It would probably be a good idea to have the rest of your domestic electrical wiring checked out as well. Shoddy workmanship at the circuit breaker probably indicates other safety issues for your domestic wiring. The US domestic wiring will be different to the UK standards but a socket tester such as this one at

http://www.martindale-electric.co.uk/sockets.htm

will test for the correct socket polarity and earth leakage problems. There should be a US equivalent tester to test for wall socket wiring problems.

Having a Residual Current Circuit Breaker RCCB installed is highly desirable as well.

http://en.wikipedia.org/wiki/Residual-current_device

They are known life savers protecting against lethal electrocution.