Changing switches from 2-way to 1-way

[garmcqui]

I want to change a 2-way light switch arrangement to an ordinary 1-way, but just to be difficult it's the slave switch I want to keep. The master switch will just have a blanking plate fitted.

This is exactly like the old setup:



So I've used two choc blocks and joined the wires behind the master switch as shown in the photo.



It's working fine. However, when I stick a voltmeter on the black wire (which was the COM wire, and is now unused) it's telling me there is 90-100V on it? Despite it being disconnected at both ends?

So, is there a better way to do what I've done, and why is the black wire registering a sizeable voltage?

Cheers

 

[JohnW2]

So I've used two choc blocks and joined the wires behind the master switch as shown in the photo. .... It's working fine. However, when I stick a voltmeter on the black wire (which was the COM wire, and is now unused) it's telling me there is 90-100V on it? Despite it being disconnected at both ends?

If it really is disconnected at both ends, that will just be 'induced voltage' from other cables - nothing to worry about.

If it's working OK, you have in some senses been 'lucky', since I think that method is reliant on the switches having been wired in a certain way. What I would have done was to simply use connector blocks to emulate the removed master switch - assuming you are keeping the existing 2-way slave switch (but using it only as a 1-way one), I would have connected together (in one bit of connector block) the wire that had been connected to COM and either the wire that had been connected to L1 or L2, and leave the other (that which had been connected to L2 or L1) disconnected (safely terminated in a bit of connector block). That emulates the removed master switch in one of its positions. If the slave switch then worked 'upside down', I would swap the 'L1' and 'L2' wires in the connector blocks at the (ex) master end.

Kind Regards, John

 

[EFLImpudence]

L1 and L2 are line and switched line.


Garmcqui - Put the black in with the grey at both ends.

 

[EFLImpudence]

If you saw that before I edited.
I changed my mind.

 

[garmcqui]

Thanks for the replies.

John - very detailed, makes sense. I was mildly surprised it worked first time!

EFLImpudence - can I please ask why put the black in with the grey at both ends? I have currently terminated each end in a separate choc block.

 

[EFLImpudence]

Just to keep it out of the way and save chock blocks.

You could also put both ends in the earth connection.

 

[securespark]

That is an accepted way to deal with disused, "floating" conductors: tie each end down to earth.