Dual Hot wires on single pole switch

Dual Hot wires on single pole switch
Dual Hot wires on single pole switch
2021-04-26 16:01:22

I went to change out a single-pole bathroom mirror light switch with a HS200. However I soon discovered that both leads were hot as opposed to normal line and load flow for a single pole switch. I did a little research and believe it is because the mirror lights are probably wired in series and I guess that requires power on all the time but not really sure?? Nevertheless I did not proceed. So my question is can a HS200 line and load leads both be connected to a hot wire? Thanks. 

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Re:Dual Hot wires on single pole switch
2021-04-26 17:19:47

@Senior_Vagabond That's not really possible - if both lines were 'hot' then the switch would be moot, yes? 

 

Are you possibly detecting with a non-contact voltage detector? 

It's common for those to falsely detect voltage if the wires are in close proximity to each other (even through the insulation!) 

So I would suggest - turn off breaker, remove the 'dumb' switch, separate the two wires and then turn breaker back on and check again. 

 

If it really IS live, the other way that can happen is you have a Neutral issue and your system somewhere is using a shared Neutral 

 

You mention two lights (extremely doubtful that they are wired in series) - do these have separate switches or does that one switch control both? 

If single switch, even if only one load wire leaving the switch box, the second light would be wired in parallel to the first (with the connection to the 'second' taking place at the 'first' light fixture box) 

 

Please note that I do not work for, or have any affiliation with, Kasa TP Link. I am simply an enthusiast who likes helping if I can.
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Re:Dual Hot wires on single pole switch
2021-04-26 22:20:50

@Bethel.8009 

 

I tested the leads again (as I have done with the past 25 switches replaced, smart and dumb) and both still read hot. There are 2 switches in the gang box both connecting to different lights and both are hot/hot. Also forgot to add that there is no ground connection to either switch (copper grounds are bundled with wire nut in back of the box). I am assuming because this is a bathroom circuit it is GFI and I don't think it is required but not sure. Regardless the old toggle switches have worked with no issues for 17 years the way they are. I replaced them with rocker switches in the same manner until I know more. I am planning some high voltage circuit changes to support a z-wave smart switch on a heat pump in about a month and will check with an electrician at that time. I did read several articles 2 hot leads are possible but just don't know why in this case. Strange sad

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Re:Dual Hot wires on single pole switch
2021-04-28 00:16:18

@Senior_Vagabond 

Think about this for a minute:

If the Load wire was really hot, then the lamp would be on 

Also, the Switch would not be doing anything, since both sides would reputedly be at same potential. 

 

I think there must be an issue with the Neutral side (of the lamp) and you are reading no-current voltage through the bulb; I suspect if you were to remove the bulb from the fitting controlled by that switch, you will no longer see voltage on that load wire which would validate that route is from where your voltage is coming . That would still require some investigation as to why you are getting voltage via the Neutral so good to discuss with your Electrician. Please do report back on what you find, it's certainly got my curiousity. 

 

  

Please note that I do not work for, or have any affiliation with, Kasa TP Link. I am simply an enthusiast who likes helping if I can.
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