# Humidity sensor install



## HopelessDiyer

Hi,  Presently in my box I have a black and white wire coming out of the wall.   When I come to install the sensor it doesn't turn on the fan.   The red screw is for the fan control,  but I have no wire to put there...  Do i need to piggy back somewhere? 

View attachment 1482784062507.jpg


View attachment 1482784072163.jpg


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## nealtw

You are working with line and load wires, you also need the neutral.
[ame]https://www.youtube.com/watch?v=j82sBM9vWv8[/ame]


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## afjes_2016

Yes, you need the neutral (white) wire to work with but not the one that jumps from one switch to the other. That should either be black or remarked with black tapes indicating it is a hot wire. The neutral wire should be in the bundle of white wires in the wire nut in the box.

Here is the instruction sheet:


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## HopelessDiyer

Thanks for the info. I'll check it later on today.


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## kok328

Chances are that your looking at a "switch leg" inside the box and someone neglected to phase the white wire with black tape.
Thus you have no neutral in the box.


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## nealtw

HopelessDiyer said:


> Thanks for the info. I'll check it later on today.



We can see where the black wire comes from , where does the white wire come from?


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## afjes_2016

Take another picture of the box and wires but pull the wires out a bit more so we can count how many cables there are and where exactly each wire is going. You have two switched there. What do those switches control. Tell use which switch controls what. Also take pictures of the back of both switches. I can see by the way they were wired that the person did not have experience. 

kok328: The white he is referring to is a jumper from one switch to the other sending power over to the other switch. There is a bundle of whites in the back and those are probably the neutrals. I do not see that he has a switch loop/leg.


NOTE: The white wire goes to "wh" on switch (bundle of white wires). The black wire going to the fan goes to "rd"(load) on the switch. the hot goes to the screw "bk". You will need a jumper for the white neutral. The present wire going from one switch to the next is a jumper to feed power from one switch to the next. It is not the neutral wire. It should be marked with black tape as being a hot wire.


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## nealtw

afjes_2016 said:


> Take another picture of the box and wires but pull the wires out a bit more so we can count how many cables there are and where exactly each wire is going. You have two switched there. What do those switches control.
> 
> kok328: The white he is referring to is a jumper from one switch to the other sending power over to the other switch. There is a bundle of whites in the back and those are probably the neutrals. I do not see that he has a switch loop/leg.



If it is a switch leg would it be against the rules to use the neutral in the box anyway?


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## afjes_2016

nealtw said:


> If it is a switch leg would it be against the rules to use the neutral in the box anyway?



No it would be fine. As long as there is power in the box which there seems to be. The neutral would go to the wh, the hot to the bk and the wire going back up to the fan to "rd".

but i do not see that it is a switch leg

second thought. if you are sharing a neutral normally it is not a good idea if it is on a different circuit so you don't overload the neutral. but from what i see it seems to be on the same circuit so no.


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## HopelessDiyer

Alright,  thanks for your help guys.   The white wire was definitely hot (fixed it) ,  added a white wire from the connection in back and added a ground too.   Everything works great,  thanks again!


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## nealtw

Success is always an option.:thbup:


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## afjes_2016

Glad you got it.


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