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Thread: switch leg ?

  1. #1
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    Default switch leg ?

    When wiring a switch leg, which method do you prefer?
    1 Connect the all black wires together, and white of switch to fixture, or
    2 connect white from switch to blacks, and black of switch to fixture
    Note: both reID the white switch leg wire

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  2. #2
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    Default Re: switch leg ?

    Quote Originally Posted by Rick Cantrell View Post
    When wiring a switch leg, which method do you prefer?
    1 Connect the all black wires together, and white of switch to fixture, or
    2 connect white from switch to blacks, and black of switch to fixture
    Note: both reID the white switch leg wire
    This is NOT allowed: "1 Connect the all black wires together, and white of switch to fixture"

    - 200.7 Use of Insulation of a White or Gray Color or with Three Continuous White Stripes.
    - - (C) Circuits of 50 Volts or More. The use of insulation that is white or gray or that has three continuous white stripes for other than a grounded conductor for circuits of 50 volts or more shall be permitted only as in (1) through (3).
    - - - (1) If part of a cable assembly and where the insulation is permanently reidentified to indicate its use as an ungrounded conductor, by painting or other effective means at its termination, and at each location where the conductor is visible and accessible. Identification shall encircle the insulation and shall be a color other than white, gray, or green.
    - - - (2) Where a cable assembly contains an insulated conductor for single-pole, 3-way or 4-way switch loops and the conductor with white or gray insulation or a marking of three continuous white stripes is used for the supply to the switch but not as a return conductor from the switch to the switched outlet. In these applications, the conductor with white or gray insulation or with three continuous white stripes shall be permanently reidentified to indicate its use by painting or other effective means at its terminations and at each location where the conductor is visible and accessible.
    - - - (3) Where a flexible cord, having one conductor identified by a white or gray outer finish or three continuous white stripes or by any other means permitted by 400.22, is used for connecting an appliance or equipment permitted by 400.7. This shall apply to flexible cords connected to outlets whether or not the outlet is supplied by a circuit that has a grounded conductor.
    - - - - FPN: The color gray may have been used in the past as an ungrounded conductor. Care should be taken when working on existing systems.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
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  3. #3
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    Default Re: switch leg ?

    Jerry
    I really really hate to disagree with you on electrical.
    I prefer 2#, but I don 't think #1 is not allowed.

    I read that code different than you.

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

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    Default Re: switch leg ?

    Some houses have what is called a "switch loop" and may have been allowed at one time but is dangerous. With this crappy method, the hot goes to the fixture first then a loop is sent to the switch. Many DIY types would turn off the switch to install a ceiling fan and get shocked while standing on the ladder.

    Switch loops can not be found during a regular home inspection.

    Bruce King, B.A. King Home Inspections, LLC
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    Certified Master Inspector, Independent Inspectorwww.IndependentInspectors.org

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    Default Re: switch leg ?

    I'm no code guru but as far as I know both methods are common and accepted. Meaning power to the light than running a loop or running through the switch with the hot. Calling one a "crappy" method is totally an opinion.

    As for how to run a switch loop - white is junctioned with the hot at the origination of the switch loop so the returning power is black/hot.

    I'm guessing the code will back this up.


  6. #6
    David Bell's Avatar
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    Default Re: switch leg ?

    When wiring a switch loop you should wrap black tape on both ends of the white wire and lable it a switch loop.


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    Default Re: switch leg ?

    Quote Originally Posted by Bruce King View Post
    Some houses have what is called a "switch loop" and may have been allowed at one time but is dangerous. With this crappy method, the hot goes to the fixture first then a loop is sent to the switch. Many DIY types would turn off the switch to install a ceiling fan and get shocked while standing on the ladder.

    Switch loops can not be found during a regular home inspection.

    This is still allowed as per the NEC

    Crappy install ? Why ? ( Your opinion ) perfectly fine provide installed correctly- white reidentified and used as a supply to the switch as per the
    nec.

    I would think that they would be evident by removing the switch plate and looking into the box at the conductors attached to the switch

    Diy'er getting shocked ? If they don't know /understand what they are doing they should hire a professional. Whats the old phrase -
    when you play with fire you will get burned

    Last edited by ken horak; 02-02-2010 at 03:00 PM.

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    Default Re: switch leg ?

    Quote Originally Posted by ken horak View Post
    and used as a return as per the
    nec.

