Installing new fan and junction box using existing switch housing

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Old 08-31-12, 04:32 PM
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Installing new fan and junction box using existing switch housing

Hi all. I'm about to install a new fan in my master bedroom and am a bit unsure as to how to most appropriately wire into my existing infrastructure. I will be installing a new junction box between the ceiling joists as there is no current fixture in the ceiling. There is one wall switch in the bedroom with room for another switch. The existing switch in the box controls the outlets along the wall of the bedroom.

Inside of the switch box there is a switch with two wires going into it. One is red (or a brownish color, not sure) and one is black. They both run from one side of the switch up into conduit in the wall. To my knowledge this is a single pole switch that controls all outlets.

I believe that I have other hot power sources up in the attic that I could potentially draw from for the fan. How do I wire from the fan into power and down to the new switch? The fan also has a light fixture and I'm hoping to wire that to a dual fan/light dimmer in the switch box.

Thanks in advance!
 
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Old 08-31-12, 05:48 PM
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You mention conduit. Are you in Chicago? If so are you allowed to use non-metallic cable (AKA Romex)? Do you you want the receptacles to all be always on? If so we may be able to do this by rewiring the first receptacle controlled by the switch.
 
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Old 08-31-12, 09:19 PM
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I will be installing a new junction box between the ceiling joists as there is no current fixture in the ceiling.
Are you talking about a new fan-rated ceiling box?

Inside of the switch box there is a switch with two wires going into it. One is red (or a brownish color, not sure) and one is black. They both run from one side of the switch up into conduit in the wall.
Are those the only two wires in the box?
 
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Old 09-01-12, 06:28 AM
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If this is truly conduit it would be easy to pull a neutral up to the switchbox. Do you really have a pipe or conduit connecting your boxes?

Please fill in your location profile.
 
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Old 09-01-12, 07:42 AM
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Alright, I'll try to consolidate responses. I finalized measuring the location of the fan this morning and next step is to head into the attic.

@ray - Not in Chicago, suburbs...Kane county and I'm told that conduit is required in our township. No, the receptacles are currently wired such that one plug is always on and one is switched. I'd like to keep this behavior for floor lamps.

@Nashkat - Yes, I'm installing a fan rated ceiling box. Yes, there are only two wires in the switch box as noted in my original post...nothing more.

@Pcboss - I have conduit connecting the switchbox to (presumably) the receptacles along the wall. Unfortunately the conduit doesn't seem to go up into the attic so my only accessibility to this is through the receptacles along the wall. Location profile updated.
 
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Old 09-01-12, 08:35 AM
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You will need to drill a hole in the top plate from the attic and install a conduit from the switch box to the fan box. It would be easier if your county allows a metallic cable like MC.

You will need to install a white conductor of the proper gauge from the receptacle up to the switch box and continue it to the fan location.

If you want independent control of the fan and light you will run two hots to the fan box. Wrap one with a colored tape like red or run a different color to identify the function, but not white or green.
 

Last edited by pcboss; 09-01-12 at 03:47 PM. Reason: clarification about taping hots
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Old 09-01-12, 10:32 AM
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Great, thanks pcboss. A couple of clarifying questions...

Where will I get the white conductor? I assume this is the hot power source. It sounds like there should be one in the receptacle that I can just extend back to the switch box. Is that right?

From there it sounds like I should split the white into two lines that go up to the fan/light unit in the attic. I think I'm good there. My question is how I hook up to the switch? Does the white conductor go into the switch itself? If not, couldn't I just pull a white line from something in the attic (I've got an attic fan and a small incandescent light fixture that are powered) instead of going all the way from the receptacle in the room?
 
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Old 09-01-12, 11:51 AM
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The white is the neutral and should not connect to the switch. A neutral will connect to the silver side of the receptacle. You would buy enough white to go from the ceiling box and down to the receptacle.

You cannot grab a nearby white. All conductors of the circuit need to be run together to avoid heating.
 
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Old 09-01-12, 11:54 AM
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Where will I get the white conductor? I assume this is the hot power source.
No, this is your neutral that goes to the fan. Your hot is one of the two wires going to the switch. You can determine that with a multimeter or test light (but not a non-contact tester).

Since you want both the receptacle and fan switched you are going to have to install a duplex switch for the fan in addition to the existing switch or a fan switch
 

Last edited by ray2047; 09-02-12 at 03:27 PM.
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Old 09-01-12, 12:13 PM
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Where will I get the white conductor?
Small rolls of single-conductor wire can be bought at HD and other big box stores, and possibly at your local hardware store. You need 12AWG wire if the circuit is protected by a 20A circuit breaker, and 14AWG wire if the breaker is a 15A.

