Need help in replacing 3 gang 1-way switch to 3 gang 2-way

Joined
5 Aug 2025
Messages
7
Reaction score
2
Country
United Kingdom
Hi experts,

Found on google that we have below difference in the naming scheme between 2-way switch, and 1-way switch:
L1 on old switch is Com on new switch.
L2 old is L1 new
L3 old is L2 new
I did exactly the same but no luck as all of my electricity gone due to fuse tripped which might be due to some kind of short.
My current wiring is like one:

1754424562612.png



New switch:

1754424655263.png


Thanks in advance.
 
Thanks for the replies.
I couldn't take the picture of the new one with the cables as had to revert back in panic as the two RCDs were tripped.
But what I did is just to use the below coding:
L1 on old switch is Com on new switch.
L2 old is L1 new
L3 old is L2 new
So, the brown ones connected to Com, black to L1, grey to L2 and one brown to L1 in the down row as it's connected to L2, as per above picture.
 
Hi experts,

Found on google that we have below difference in the naming scheme between 2-way switch, and 1-way switch:
L1 on old switch is Com on new switch.

Yes


L2 old is L1 new

No


L3 old is L2 new

No.

1754432808451.png



I did exactly the same

Did you?

1754482426396.png



the two RCDs were tripped.

Getting L2 & L3 mixed up won't trip RCDs.

Putting wires from 2 different circuits in the same switch section will.

1754434872704.png
 

Attachments

  • 1754434014688.png
    1754434014688.png
    831.6 KB · Views: 53
Last edited:
Hi again,

After the above gr8 advice, good that there was no fuse trip and I was able to use the first and the last switch without any issue but the middle one is keeping the light on. I used the old switch and same issue is replicating there. I matched the cables many times but not seeing any difference from the original one (which I captured the snapshot before I was changing the switch in which there was no such issue), so all 3 cables (grey, black and brown) are intact but still I can't turn off the light. Any suggestion please?
 
I would say the switch is faulty but you say when you use the old switch it is doing the same.

Does the light go out if you remove the brown wire from the switch?
Put the brown wire in a separate connector before switching the supply on again.
 
Yes, after removing the brown cable it turned off. I moved it to another connector but it didn't turn on there.
I meant a separate piece of connect block to isolate it so that it doesn't short on anything or give you a shock while removed from the switch.

Anyway - put the Brown back in L1 and swap the Black and Grey In L2 and L3.
Now what happens?
 
Thanks for the suggestion but I don't want to play further as last time I swapped L2 and L3 and it was a fuse trip :)
I'm gonna use the electrician for this but can't do it now. May I get an idea that if I leave this in the same situation for sometime, will it cause any issue as other two connectors are working fine? Could this scenario disrupt the other components?
 
Then you must have swapped L2 & L3 between switches, not within.
No, I didn't swap the cables between the connectors. I followed the rule which I quoted in my first update i.e:
L1 -> Com
L2 -> L1
L3 -> L2
But these were done within each connector - but then both the RCDs were tripped.
 

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Back
Top