Went to my brothers today to try and help with his lighting problem.The light in his hall which is on its own switch and and his up stairs landing light which is 2 way switched from hall and landing have stoped working, all other lights work fine.I first isolated at main cu breaker and checked connections at ceiling roses and switches and then energised circuits end tested at roses with fluke voltage tester.At hall rose:- 0 volts live- neutral and earth but 50 volts neutral- earth.I turned off lighting M.C.B.s but still got 50 volts as befor,I then turned off other M.C.B.s and lost the 50 volts when I turned of the B32 downstairs ring breaker.I also checked other downstairs working light roses for good connections.Please does anyone have any suggestions befor I resort to calling in a qualified electrician.By the way the house is about 20 years old and no nails or screws driven into walls in the recent past.Any suggestions would be very much appreciated.