How do I wire this switch..?

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Old 05-31-18, 03:10 PM
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How do I wire this switch..?

Okay, I was stupid and didn't take a picture of the existing switch wiring before disconnecting it, but am 99% certain I remember what it looked like.

I'm installing a new LED vanity light and want to replace the existing Levitron rocker switch with a sliding LED-rated dimmer switch. My house was built in `64 and has obviously seen many DIY projects from previous owners who took a lot of shortcuts, this switch being one of them.

The switch box has a 2-wire cable running to the light box with black, white, and a bare ground wire and I've checked these wires for continuity with a multi-meter, so wiring this up should be a simple matter. However, the cable feeding the switch box only has a single black (hot) wire in it, nothing more.

Now if I recall correctly, that single black wire was connected to the bottom (hot) screw on the rocker switch and both the black and white wires running to the light box were connected to the top (neutral) screw. Can that be right? The rocker switch has been in service for years, but I want to be sure I wire the dimmer properly so I don't fry it the first time I turn it on. Any help would be greatly appreciated.
 
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Old 05-31-18, 04:00 PM
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Re-install the old switch and make a photo for reference. Then install the dimmer.
 
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Old 05-31-18, 07:59 PM
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However, the cable feeding the switch box only has a single black (hot) wire in it, nothing more.
I've never seen a cable with only one wire. Are the other wires cut off or perhaps tucked into the back of the box ?

Your wiring does not sound correct. Neutral shouldn't be on the switch.



 
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Old 05-31-18, 08:14 PM
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Well that confusing, first you say there's a black, white and ground wire, then you say there's only a black wire,
Older switches did not even have a neutral,
Sounds like a simple switch loop, the white wire should have had a piece of black tape around it to denote it as a switch loop.
It does not matter which side of the switch which wire goes to which screw as long as the ground is is on the ground screw.
https://images.search.yahoo.com/yhs/...g&action=click
 
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Old 06-01-18, 05:14 AM
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It sounds like the black and white on the switch should have been wire nutted together with a pigtail to the switch, measure between that black and ground and you should get 120 volts.
Geo
 
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Old 06-01-18, 06:37 AM
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It sounds like a conductor is missing. Two blacks and a white in cables would normally be two black and two white.
 
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Old 06-01-18, 07:25 AM
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Sounds to me like a switch loop,
 
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Old 06-01-18, 07:25 AM
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Thanks for all the replies, but evidently I confused some of you. My apologies for that, and allow me to clarify:

I thought what I wrote indicated there are two cables. The first one (let's call it Cable A) has a black, a white, and a ground wire and runs from the switch box to the light box with no other connections in between. The second cable (Cable B) is the one that feeds power to the switch box, through a single black (hot) wire.

To further clarify, there are no other wires in the box or tucked away in the wall behind the box. I know this because I removed the old metal box so I could replace it with a 2-gang new work box, thus exposing both cables inside the wall. In the case of Cable B, it looks exactly like Cable A but the white and ground wires have been removed as far back as I could access it in the wall. Again, an older house with, as I've discovered along the way, evidence of some unusual DIY practices.

The solution to wiring the switch, however, was to connect both black wires to the "hot" screw on the switch with the white wire being connected to the "neutral" screw, so when the switch is thrown it completes the circuit running to the light box.

And now, to further complicate things, the reason I installed a 2-gang box is because I want to add an outlet here, but I don't want it to be a switched outlet, I want it to always be hot. Could this be done if I leave Cable A in place, but run the Cable B hot wire to the outlet first, and then run black and white jumpers from the outlet to the switch?
 
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Old 06-01-18, 07:37 AM
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You have an issue. Normal switches do not have a neutral. They switch the hot.

With only those wires connected to a switch you do not have a neutral. But then you say the light works. Something seems to be still missing.
 
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Old 06-01-18, 07:41 AM
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No neutral in the box so there is no way to power the outlet, as mentioned before the white conductor from the light should be recolored black , itís not a neutral
 
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Old 06-01-18, 08:18 AM
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white wire being connected to the "neutral" screw,
No neutral on a standard switch with no extra functions. Both screws are for hot wires.
 
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Old 06-01-18, 08:45 AM
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Everyone is correct but me; I've been using wrong terminology.

No hot or neutral screw on switches, but there are brass and silver screws and the neutral wires do not get connected to switches, but they do get connected to either side of an outlet, yes?

Yes, the light works when wired as described but something is missing, that being the neutral wire from the cable feeding power to the switch box.

And without a neutral the only way to power the outlet with the existing wiring would be as a switched outlet. Otherwise, if I want the outlet to be hot all the time I need to find a new power source to feed the outlet and wire it as an end-of-line outlet, correct?
 
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Old 06-01-18, 08:46 AM
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NO. If there is no neutral you cannot have a receptacle.
 
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Old 06-01-18, 08:55 AM
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Why not? All I need to do is wire it in series with the light.
 
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Old 06-01-18, 10:23 AM
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Line voltage is never wired in series because the voltage is split between them depending on the impedance. One might get 50v and the other 70 volts.

https://www.electronics-tutorials.ws...tor/res_8.html
 
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Old 06-01-18, 11:01 AM
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Okay, wrong terminology again, but the plan has changed.

The ceiling access panel to what we can euphemistically call my attic is right next to the bathroom door, so I took a look up there and saw a number of different wire runs, including a few that pass through the ceiling to feed the rooms below. Ought to be able to tap into one of them to get power to the outlet, but I'm thinking it might be wiser to call in a pro than tackle that myself.
 
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Old 06-01-18, 11:02 AM
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Could you please post pictures ?
 
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Old 06-01-18, 01:26 PM
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