I assume this is the hot power source.
No. The white conductor will be the grounded conductor, or neutral. That is what you don't have in the switch box now and will need at the fan. Right now you have ungrounded, unswitched power in from the receptacle and ungrounded, switched power back out to the receptacle. IOW, two hot wires, one unswitched and the other switch-controlled.

It sounds like there should be one in the receptacle that I can just extend back to the switch box.
Yes, the receptacle requires a neutral, so there is one there.

From there it sounds like I should split the white into two lines that go up to the fan/light unit in the attic... Does the white conductor go into the switch itself?
No. The white wire is the neutral and should never be switch-controlled. In the switch box, you will need to remove the unswitched feed from the switch, splice it to two short pigtails, and connect one of the pigtails to each switch.

couldn't I just pull a white line from something in the attic,,, instead of going all the way from the receptacle in the room?
No. You cannot use the neutral from a different circuit to supply a load on this circuit, and all of the wiring for a load, and a circuit, must be in the same raceway (conduit).

My question is how I hook up to the switch?
In addition to the pigtails to connect the switches to the unswitched, ungrounded power,
Originally Posted by pcboss
If you want independent control of the fan and light you will run two hots to the fan box. Wrap one with a colored tape like red or run a different color, but not white or green.
You would ideally pull one black and one red wire to the fan box, together with the white wire. To avoid buying a third spool of wire, you can pull both of the switch legs in the same color and use the tape to on one to tell them apart. If you want the fan to stay on while the switch controls the light, you also pull black, red and white. If you want the switch to turn the fan and light on and off together, you can pull one hot wire - black or red - and the neutral.

Tech note: You should leavbe a decent-sized loop of the neutral wire in the switch box. It's code-required and it will facilitate supplying a neutral in the future to a device that has a light, or otherwise needs a neutral.

I took awhile to type my reply, and now I'm hearing an echo! I think you'll find all of the replies in agreement, with some overlap and some unique advice in each.
 

Last edited by Nashkat1; 09-01-12 at 02:07 PM. Reason: corrections
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Old 09-01-12, 12:35 PM
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I'm about to install a new fan in my master bedroom and am a bit unsure as to how to most appropriately wire into my existing infrastructure.
There's a very valuable but inexpensive resource called Wiring Simplified, that explains not only the way to install and connect the components of a residential electrical system, but the reasons behind the methods. It's often available in the electrical aisle at big box home improvement stores.
 
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Old 09-01-12, 03:43 PM
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In post #6 I only meant to use tape to identify between the two hots for their function. Any acceptable color or colors could be used to use as a ungrounded or hot conductor. You could pull two blacks or a black and a red etc. It just helps to keep things straight between the fan motor and the light.
 
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Old 09-02-12, 05:06 AM
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Alright, let me take a stab here based on all the great feedback/info...

I'll pull a white (common) wire from the nearest recetacle back to the switch box where that receptacle is currently controlled (also where my new switches will go). I'll run that white (common) wire up the conduit to the attic and over to my fan/light fixture.

I'll split the existing black (hot) wire that is already in the switch box and wire it into the hot side of all three switches (I'm planning to use a combo light/fan dimmer as the second switch and will leave the current receptacle switch) in the switch box.

I'll run the switched (hot) output of the fan/light switches up through the conduit and into my fan/light fixture.

My only remaining question is around ground. I understand that there will be a ground wire on the fan/light fixture and will hook that up to the box I've installed in the attick to hang the fan. The flex conduit that I purchased has three wire elements...white, black and green. Since I don't have a ground wire in the switch box in the room, can I just use that green wire to run the second switched (hot) output up to the fan/light?

I feel like I'm almost there (and have learned a lot, thanks)!
 
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Old 09-02-12, 06:42 AM
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I feel like I'm almost there (and have learned a lot, thanks)!
You are almost there. Just a few points for clarity:

I'll pull a white (common) wire from the nearest recetacle back to the switch box where that receptacle is currently controlled (also where my new switches will go). I'll run that white (common) wire up the conduit to the attic and over to my fan/light fixture.
There is no "common" in an AC electrical system. The white wire will be the grounded conductor, or "neutral." In order to run it from the switch box to the fan-rated ceiling box, as an individual conductor, you will need to install a continuous empty conduit between the two boxes.

