I have a friend who has two associated wall switches twenty feet apart.
The first switch turns on the overhead light. The second switch turns it off. So far, so good.
Once the second switch is in the off position, it doesn't matter what you do with the first switch. It won't turn the light back on. Is that supposed to work that way?
Likewise, if the first switch is off, the second switch won't turn the light back on either, no matter what I do with that second switch.
No, the typical wiring for two switches like that is for either one to be able to turn the light on or off. It's called 3 -way and it's typically found at the ends of hallways, top and bottom of stairs, etc. What you have is apparently two switches in series. If the house was wired for 3 way to begin with, it's possible that someone screwed around, didn't replace a switch correctly, etc. For it to be 3 way, an extra wire between the two switches is required. If that's there, it can be corrected. If not, then it is what it is, unless you run a new cable.
First step would be to take a look and see if the switches have two terminals plus ground or three plus ground. And if wires are connected to all three terminals or if two terminals is there an extra unconnected wire in each box?
I am familiar with 3-way, as I have stairs myself that work that way. That's why I asked about this setup.
The first switch, will only turn the light on if the second switch is in a certain position. The second switch, will only turn on the light if the first switch is in a certain position.
Is that what you mean by being "in series"?
I think I understand. What you say is that the house may be wired for two way or three way. If two way, there will only be two wires in the wall. If three way, I should find a third wire in the wall.
Mayhaps can tell simply from the two switches themselves -- if they have the 'on/off' markings on the handles, they are just 2-way on/off switches, not 3-way. 3-way's don't have any markings as there is no correlation between position and state.
OP can do a google search and find a zillion drawings online of how
3-way connections work depending on location of the feed.
That's in series; _both_ switches must be closed to have continuity.
A 3-way has double connections in each that have alternate paths that open/close to complete the circuit irrespective of the position of the other.
Again, DAGS and you'll find all kinds of drawings -- the precise wiring arrangement depends on where the power feed is relative to the location of the switches and the load(s).
As noted above, if the switches have 'on/off' on the handles, they're just 2-way switches; maybe somebody didn't know any better and replaced the originals???
Kind of. But read what I said about looking at what's *connected* to the terminals and a possible *unused* wire. There can be and frequently are other wires coming into/out of the box, eg neutrals, wires feeding other stuff, etc.
Unless this was something added by a homeowner who had the proverbial _no_kluew_, I cannot conceive such a setup actually wired for two light switches in series...3-way's (and 4-way as well for more than two control locations) have been common practice since like, forever.
If a std 3 way installation lost one of the 2 traveller connections, it would act like 2 SPSTs in series. Picture DPB's drawing with 1 "broken" traveller .
If only ONE of the switches is on, the light will be off. However, its possible for 120V to be present at the light. I thought that was considered unsafe. Shouldn't both switches be on the hot side of the light?
That sounds quite possible and it should be easily verifiable. If, on the other hand, some previous homeowner has diddled the wiring then almost anything is possible. I fixed a friend's living room lights that were _supposed_ to be three-way with a switch at each entryway but along the way someone pulled out the three-way toggles and substituted regular SPST toggles which meant that both switches had to be 'on' to get light. Some people's children...
I had the same problem in the front hall when I moved into my almost new house. The electrician whose company wired all the houses still lived in the n'hood and I once mentioned it to him, and he was annoyed and certain he didn't make a mistake! Now I realize it was a mistake to say anything.
You need to change two wires around on one switch.
Learn how two such switches are supposed to be wired. Use a drawing.
Figure out from the way your switches work how they are miswired, Make a drawing, a step at a time, as you put together every aspect of how they work, (including, of course, which is the "first switch" above, and also the color of the wires and if you can tell, which come out of the same piece of romex or BX) and after you stare at it and think about it for 15 minutes to an hour (in segments with breaks up to a day or two in between), you may well figure it out. If not, post it all somewhere and give us the url and someone here will.
At that point it just requires turning off the power and reversing two wires.
Unless Ma and Pa Kettle were rewiring the house, it undoubtedly has the right wires in the wall. What was done wrong is that two of them were connected to the wrong screws. They must be reversed.
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