Bathroom fan wiring

[diy_master]

I need to replace an existing fan which has 3 wires and earth. They are red blue yellow. The new fan i have needs switched live, live and neutral. I have a fluke voltage pen so can i just identify which is the switched live cable by putting switch on and seeing if pen bleeps and then turning switch off and seeing it doesnt bleep? Live should be detected by the pen bleeping? Neutral will be the only wire that does not bleep when using the pen?

 

[westward10]

Do you have a pic of the existing fan connections. Please say you haven't already removed it
Voltage pens whilst useful are extremely unreliable.

 

[diy_master]

Do you have a pic of the existing fan connections. Please say you haven't already removed it
Voltage pens whilst useful are extremely unreliable.

See attached. I turned the fan on then turned off the relevant fuse and the fuse box and then used the fluke detector to double check. Still havent removed it though. I thought fluke is well regarded?

 

[westward10]

Are the terminals marked on your new fan or a model/part no.

 

[diy_master]

Are the terminals marked on your new fan or a model/part no.

Yes they are marked on the new fan as live neutral and switched live. They are not marked on the current fan

 

[westward10]

The general connection will be blue, neutral. Red, live and yellow, switched live.
ENSURE IT IS ISOLATED and let us know if this is correct.

 

[diy_master]

The general connection will be blue, neutral. Red, live and yellow, switched live.
ENSURE IT IS ISOLATED and let us know if this is correct.

It has an isolater switch that means i can run the lights only but at the moment its set so that when i switch on it turns on lights and fan. If i take the answer you gave and connect new fan can anything bad happen if the wires are in the wrong place ? I googled but cannot find this general connection colour you mention...is there any where online this is written?

 

[westward10]

99% certain I am correct. Do you know the make and model no of the existing fan.

 

[diy_master]

99% certain I am correct. Do you know the make and model no of the existing fan.

Its manrose fan with humidistat but i have looked all over it and no sign of a model number written on it.

 

[westward10]

I am certain I am correct but if in doubt consult an electrician.

 

[diy_master]

Thank you so much. Can i test this using the fluke pen to be double sure as per below method?

identify which is the switched live cable by putting switch on and seeing if pen bleeps and then turning switch off and seeing it doesnt bleep? Live should be detected by the pen bleeping? Neutral will be the only wire that does not bleep when using the pen

 

[westward10]

I can't recommend the volt pen as a suitable means of identifying the wires they are too unreliable.