I'll split the existing black (hot) wire that is already in the switch box and wire it into the hot side of all three switches (I'm planning to use a combo light/fan dimmer as the second switch and will leave the current receptacle switch) in the switch box.
While it is reasonable to assume that the black wire in the switch box is carrying the unswitched power from the receptacle, we don't yet know that. That can be determined by testing with a meter or by carefully observing how the red and black wires are connected in the receptacle box. You will only need two pigtails - your combo fan/light dimmer switch will have one terminal for incoming, unswitched power.

I'll run the switched (hot) output of the fan/light switches up through the conduit and into my fan/light fixture.
Right.

My only remaining question is around ground. I understand that there will be a ground wire on the fan/light fixture and will hook that up to the box I've installed in the attick to hang the fan. The flex conduit that I purchased has three wire elements...white, black and green. Since I don't have a ground wire in the switch box in the room, can I just use that green wire to run the second switched (hot) output up to the fan/light?
Here's a problem. What you've described isn't conduit. It's cable, specifically Type MC, and you can't pull any wires through it. In order to pull wires, you need an empty conduit, which may be either flexible or non-flexible.

The cable you purchased doesn't have three wire elements, it has three wires. It is a two-conductor cable because only two of the three wires, the black and the white, may be used as current-carrying conductors. The green wire may only be used for ground.

If you want to use Type MC cable instead of conduit between the switch and the fan, you need three-conductor cable. That cable will have two hot wires - a black and a red - one neutral - white - and a ground - green. The black and the red will connect the switched outputs from your combo switch to the fan motor and the light. The white will connect the white wire from the receptacle box to the white wire in the fan. The green wire will be bonded to the metal switch box and the metal ceiling box, and will also be connected to any and all green or bare wires that come with the fan.
 
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Old 09-02-12, 07:17 AM
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Alright, think I've got it. Time for a trip back to the hardware store and then I'll start wiring. Now if anyone has suggestions on how to determine where I need to drill my hole down from the attic so I can tie directly into the switch box below I'm all ears! Seems like that may the most difficult part remaining.
 
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Old 09-02-12, 07:52 AM
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suggestions on how to determine where I need to drill my hole down from the attic so I can tie directly into the switch box
Draw an imaginary line in the room from the switch box to the ceiling. Drill a 1/8" hole into the attic and insert a stiff wire such as a piece of wire coat hanger then go in the attic and look for where it is sticking up. Use that as your guide. Normally you can see the stud plate between rooms. Drill your marker hole out about 2" from the wall to miss any boards that may have been added to the stud plate to fasten the Sheetrock to.
 

Last edited by ray2047; 09-02-12 at 03:29 PM.
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Old 09-02-12, 07:53 AM
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Time for a trip back to the hardware store and then I'll start wiring.
Remember to get all the fittings and straps you need for your new conduit or cable.

Now if anyone has suggestions on how to determine where I need to drill my hole down from the attic so I can tie directly into the switch box below I'm all ears! Seems like that may the most difficult part remaining.
It may be. I often remove the existing box and drill up, but you need a special drill bit to do that.

In the attic, the top plate of the wall will be visible, although you might have to move some insulation to see it. If you measure from the nearest wall to the center of the switch box, or the center of the location for the new switch, and add the thickness of the wall facing on the wall you're measuring from, then you should be able to find the intersection of the framing for those two walls in the attic and measure along the plate you need to drill into to find the right spot.
 
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Old 09-02-12, 08:00 AM
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Ray, I like your trick with the marker wire better than measuring. And the OP said he was installing a combination fan and light switch.
 
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Old 09-02-12, 08:23 AM
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I started the work of getting the white (neutral) wire routed up from a receptacle. I've been able to run a fish tape down from the attic into the closest receptacle and will split off the white (neutral) wire back up the conduit.

My new question is this. Do I have to run a seperate conduit down to the switch box? Can't I just run the two new switched wires up into the attic using the existing conduit and into a junction box? From the junction box I would run the existing receptacle switch wires down the conduit they're currently in and just split off the two new switched wires plus the new white (neutral) wire over to the fan/light fixture? This would save me the step of running a new piece of conduit through the top plate and to the box. My fear is that the existing conduit is only supposed to have the receptacle switched wires and the fan/light is supposed to have its own. If that's the case can someone comment as to why they can't all go in the same conduit?
 
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Old 09-02-12, 08:32 AM
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If you have the existing switch wires in this attic junction box and have the new neutral there then you can make your connections there. You will need to run a third wire any color but white, gray, green, or green/yellow to the switch box.
 