    In looking around the net at various diagrams I see it both ways - white as return and black as return (with white re-identified, of course). I'd always done it with black as return but am happy to admit I'm wrong. Is is specified a certain way or is either okay as long as it's re-indentified?


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    Default Re: switch leg ?

    Quote Originally Posted by Matt Fellman View Post
    In looking around the net at various diagrams I see it both ways - white as return and black as return (with white re-identified, of course). I'd always done it with black as return but am happy to admit I'm wrong. Is is specified a certain way or is either okay as long as it's re-indentified?
    I stand corrected ! My mind was thinking it out correctly but my fingers typed it incorrect. (I really need to proof read better )
    I stated used as the return - It should be used as the supply.
    It can only be used to feed a switch or used as "travellers" in 3 way /4 way switches. The white conductor must be reidentified.
    Jerry Peck poste dthe code article in post #2. NEC article 200.7 (C) (2)

    I corrected my original post - my apologies for the confusion


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    Default Re: switch leg ?

    You will know it's done wrong if an outlet winds up with 2 white wires (remarked or not), which is what the rule intends to prevent. Should the remarking disappear for whatever reason you don't have to guess which white wire is hot.

    You will still see switch legs as a pretty common wiring method. Wiring with a hot supply cable to the switch boxes is usually more expensive both in wire and cost of switch boxes (they have to be larger).

    Some newer switching devices require a neutral and so seeing a 3 or 4 conductor cable in a switchbox with the white being a neutral is becoming more common


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    Default Re: switch leg ?

    IIRC there is a change coming in the 2011 NEC that will require a neutral at each switch box. I guess that will be the end of switch loops.


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    Default Re: switch leg ?

    What would be the logic for requiring a neutral at a switch location ?


  13. #13
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    Default Re: switch leg ?

    Quote Originally Posted by ken horak View Post
    What would be the logic for requiring a neutral at a switch location ?
    I believe it has something to do with more and more switching devices needing a neutral connection or the potential to need on in the future.

    Just one more area of "design" that the code is getting into IMO.

    BTW Ken, are you here or there? I know it is cold here and snowy. Hope it is better there .


  14. #14
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    Default Re: switch leg ?

    Quote Originally Posted by Rick Cantrell View Post
    I don 't think #1 is not allowed.

    I read that code different than you.
    What part make you think that it is "not" "not allowed"?

    "the conductor with white or gray insulation or a marking of three continuous white stripes is used for the supply to the switch but not as a return conductor from the switch to the switched outlet."

    I had even put that in red text - then read the bold text which follow the "but not as" part.

    It is not allowed even AFTER "In these applications, the conductor with white or gray insulation or with three continuous white stripes shall be permanently reidentified " permanently reidentifying it from white.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

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    Default Re: switch leg ?

    i do believe that the NEC is getting dangerously close to " design".
    The code should not be a design manual !

    I was "there" last week - went on Vacation to Las Vegas.
    I'm "Here" now though - (where ever Here is)


  16. #16
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    Default Re: switch leg ?

    Jerry
    Since I have confidence in you, I accept what you say (on many things) is correct, including this. Having accepted that you are correct I read the code again, and again, and again. You are correct.
    As always thank you for your time and efforts

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  17. #17
    Roger Frazee's Avatar
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    Default Re: switch leg ?

    Quote Originally Posted by Bruce King View Post
    Some houses have what is called a "switch loop" and may have been allowed at one time but is dangerous. With this crappy method, the hot goes to the fixture first then a loop is sent to the switch. Many DIY types would turn off the switch to install a ceiling fan and get shocked while standing on the ladder.

    Switch loops can not be found during a regular home inspection.
    Bruce

    You sound as if you would write this up if you found a switch loop. IMO if you went looking for switch loops you would be righting them up to he point your inspections bill would have to include ink costs. These are common common common and no more dangerous that any other design. What I consider dangerous in residential is 2 wire methods of nm with metal boxes and the wife has a passion for metal face/trim plates...
    When you open the switch box using a switch loop and you know what your doing it is instantly obvious to you .. white wire..reidentified or not.. Much safer than opening a box with a multiwire branch circuit and it was wired not using a double pole breaker. Point being the wiring codes were not concerned about John Doe homeowner sticking his fingers somewhere they don't belong.


    Drawing showing a common switch loop is below .... if your mindset is the only way that a light can be wired is power to the switch and then to the light ...you probably should sell your voltage tester .. if you get my meaning.

