Your electrician needs to check the sockets.

There are many sources for that issue but the most common cause is the miswired socket. It's quite dangerous so either research it or have your electrician check it out.

Here's the small device I use to double check the sockets.

http://www.amazon.com/GE-50542-Receptacle-Improper-Indicator/dp/B002LZTKIA/

Bob