Last edited by ray2047; 09-02-12 at 03:30 PM.
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Old 09-02-12, 08:53 AM
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So does that mean that my current thoughts on how to wire this will not accomodate for the switched receptacle outlets in the room? This is a hard requirement for my application. I need to be able to continue to switch the receptacles in the bedroom and operate the fan and light fixture independently from the receptacles. Do I need to do something with the white (neutral) wire to make this happen or am I alright doing what I'm doing to meet this need.

While I'm asking, the extra wire I have is 14 gauge versus the 11 gauge that is currently in the wall. I checked the breaker and it's only 15 amp so I assume it's okay to mix these gauges as the weakes link (14 gauge) is still satisfactory for the application. Please let me know if I'm mistaken.
 
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Old 09-02-12, 10:02 AM
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Yes, you can keep the switched receptacles and control your light and fan from your new switch. You should not need to add either conduit or cable from the switch box to the attic.

This:
I've been able to run a fish tape down from the attic into the closest receptacle
changes the best way to do it. I will add more soon.
 
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Old 09-02-12, 10:04 AM
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So does that mean that my current thoughts on how to wire this will not accomodate for the switched receptacle outlets in the room?
I have revised all my posts. Thanks to Nash I re-read your first post and though you didn't say you have a 2-gang box your wording indicates you do so I was off base on my answers.

While I'm asking, the extra wire I have is 14 gauge versus the 11 gauge that is currently in the wall.
No such animal as 11 gauge. If the breaker is 20 amps use #12. If it is 15 amp use #14.
 

Last edited by ray2047; 09-02-12 at 03:34 PM.
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Old 09-02-12, 10:58 AM
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Point of clarification...I intend to leave the existing switch in place to continue independently controlling the receptacles along the wall. I'll be adding a new (dual) switch that controls the fan/light. That means there will be two switch housings in the switch box total.

So my question remains on if I can put the switchable lines for both the receptacles and the fan/light in the same conduit line up to the attic and then route it from there through a junction box to the receptacles and fan/light individually. This would prevent me from having to take the white (neutral) line down into the switch box just to bring it back up to the attic. I'd simply bring it up to the junction box in the attic and route it to the fan along with the switched lines.
 
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Old 09-02-12, 11:43 AM
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While I'm asking, the extra wire I have is 14 gauge versus the 11 gauge that is currently in the wall. I checked the breaker and it's only 15 amp so I assume it's okay to mix these gauges as the weakes link (14 gauge) is still satisfactory for the application. Please let me know if I'm mistaken.
To answer this question first, yes, 14 gauge wire is the appropriate size for a 15 amp circuit.

OK. I don't know why I didn't think of a conduit between the receptacle box and a J-box in the attic. But there it is.

With the power off at the breaker, use your fish tape to pull three individual wires between the 2-gang switch box and the receptacle box. Pull two hots and a neutral. These should ideally be a black, red and white, but can be two blacks or two reds and one white. If you pull the two hots in the same color, mark one of them with tape, as pcboss suggested earlier, so you can tell which is which. leave a loop in the new hot wires behind the receptacle box.

Pull the two hots up to the box in the attic.

In the switch box, pigtail the existing hot wire from the receptacle box and connect it to both switches. Ground both switches to the metal box. If you pulled a red and a black, connect the red wire to the e new switch and the black wire to the fan output. If your new switch takes a neutral, connect the new white wire there. If it doesn't take a neutral, use a small wire nut to cap the white wire and fold it into the box for future use. Mount the switches.

In the receptacle box, take the white wire off the receptacle, splice that to the new white wire and a pigtail, and connect the pigtail to the receptacle where the white wire was connected before. Fold everything into the receptacle box and re-mount the receptacle.

In the J-box in the attic , I'll assume you're using 14-3/G MC cable. If you're using metal conduit with individual conductors, ignore the instructions for the ground wire.

Strip about 8" of the jacket off the cable and connect it into the box. Splice the green ground wire to the other grounds in the box. Splice the white neutral wire to the white neutral going down to the receptacle. Splice the red wire to the wire you pulled from the light output on the new switch. Splice the black wire to the wire you pulled from the fan output on the switch. Make sure the wire nuts are tight and close the J-box.

At the ceiling box, strip and connect the cable. Connect the black wire to the fan motor feed, the red wire to the fan light feed, the white wire to the fan white wire, and the green wire to the box and to all green or bare wires that came with the fan.

Mount the fan and turn the power back on. Cover the switches and the receptacle if you didn't already.
 
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Old 09-02-12, 03:36 PM
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Apologies for my not realizing you had a 2-gang switch box. I have revised some of my previous comments.
 
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