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  18. #18
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    Default Re: switch leg ?

    Quote Originally Posted by Roger Frazee View Post
    Bruce

    You sound as if you would write this up if you found a switch loop. IMO if you went looking for switch loops you would be righting them up to he point your inspections bill would have to include ink costs. These are common common common and no more dangerous that any other design. What I consider dangerous in residential is 2 wire methods of nm with metal boxes and the wife has a passion for metal face/trim plates...
    When you open the switch box using a switch loop and you know what your doing it is instantly obvious to you .. white wire..reidentified or not.. Much safer than opening a box with a multiwire branch circuit and it was wired not using a double pole breaker. Point being the wiring codes were not concerned about John Doe homeowner sticking his fingers somewhere they don't belong.


    Drawing showing a common switch loop is below .... if your mindset is the only way that a light can be wired is power to the switch and then to the light ...you probably should sell your voltage tester .. if you get my meaning.

    LOL! Glad I could amuse you too but you should have not assumed anything as you did. No, I do not look for switch loops or write them up, what I do on here and other forums is post helpful information for a larger audience than just home inspectors. Homeowners do read these threads and I may have saved a life by posting what I did.

    Bruce King, B.A. King Home Inspections, LLC
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    Certified Master Inspector, Independent Inspectorwww.IndependentInspectors.org

  19. #19
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    Default Re: switch leg ?

    Roger,
    I was struggling a little with why the re-identified white had to be the hot, but as they say a picture is worth a thousand words, thanks for posting the diagram.

    I seen your name in the lower right corner, is this a diagram you created, and if so do you mind if I use it.


  20. #20
    Roger Frazee's Avatar
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    Default Re: switch leg ?

    Quote Originally Posted by Bruce King View Post
    LOL! Glad I could amuse you too but you should have not assumed anything as you did. No, I do not look for switch loops or write them up, what I do on here and other forums is post helpful information for a larger audience than just home inspectors. Homeowners do read these threads and I may have saved a life by posting what I did.
    I didn't assume you wrote switch loops up. I read what you said ... and it sounded like you were saying that they were allowed at one time and are dangerous. I was saying that.. if .. you write them up for being not allowed then your wasting ink....

    Now I agree 100% about educating a larger audience and yep you just may have saved a life.

    Who do you think I was directing the drawing two ....?

    Also what I was saying is .. that if you trust a switch to always turn the power off to a fixture then you might as well toss your voltage tester. Meaning that even though you turned off a switch or a circuit breaker or a disconnect or whatever you better verify that voltage has indeed been removed from that fixture by using a voltage tester.
    The fact that you educated a homeowner to what a switch loop is doesn't change that basic safety rule.

    Last edited by Roger Frazee; 02-03-2010 at 07:51 PM.

  21. #21
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    Default Re: switch leg ?

    Quote Originally Posted by chris mcintyre View Post
    Roger,
    I was struggling a little with why the re-identified white had to be the hot, but as they say a picture is worth a thousand words, thanks for posting the diagram.

    I seen your name in the lower right corner, is this a diagram you created, and if so do you mind if I use it.
    Chris

    You may use any diagram I post here I have no copyrights.

    The specific code we are talking about is 200.7(C)(2) in the 2008 NEC. Jerry pasted it earlier in this thread. White in a cable assembly is the selected color for a grounded conductor and they are not to be switched on the return to the fixture like ungrounded conductors when the white is used in single pole, 3 way and 4 way switch loops. . You can however reidentify a white (that is in a cable assembly like nm-b) as an ungrounded hot wire by coloring it black at each end anywhere else in that switch loop.

    Last edited by Roger Frazee; 02-03-2010 at 07:50 PM.

  22. #22
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    Default Re: switch leg ?

    Quote Originally Posted by Roger Frazee View Post
    The specific code we are talking about is 200.7(C)(2) in the 2008 NEC. Jerry pasted it earlier in this thread. White in a cable assembly is the selected color for a grounded conductor and they are not to be switched on the return to the fixture like ungrounded conductors when the white is used in single pole, 3 way and 4 way switch loops. . You can however reidentify a white (that is in a cable assembly like nm-b) as an ungrounded hot wire by coloring it black at each end anywhere else in that switch loop.
    Got it.


    You may use any diagram I post here I have no copyrights.
    Thanks!


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