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How I want to add a neutral to a switch loop - Is it safe?

How I want to add a neutral to a switch loop - Is it safe?

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  #1  
Old 12-09-15, 05:35 PM
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How I want to add a neutral to a switch loop - Is it safe?

All three functions of my bathroom's fan/light appliance are controlled by unpowered switch loops (No AC source in the switch box). Two of those switch loops are in a single 2-gang box. I would like to reconnect the wires as shown in my diagram so as to get a circuit "neutral" into the box and permit the installation of a timer switch to control the fan. I can't think of a reason why this wouldn't work just fine... and be safe, as well. Waddaya YOU think?
(Sorry for the photo. I didn't know it would be so small until after I saw the post.)

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Last edited by ray2047; 12-09-15 at 05:47 PM. Reason: Enlarge diagram.
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  #2  
Old 12-09-15, 05:40 PM
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Do you have conduit that will allow the other conductor to be installed? You cannot just a another conductor if you have cable. You would need a new cable with all the conductors in it.
 
  #3  
Old 12-09-15, 05:44 PM
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I'm not "adding" a conductor, boss. I'm re-purposing one of the conductors already in the wiring harness.
 
  #4  
Old 12-09-15, 05:49 PM
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I'm thinking what you propose is ok. The boss is the code guru. I bow to his expertise.
If what you proposed is ok.... then the white should be taped or remarked another color to signify it's not a neutral. You showed neutral as brown which is incorrect. Also... you cannot remark a black wire white.

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  #5  
Old 12-09-15, 06:02 PM
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It Might just be your diagram , but the white is the hot feed to the switch in a switch loop.
 
  #6  
Old 12-09-15, 06:03 PM
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There are 2) two wire cables to the two gang box. Instead of using them as switchloops... the wiring would be changed. I explained in my post about the brown.

He has two switches. He needs a hot down, neutral down and two switched hots back up.
 
  #7  
Old 12-09-15, 07:13 PM
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Okay. Pete has managed to make sense of my primitive drawing and has assigned the appropriate and logical (blush) color coding to the rewiring.

In the 2-gang box, I will keep the BLACK conductor in the Shower Light circuit as the black down hot, and I will connect it by a black jumper to also feed the Vent Fan switch.
The WHITE wire in the Shower Light circuit has already been re-colored to black since it already serves as a switched hot up wire.
I will repurpose the WHITE conductor in the Vent Fan circuit to be the new (white) down neutral, and I will reconnect the BLACK conductor in that circuit to be the new (black) switched hot up wire.
All ground wires do now currently serve their assigned ground wire function and will continue to so.
Thanks to everyone for your expertise and input to solving this problem.
 
  #8  
Old 12-10-15, 04:32 AM
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One caveat - this normally needs plastic boxes and NM cable to be code compliant.
 
  #9  
Old 12-10-15, 04:58 AM
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Why only plastic boxes?
Just curious
 
  #10  
Old 12-10-15, 07:43 AM
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Yeah, me too. I'd be interested in the need for a plastic box. Fortunately, that's what is already in place. Here's the final plan for the modification.
Thanks again to all.
 
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  #11  
Old 12-10-15, 07:49 AM
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Code says all conductors on a circuit need to be in the same raceway (sheath). To me this seems to violate that rule because power in is not in the same sheath as power out.
 
  #12  
Old 12-10-15, 08:21 AM
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Your diagram is incorrect, unless I'm missing something. In your diagram, the neutrals appear to be broken by a switch. The neutral is never broken in a circuit.

Just look at the night light loop only and that is enough to raise concerns.
 
  #13  
Old 12-10-15, 08:43 AM
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They have a miswired switch loop. They are going back on white instead of black.
 
  #14  
Old 12-10-15, 08:44 AM
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Does this look better? Some of the hot up wires I had originally shown as WHITE should have been shown as RE-marked to HOT. Pete caught the one he was working with in the 2-gang box. It appears that you are referring to the other one in the single box (now corrected on the diagram). These wires actually HAD been re-marked in the installation; I failed to show it in the diagram. I can't speak for the upper ends of those wires; I haven't opened up the fan box to look at them. If they are not clearly marked (though the installer was pretty thorough) I'll be sure to re-mark them.
The "new" white wire will connect to the timer switch (not shown here).
 
