How to separate light and fan


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Old 09-16-18, 01:10 PM
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How to separate light and fan

I have a 1989 built home where all the bathrooms have one set of wiring going from the fan to the light to the switch.

How do I wire it up so I can use a dual switch and control each independently?
which gauge should I use?
Can I run it through the existing EMT? I am in IL which requires EMT for residential electrical.

Thanks
 
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Old 09-16-18, 01:25 PM
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You would need to add a switched hot from the switch to whatever item you want independent control.of. Use the same gauge as already installed. The old switched hot would be removed.
 
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Old 09-16-18, 01:33 PM
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The old switched hot would be removed.
Why would that be ? You'd need two switched hots now.
 
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Old 09-16-18, 03:00 PM
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You need to run another 2-conductor wire (black, white, gnd) from the switch to the fan/light. Or, you could replace the entire run from the switch to the fan/light with a 3-conductor wire (black, red, white, gnd) and use black for one load and red for the other.

And personally, I don't trust other people's wiring, so I would check the breaker that controls the current fan/light and make the wire match that. 15A breaker = 14 gauge wire, 20A breaker = 12 g wire
 
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Old 09-16-18, 04:33 PM
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Need to read the posts. This is a conduit system.
 
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Old 09-16-18, 04:51 PM
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Having EMT makes things much easier.
Just run one more wire. You will need RED 14 AWG THHN assuming it is 15A circuit (which most residential lighting circuits are).

You will need a wire fishing tape, but if you don't have one, just use one of the existing wire and a pull cable and tape 2 wires to it and pull.

Use double switch if existing junction box is a single gang box.
 
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Old 09-16-18, 07:20 PM
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The new switched not does not need to be red, but it would help to keep it separate from the existing switch wiring.

The existing would be removed since it would be replaced by the new switched hot.

You might be able to push the new wire without fishing it in.
 
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Old 09-16-18, 07:45 PM
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I'm still not following. How can you remove the existing switch line and add one new switch line in ?
Aren't two switched lines needed here ?
 
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Old 09-16-18, 08:18 PM
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The existing switched hot goes from Sw to light to fan. The switched hot between the light and fan will be replaced by one from the switch to the fan bypassing the light.
 
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Old 09-30-18, 03:41 PM
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Guys thanks for the help. I can keep the neutral for the light and fan together? or do i need to add another white neutral wire so each device has a switched hot and neutral going to the switch box?
I just add the new red switched hot from the fan to the switch box.

top button = (light blue) switched hot from light on wall.
bottom button = (new red) switched hot from fan.

That will work right?
 

Last edited by enrststavro1; 09-30-18 at 03:59 PM.
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Old 09-30-18, 04:35 PM
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Neutrals can be shared. You only need to run one new piece of wire for the new switch.
 
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Old 10-01-18, 02:00 AM
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All, thanks for the help. I got all 3 bathrooms completed and working properly.
 
 

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