This is incorrect. Or at the very least, imprecise. Most electronic devices connect the outer case to common ground. This is because if there ever is a short circuit to the case, it drastically minimized the odds of electrocution.
If there is a difference in potential between common ground and yourself, you may very well feel it, and it indicates a possible wiring issues in your house. On the plus side, the difference should be fairly minimal.
However, if this is what the OP is talking about, I can't say. I suspect it's more to do with the housing being vibrated at a high frequency, perhaps by the battery or other charging circuitry.