extractor fan

Just bought my first 3d printer, voxelab aquila c2. I have just ordered a cover as the usual excitement of using a new toy meant I spent too much time in 1st 48 hours watching it perform. May be unrelated but got quite headache. (Please no scary stories about 3d printer dangers - I am generally...

I have an ancient, noisy extractor fan in the bathroom which is controlled by a pull switch. It is fed by four wires (Earth, Neutral, Live and Switched Live). If you pull the cord twice to turn it on and immediately off again the fan carries on running for a while - which is good. However, if...

In our bathrooms and the kitchen, we have extactor fans which are constantly powered but triggered on high speed when the lights come on. The lights are the usual switched Live, with permanent Neutral. The fans have their own isolated Live and Neutral, with a feed from the light Switched Live...