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I've come across a light controlled by three switches. It's unique to me because any combination of switches must be in the "on" position for it to work. All three must be "off" for the light to go off. It's not a typical multipole switch.

I can naively imagine that three normal switches in the same circuit connected to the same light would behave this way but I've never seen this before.

Is this safe? Is it a code violation? What is the appropriate terminology to describe this setup?

  • Being in parallel does not mean multiple hot lines - it means one hotline and drops to each switch. See my answer I think you will need to pull the switches out and have a look see - See my answer - I think you will find it resolves your real issue and answers your questions. – Ken Mar 21 '18 at 9:27
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The three switches are simply wired in parallel. Each switch’s hot terminal is connected together and each load terminal is connected together. If any switch is on, power will pass to the light.

While it is unusual, I don’t see any reason it would be against code. I also don’t see how it could be considered dangerous.

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  • With multiple hot lines won't the power be out of phase? The line and load at each switch will be energized if any of them are on – Matthew Mar 21 '18 at 6:54
  • if there was an issue, it would have presented itself by now. – dandavis Mar 21 '18 at 8:08
  • @Matthew My answer assumed you meant wall switches. Your comment above seems to imply you are talking about circuit breakers. If that is true, that is entirely different and quite unsafe. Please clearify. – DoxyLover Mar 21 '18 at 9:15
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  1. Your switches are in parallel as the other answer.
  2. You only have 1 phase of power - so there is no way the same phase can be out of phase with itself in your example.
  3. I would venture a good guess a DIY'er replaced the 4 way switch with something other than a 4 way switch like a 3 way or something else and passing through the hot to the load.
  4. While not a code violation - the possibility that something could pose an issue exists .. my reasoning is that it is not normal and I suspect a DIY'er was in the switch boxes and wired things - the possibility to have a live wire floating around or some other unknown is enough to make me fix it right.
  5. So here is what you should do to fix that - take a look at the wiring of the switches and see if they match the drawing below.

Grey in drawing is Neutral (really your White wire), Red is your travelers (they are hot at times), black is the hot wire, green or copper is ground.

Example 4 Way Wiring source first load last:

4 Way wiring

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  • In that drawing, red and black are travelers, there is not hot wire as travelers replace the hot wire. Also that diagram is a hot mess, I know it isn't yours. That illustrator shouldn't quit his day job. – Harper - Reinstate Monica Mar 21 '18 at 17:50
  • @Harper yes you are correct however DIY'er must understand they carry Voltage - Hot ..don't touch unless you want to get electrocuted that was my point. I know at times one will be hot and one will not but if they are treated as hot while working on them; you should not get electrocuted or shocked. – Ken Mar 22 '18 at 19:36

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