Is it safe to plug USB devices on 220v wall sockets?

"I just want to know if it is safe to
use those wall socket chargers for USB
devices?

Short answer: Yes

Long answer:

The usb spec tells us Vbus = 5VDC, and then the device can start with 0.1A (but the device ""can ask"" for as much as 0.5A).

The wall socked should transform 220VAC into 5VDC.

Please note that a lot of those wall sockets that short-circuit D+ and D- and then you don't have to negotiate how much current you can draw (and as much as 1A should be ok).

If you are unsure, just use a multimeter and check that the wall socket provides 5VDC.

Good luck."

"works for me. Probably you should check your device for 110-240 (or 220) written on it. Those tiny USB adapters that came with my iPhone in the US, work fine in Europe... I just need an adapter plug to be able to plug it into the socket.

Also I brought over from the states a Belkin ""thing"". dunno how to describe it, it is kind of like a brick with a bunch of power sockets. So like a mini powerbar, but with 2 usb ports also. That also works in Europe to power my iPhone dock and iPhone/iPod universal docks. After I plug it into the wall with a plug adapter."