Old Light Switch Replacement - Keep blowing the 5 Amp Fuse!

[Cluffstarr]

Hi all, First post on here although I've used the forum for some helpful tips in the past...

I've searched through the threads but I cant find an answer to my particular issue...

I have just bought a 1930s house and need to replace a couple of knackered light switches. They are the very old round bakelite style ones. . When I took one apart, I found one connection at the top and two at the bottom in a triangle shape. There were two black wires coming into the connection at the top and a red wire from each at the bottom. One of each colour comes from the fusebox, the other black and red go off to the light fitment.

Where should I fit each wire on the new light switch which has a COM, L1 and L2 connections? I wired it up as I would a normal light switch but forgot in new wiring it is just the switching circuit that comes to the light switch and hence blew the 5Amp main fuse!

I did think I should just connect up the Neutrals in a connector block and switch the lives through COM and L1 but before trying I thought I would seek some sound advice before blowing more fuse wire!

Thanks, Cluffstarr

 

[Chri5]

Would there be another switch somewhere? As in the light is controlled from two switches?

 

[Cluffstarr]

Would there be another switch somewhere? As in the light is controlled from two switches?

There is no other switch! I think that the old switch simply switched the two red live wires while the top socket worked as a connection point for the black wires. I'd just like to confirm if anyone else has experience of this...?

 

[securespark]

We need a photo of the old switch....

 

[Cluffstarr]

I'll try!

 

[bernardgreen]

On some old bakelite and ceramic switches there was often a "spare" terminal which could be used to anchor the neutral. It wasn't labelled as N or Neutral or anything as the manufacturers used the same moulding for one way or two switches by fitting one or two set of contacts. That was in the days when the electrician could see the works of the switch and know what it was and labelling wasn't so necessary.


So for this OP the reds go one each to COM and L1 and the two blacks join in a separate single terminal block.

 

[Taylortwocities]

I did think I should just connect up the Neutrals in a connector block and switch the lives through COM and L1 but before trying I thought I would seek some sound advice before blowing more fuse wire!

Please note that just because a wire is black (or blue) does not necessarily mean that it is a neutral.

Have a look at the lighting diagrams in the WIKI and you will understand more.

 

[Cluffstarr]

On some old bakelite and ceramic switches there was often a "spare" terminal which could be used to anchor the neutral. It wasn't labelled as N or Neutral or anything as the manufacturers used the same moulding for one way or two switches by fitting one or two set of contacts. That was in the days when the electrician could see the works of the switch and know what it was and labelling wasn't so necessary.

I think this must be what I have. I will report back if I can sort it this afternoon - thanks very much to all for the advice. If I'm still stuck I'll try and take some pictures!

 

[Cluffstarr]

Linking the Neutrals together and switching just the lives and all is sorted. Cheers for the help!

 

[ban-all-sheds]

On some old bakelite and ceramic switches there was often a "spare" terminal which could be used to anchor the neutral. It wasn't labelled as N or Neutral or anything as the manufacturers used the same moulding for one way or two switches by fitting one or two set of contacts. That was in the days when the electrician could see the works of the switch and know what it was and labelling wasn't so necessary.

It's quite possible, but inadvisable, with a modern 2-way switch, to put permanent lives in L1 and neutrals in L2.

 

[bernardgreen]

It's quite possible, but inadvisable, with a modern 2-way switch, to put permanent lives in L1 and neutrals in L2.

Very inadvisable In many switches this can end up with transient arcing shorts between Live and Neutral as the moving contact swings from Live to Neutral. Not lomg enough to trip an MCD but very damaging to the switch contacts.