub

[Jim Householder]

Hi,

I bought a USB 3 powered hub from Woolworths for $17 to use with my 
Raspberry Pi.  I've used the same model with my Toshiba notebook with no 
problems.

The odd bit is that when I plug the powered hub into the R-Pi, it powers 
it up.  I would have expected the power in the hub to go only to its 
ports and not back up the line to the computer.

Is there a risk of problems if the hub's nominal 5 volts is marginally 
higher than the computer's supply and electrons flow the wrong way?

Thanks
Jim