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  #15  
Old 12-10-15, 08:46 AM
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I would consider it safe. Might not be code compliant, as the hot from one cable is feeding the switch of another (wait for code gurus to chime in)...but IMHO - it's your house, and no one will know.

If it was my house, I'd do it.
 
  #16  
Old 12-10-15, 09:09 AM
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You assume correctly, 21. The text labels for the three appliances were intended to show the intervening mechanisms in the circuit... hots on the bottom, neutrals on the top. I subscribe to your assessment: It ain't purty, but it's functional and safe.
At least half of the wall switches in my (1979) house are unpowered switch loops, as in millions of other houses. I can't help wondering how many homeowners are sticking INCANDSCENT light timers into their bathroom fan circuits, unaware of the dangers involved.
In my house, I've also identified a couple of multiwire branches I'm not too crazy about. The challenge is to live with them without rewiring the whole damned house.
Thanks for your input.
 
  #17  
Old 12-10-15, 09:21 AM
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To get technical - code requires a neutral present at all switch boxes, so your night light circuit wouldn't be compliant anyways.
 
  #18  
Old 12-10-15, 10:21 AM
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My 1979 house just can't seem to morph into a 2011 house no matter how it tries.
 
  #19  
Old 12-10-15, 02:59 PM
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To get technical - code requires a neutral present at all switch boxes, so your night light circuit wouldn't be compliant anyways.
To get even more technical, it wouldn't be a code violation at all because the existing wiring would be grandfathered.
 
  #20  
Old 12-10-15, 03:10 PM
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What looks odd in these drawings is the fact that the repurposed white wire is still connected to what appears to be the supply circuit.
 
  #21  
Old 12-10-15, 03:44 PM
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The switch loops still show the white as the switched hot.
 
  #22  
Old 12-10-15, 07:39 PM
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There is code that states all wires of a circuit need to be in the same raceway or cable. Exception is nonferrous wiring methods such as NM with plastic boxes. The idea is that if you have current in a wire then you get inductive heating and impedance when it goes near iron. Basically you are creating a transformer/choke. Having another wire with the opposite return current next to it cancels this out.
 
  #23  
Old 12-10-15, 08:30 PM
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pcboss, I think i've finally caught your meaning about the "switched hots."
I won't bother you with another drawing, but I will reconfigure my rewiring plan to insure that all three switched hots--the up wires--are the BLACK wires. The two hots--the down wires--will be re-marked whites, and the new repurposed neutral will be a white wire.
Thanks for the attention to detail.
 

Last edited by latelifebiker; 12-10-15 at 09:02 PM.
  #24  
Old 12-10-15, 08:30 PM
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Exception is nonferrous wiring methods such as NM with plastic boxes. The idea is that if you have current in a wire then you get inductive heating and impedance when it goes near iron.
Thank you for answering my question in #12. I'd never read the full explanation.
 
  #25  
Old 12-10-15, 08:55 PM
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According to the boss, the up wire (switched hot) going to the Shower Light should be BLACK.
For consistency's sake, I guess that's what I'll do. It just means swapping your down hot and up switched hot in the S/L circuit to get all three blacks as up wires.
 
  #26  
Old 12-11-15, 05:35 AM
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If the white is the switched hot you end up with two whites at the fixture. This could cause the shell of the fixture to be hot instead of the neutral if the whites are confused.
 
  #27  
Old 12-11-15, 07:17 AM
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I have deleted most of my posts. Sorry for any confusion I might have caused.

Based on PCBoss' comments here is my diagram.

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Last edited by ray2047; 12-11-15 at 12:41 PM.
  #28  
Old 12-11-15, 07:28 AM
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This has been beneficial. If a homeowner can follow this wiring, a normal switch loop will be no problem.
 
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