[Shuie]

The white should be the neutral, but there is no way to tell how thats been wired without a meter. You can tie it to ground and then check to see that the circuit reads 220v on the meter. If so, then its the neutral.

disclaimer: I am not an electrician. all I know is that if you tie the neutral to ground, you get a 220V socket that will smoke a 120V appliance. Good luck.