I replaced three light switches in our bedroom, two are 2-way and one is an intermediate switch. I carefully followed the existing wiring, but now one of the 2-way switches if it’s switched on makes the other two switches not work. If it’s switched off then the other two switches work as intended. What have I done wrong?
Replaced 3 lights switches and one keeps all of the lights on and makes the others not work!
- Thread starter RogPJ
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Sounds like you have not been as careful as you think.
The one one you stated"if its switched off then the other two work as intended" sounds like you have wired that one wrongly.
It will be one of the 2 way switches and the "com" connection is wrong, it is in place of one of the other two terminals on that switch.
Note - with 2 way or intermediate switches there is no "on" and no "off" position there are merely just two positions that merely let the light be on or off depeding upon the positions of the other switches.
I am assuming that when you say the two other switches work as intended then you have a total of two combinations that light the light up and two combinations that leave it unlit.
The one one you stated"if its switched off then the other two work as intended" sounds like you have wired that one wrongly.
It will be one of the 2 way switches and the "com" connection is wrong, it is in place of one of the other two terminals on that switch.
Note - with 2 way or intermediate switches there is no "on" and no "off" position there are merely just two positions that merely let the light be on or off depeding upon the positions of the other switches.
I am assuming that when you say the two other switches work as intended then you have a total of two combinations that light the light up and two combinations that leave it unlit.
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Wired them incorrectly would be the most obvious answer !
You must have the same wire connected to the COMs in the two-way switches and that wire not connected to the intermediate switch; just passing through.
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Actually I just thought too.
I was thinking of one way they might already be wired and maybe EFLI was thinking of the other way it might be already be wired too.
I was thinking of one way they might already be wired and maybe EFLI was thinking of the other way it might be already be wired too.
Yes, I was only thinking of one way, but -
the other way is sort of the same because the two strappers must not be connected to COM.
That sounds like the answer. The intermediate switch by one side of the bed and the 2-way switch by the door were easy to replace as they matched the new switches. The 2-way on the other side of the bed was a really old light switch which didn’t have Com marked. I assumed that L1 on the old switch would be Com on the new.
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Most commonly on two way switches the "common" is marked with a "C" or a "Com", and the other two are marked as "L1" and "L2".
on some switches "L1" are intended to be used for 1 way switching but on others "L2" is used instead.
On some switches they are not marked as Com, L1 & L2 but rather as L1, L2 & L3 so it can be a bit confusing.
There is more than one way to connect two switches in the "two way switch" configuration too.
So, overall, it can be a little confusing.
There are 3 basic ways of installing lighting circuits too.
One way is to put the switching wires in the ceiling rose or light fitting.
Another way is to do the same but inside the switch back box.
Another way is in a separate junction box.
Any installation (your home for example) could all be wired similar but might be wired with features of 2 or 3 of those systems.
And, just to make things even more complicated, there is also something that is described as a "Two way Hamburger" amongst other things, that is rare, I think, but adds another potential danger into the mix.
By now you might be thinking that it would be easier to land a satalite on the Sun, you might be correct in that line of thought.
Good luck, as always stay safe
on some switches "L1" are intended to be used for 1 way switching but on others "L2" is used instead.
On some switches they are not marked as Com, L1 & L2 but rather as L1, L2 & L3 so it can be a bit confusing.
There is more than one way to connect two switches in the "two way switch" configuration too.
So, overall, it can be a little confusing.
There are 3 basic ways of installing lighting circuits too.
One way is to put the switching wires in the ceiling rose or light fitting.
Another way is to do the same but inside the switch back box.
Another way is in a separate junction box.
Any installation (your home for example) could all be wired similar but might be wired with features of 2 or 3 of those systems.
And, just to make things even more complicated, there is also something that is described as a "Two way Hamburger" amongst other things, that is rare, I think, but adds another potential danger into the mix.
By now you might be thinking that it would be easier to land a satalite on the Sun, you might be correct in that line of thought.
Good luck, as always stay safe
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