For a few days our bathroom has smelt horrible, like rotten fish. I thought the drains were playing up so I tried bleach e.t.c. to get rid of the smell but nothing seemed to shift it. I googled to see what else I could try and to my amazement I found out that when wires are melting/burning they cause this horrible smell. I turned the electric off and climbed up the stepladder to investigate and sure enough the smell was from the pull cord on/off box. I called the electrician and when he looked in the box the wires were loose and the red wire has turned black!! You may already know this but I didn't so I thought i'd share. Not sure the best place to post this.