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  1. #1
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    Apr 2012
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    Default Bath Fan/Light combo switch + recepticle, 2-Gang

    I have a scenario with multiple questions, so I'm hoping someone can give me advice. First off, let me state that my house is 119 years old and there is some active Knob and Tube (K&T) circuits left on the 2nd floor/attic.
    My idea is to add a bathroom fan (without a light, just a fan) to the 2nd floor bathroom where there is no exhaust fan currently. As of right now, I have two wall scones for lights in the bathroom that are powered by K&T wiring from a switch as well as a GFCI outlet in a 2-gang box. What I want to do is:
    1. Put in a combo switch in existing gang-box (one switch for scones, one for fan) & leave in place the outlet.
    2.Run a new, separate NM power feed from a nearby bedroom outlet with NM cable to the 2-gang box to power the GFCI & newly installed fan separate.
    3.Use the existing K&T feed to power 2nd switch which will power the scones only.
    Currently, the existing feed is K&T that feeds both the GFCI and lights, so I have two blacks and one white wire in my Gang box. After adding the combo switch, the 2nd NM power feed, and the NM load wires going back to the Fan, I fear I might have too many wires in a 2-gang box as well as possibly a single white neutral K&T wire floating.
    Any Ideas or advice (other than calling an electrician)? Can I have two circuits in one gang-box? I would like to have the fan and GFCI on its own, new, NM circuit to reduce the load on the existing K&T. I would like to avoid powering the new fan off of the K&T circuit. I also need to leave the K&T wiring to the lights in place if possible, being it would be extremely difficult to replace the wiring in the walls. Thanks!

  2. #2
    Join Date
    Jan 2011
    Location
    Columbiana, Alabama
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    Default Re: Bath Fan/Light combo switch + recepticle, 2-Gang

    Quote Originally Posted by BrianH1237 View Post
    I have a scenario with multiple questions, so I'm hoping someone can give me advice. First off, let me state that my house is 119 years old and there is some active Knob and Tube (K&T) circuits left on the 2nd floor/attic.
    My idea is to add a bathroom fan (without a light, just a fan) to the 2nd floor bathroom where there is no exhaust fan currently. As of right now, I have two wall scones for lights in the bathroom that are powered by K&T wiring from a switch as well as a GFCI outlet in a 2-gang box. What I want to do is:
    1. Put in a combo switch in existing gang-box (one switch for scones, one for fan) & leave in place the outlet.
    2.Run a new, separate NM power feed from a nearby bedroom outlet with NM cable to the 2-gang box to power the GFCI & newly installed fan separate.
    3.Use the existing K&T feed to power 2nd switch which will power the scones only.


    Currently, the existing feed is K&T that feeds both the GFCI and lights, so I have two blacks and one white wire in my Gang box. After adding the combo switch, the 2nd NM power feed, and the NM load wires going back to the Fan, I fear I might have too many wires in a 2-gang box as well as possibly a single white neutral K&T wire floating.
    Any Ideas or advice (other than calling an electrician)? Can I have two circuits in one gang-box? I would like to have the fan and GFCI on its own, new, NM circuit to reduce the load on the existing K&T. I would like to avoid powering the new fan off of the K&T circuit. I also need to leave the K&T wiring to the lights in place if possible, being it would be extremely difficult to replace the wiring in the walls. Thanks!
    Brian, it sounds like a great house, would love to see pictures.

    Yes it's legal to have two circuits in a box.

    Combo switches mean the box size stays the same but more wire is added, not good, especially if the other slot has a GFCI.

    I would replace the two gang box with at least the biggest 2 gang I could find or a huge 3 or 4 gang (blind off the unused spaces, and not do a combo. Also, try to remove the K & T power and just use the new romex feed.
    Good Luck from Columbiana, Alabama
    Maurice Turgeon, Hidden Content

  3. #3
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    Apr 2012
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    Default Re: Bath Fan/Light combo switch + recepticle, 2-Gang

    Thanks for the reply Maurice!
    I have thought about this all day, and I think my best, safest and legal bet would be to put in a old work 3 gang box or cut out the side of the original gang box and in another single gang box, removing one side of that, and screw the two together (making a 3 gang box) to have enough space to accommodate the additional wires.
    I would like to replace the current K&T line feed in this box, but the vanity lights are on a circuit along with ALL of the other lights on the 2nd floor...so I'm not sure if I break that circuit if all my other lights would still work or not...It's kind of hard for me to explain, but I basically want to accomplish having the GFCI outlet and FAN in the Bathroom on the romex circuit from the nearby bed room and then leave the vanity lights on the original K&T circuit (using two switches), that way I wont have to remove any K&T wiring. I am not afraid of the existing K&T, it has function well for a century, I just don't want to over load it with the new fan and outlet, thus the 2nd circuit in the same box. Plus removing the existing K&T would involve extensive re-work. To my knowledge, existing K&T is within code as long as it's not modified in anyway, so if I can get by with powering the new fan and GFCI from the nearby romex line feed without modifying the connection to the existing vanity lights, I think I should be okay, I just seem to need more space in the Gang box. Thanks again!

