Last night the halogen hob turned itself off after having been on for about an hour. After a while we managed to turn it back on and continued cooking for a further 10 minutes at which point it turned itself off again. At this point we also noticed that the cooker isolation switch was smoking a little bit and was very hot. Turned the switch off and isolated at the main fuse box. This morning I'm wondering what the best way to proceed is. I'm happy enough changing sockets and fitting lights etc, and so would be happy enough replacing the switch if that's all thats involved. Otherwise I'll get an electrician in to take a look. Any advice appreciated.