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.
Is it supposed to work this way?
On Monday, January 19, 2015 at 9:31:33 AM UTC-5, Madison James wrote:
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?
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 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
Worse one I dealt with was a /three/ switch system
Two standard "two way" switches and the center one a DPDT crossover.
The DPDT had gone bad and my brother-in-law replaced it with a standard
"two way" switch and could not figure out what to do.
He called me and I saw the switch and looked at the wiring and was
completely puzzled as there was one "extra" wire.
I eventually drew out a diagram of how it had to be wired
and finally had enough sense to ask to see the defective switch.
On 01/19/2015 01:27 PM, BenignBodger wrote:
I have been in a friend's house, which probably had a 3-way switch setup
for the living room light. One of the switches had been replaced by a
dimmer (not 3-way) so it was in series with the switch on the other side
of the room (which had to be on to use the light).
On Mon, 19 Jan 2015 06:41:15 -0800, trader_4 wrote:
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.
Is that what you are suggesting?
----/ ------- L -----------/ ---
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
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
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?
"The universe may have a purpose, but nothing we know suggests that, if
so, this purpose has any similarity to ours." [Bertrand Russell]
On Monday, January 19, 2015 at 9:58:26 AM UTC-5, Madison James wrote:
DPB drew a diagram that shows series.
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.
On Mon, 19 Jan 2015 14:31:29 +0000 (UTC), Madison James
Pull both switches out and take pictures of what you have and send
them to a photo sharing site. I use Imgur
Make sure you include all the wires coming into the boxes on the photo
even if you have to take more than one picture of each box.
On Mon, 19 Jan 2015 14:31:29 +0000 (UTC), Madison James
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
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