I have just fitted a number of new lights at home. One of these is in the bathroom. I have about 7 wires linked to the house loom. 3 of these are black, two others have red tape and one earth. I thought I had connected up the fitting in the same way as the old unit. This used to come on with a pull switch. I also have an extractor fan that only operates from the main isolator switch outside the bathroom. I had the two red taped wires linked to the blue wire, the three balck wires togther and the earth capped off as there is no connection in the new light. However when I turn the light on the extractor goes off and when I turn the light off the extractor goes on. I have now moved the blue wire to join the blacks and I seem to be back to where I started. The new light works fine and the extractor only comes on when I switch the isolator switch. I am not unhappy with this (although my plumber tells me that the fan should come on with the light). I guess I have worried myself and I am now doubting that the installation is safe. No trips have blown, it all works fine, I have cheked the fitting with a meter and there is notheing live around the light. Do you think I need to get the installation checked to put my mind at rest or would the trip have blown if I had done something wrong?
If I have it right the extractor overrun timer or humidity sensor is faulty and does not turn off which means you have to turn it off with the isolator. I see no danger in this. Although it does not do the job.
Your re-wire experiment putting extractor and light in series is not a good idea and new sensor or complete extractor is only real cure.
Please remember I am guessing on what you have done and only real way to be certain is to have someone look at what you have but as far as I can work out by what you have said there is no real problem.
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