  4. #4
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    Jan 2011
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    Columbiana, Alabama
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    Default Re: Bath Fan/Light combo switch + recepticle, 2-Gang

    Quote Originally Posted by BrianH1237 View Post
    Thanks for the reply Maurice!
    I have thought about this all day, and I think my best, safest and legal bet would be to put in a old work 3 gang box or cut out the side of the original gang box and in another single gang box, removing one side of that, and screw the two together (making a 3 gang box) to have enough space to accommodate the additional wires.
    I would like to replace the current K&T line feed in this box, but the vanity lights are on a circuit along with ALL of the other lights on the 2nd floor...so I'm not sure if I break that circuit if all my other lights would still work or not...It's kind of hard for me to explain, but I basically want to accomplish having the GFCI outlet and FAN in the Bathroom on the romex circuit from the nearby bed room and then leave the vanity lights on the original K&T circuit (using two switches), that way I wont have to remove any K&T wiring. I am not afraid of the existing K&T, it has function well for a century, I just don't want to over load it with the new fan and outlet, thus the 2nd circuit in the same box. Plus removing the existing K&T would involve extensive re-work. To my knowledge, existing K&T is within code as long as it's not modified in anyway, so if I can get by with powering the new fan and GFCI from the nearby romex line feed without modifying the connection to the existing vanity lights, I think I should be okay, I just seem to need more space in the Gang box. Thanks again!
    Brian, I understand not wanting to disrupt the K&T so, the 3G old work box seems like the best fix.

    Don't cut on a UL listed box!

    Just for grins, you might open the K&T circuit and see what's on it. You might want to change your plans, based on the results.
    Good Luck from Columbiana, Alabama
    Maurice Turgeon, Hidden Content

  5. #5
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    Apr 2012
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    Default Re: Bath Fan/Light combo switch + recepticle, 2-Gang

    By "cut-out" I mean cut out another space in the wall to add another box. The existing 2-gang box is a metal, gangable box. So I went to the hardware store, got the same size gangable box, took the two gang box out, added the additional gang, so now I have a 3 gang old-work metal box in the wall. Now I am ready to add in the GFCI/Fan circuit and switch and then have the 2nd switch (off the K&T) control the vanity lights. I assume that when I run the circuit from the romex feed to the GFCI/Fan, I will need to ground the metal box from the ground wire in the romex? The original 2-gang box is not grounded at all. My fan switch will also be off the load side of the GFCI, so my fan will be protect as well, which is good. I'd like to power my vanity lights off the new romex feed, but I don't want to leave an old, hot K&T live feed inside of my wall with no connection.

  6. #6
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    Columbiana, Alabama
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    Default Re: Bath Fan/Light combo switch + recepticle, 2-Gang

    Quote Originally Posted by BrianH1237 View Post
    By "cut-out" I mean cut out another space in the wall to add another box. The existing 2-gang box is a metal, gangable box. So I went to the hardware store, got the same size gangable box, took the two gang box out, added the additional gang, so now I have a 3 gang old-work metal box in the wall. Now I am ready to add in the GFCI/Fan circuit and switch and then have the 2nd switch (off the K&T) control the vanity lights. I assume that when I run the circuit from the romex feed to the GFCI/Fan, I will need to ground the metal box from the ground wire in the romex? The original 2-gang box is not grounded at all. My fan switch will also be off the load side of the GFCI, so my fan will be protect as well, which is good. I'd like to power my vanity lights off the new romex feed, but I don't want to leave an old, hot K&T live feed inside of my wall with no connection.
    OK Brian, that sounds like a great way to get a bigger box w/o having to completely remove the old one. Yes, the new romex ground should be connected to the box and some places also require it be tied to the device ground. If I were you I would just wirenut the K&T off in the box, if I could not de-energize it at the source. As you say, it should not be just placed in the wall "hot".

    Let us know how the project turns out.
    Good Luck from Columbiana, Alabama
    Maurice Turgeon, Hidden Content

  7. #7
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    Default Re: Bath Fan/Light combo switch + recepticle, 2-Gang

    Thanks Maurice! One last question...
    Is it okay to have the GFCI outlet and Fan in the bathroom coming off the load from the nearby bedroom outlet? I read somewhere that Bathrooms need to be on their own circuit...The circuit from the bedroom is 12/2 NM with ground and is on a 20 amp breaker with 5 total 15 amp recepticles on the circuit already. Is all of this okay and safe? I just want to be sure I am following the rules. I will be sure to ground the metal box as well as the devices. Also, is there any recommendation or requirement as to notifying future owners/inspectors that there are two circuits in the same box? Thanks for all your input!
    -Brian

  8. #8
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    Columbiana, Alabama
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    Default Re: Bath Fan/Light combo switch + recepticle, 2-Gang

    Quote Originally Posted by BrianH1237 View Post
    Thanks Maurice! One last question...
    Is it okay to have the GFCI outlet and Fan in the bathroom coming off the load from the nearby bedroom outlet? I read somewhere that Bathrooms need to be on their own circuit...The circuit from the bedroom is 12/2 NM with ground and is on a 20 amp breaker with 5 total 15 amp recepticles on the circuit already. Is all of this okay and safe? I just want to be sure I am following the rules. I will be sure to ground the metal box as well as the devices. Also, is there any recommendation or requirement as to notifying future owners/inspectors that there are two circuits in the same box? Thanks for all your input!
    -Brian
    Brian, the Code allows everything in a bath to be on the one 20A circuit, if that circuit only serves that one bath.

    If the circuit serves a second bath, only the GFCI receptacles can be on it.

    Code allows items other than the receptacle to be on either the load or line side of the GFCI. However, some items such as shower lights and fans must be on the load side, if stated in the manufacturers installation instructions. I place everything in a bath on the load side. Others argue if the GFCI trips the room goes dark and that too is dangerous.

    In residential work, no notice is required to be posted that there is more than one source of power. But, it's a great idea to make such a note and place it in the box, with the breaker numbers. Good idea for a Code change!
    Good Luck from Columbiana, Alabama
    Maurice Turgeon, Hidden Content

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