Electrical help!

Nathanm

Hello all, and thank you in advance for any help you can provide! Here is the deal I wanted to put a bathroom exhaust fan in and was told I could come off the existing switch to cut the wire, install a junction box, tie the wires all back in adding the wires for the fan. Trouble is the bathroom light stays on with the switch off. Turn the switch on light dims and the fan now runs, switch off fan shuts off light goes bright used black to black white to white where oh where did I go wrong!?

jbfan

Sounds like you cut into a switch leg.
How many wires are in the switch box?

__________________
Yes I am a Pirate, 200 years too late. "Jimmy Buffett"

dmxtothemax

Sounds like the light and fan are now wired in series !
You have made a mistake in your wiring !
If the wires you tapped into,
where part of a switch loop,
That would explain it all !
You will need to reroute your wiring to a point where
there is a neutral available.
Switch loops dont usually have a neutral.
There will be one available at the light.

Nathanm

Thank you for the reply. I just went to check, only two wires in the switch box I'm trying to run from

jbfan

You can not do what you want.
You need to remove the wire you installed and connect the wires you cut back together.
Remove the light fixture and connect the wires to the fan to the same wires the fixture is connected to.
The light and fan will work at the same time.
If you need other options, then you will have to run some new wiring.

__________________
Yes I am a Pirate, 200 years too late. "Jimmy Buffett"

Nathanm

jbfan, thank you for your help I have removed the wire and rewired as it originally was. Will follow your advice and post how I get along, thanks!

k_buz

Is there attic above this?

If you cut the wire, you still have a junction box right? Is that J-Box going to be accessible after this is all said and done?

Nathanm

K_buz, yes attic is above it, yes I can access the j box

hammerlane

so currently this is what you have??

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Nathanm

Indeed that is correct, That was the set up

hammerlane

And now you want to add a switch controlled exhaust fan? Will the switch that controls this new exhaust fan be in the same box as the switch that currently controls the light? Or are you replacing the current switch with a double toggle switch?

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hammerlane

Heres another switch loop set up for the fan. This setup you have to get power into the fan box and then run the switch loop back to the switch for the fan.

As a not I do not show ground wires in the diagram just for ease of drawing.

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hammerlane

Heres a setup where where the power for the exhaust fan is brought into the switch box that houses the switch for the fan.

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Nathanm

So I will have to run another switch I can't tap into the loop behind the light for power and have both fan and light run from the one switch already installed?

kevinp22

you can use the existing switch loop to control the light and fan but you wont be able to control them independently. either both on or both off. even in this case, of course, you will have to run a cable from the light to the fan