Lighting Circuit and Switch Wiring

[morpheus83uk]

Hello,

I have been doing some searching around and found this forum and site as a whole to be quite useful so I figured I would join!

I am having some issues with my electrics where by my LED bulbs stay dim when the switch is off and have found (I think from this site) that swapping the switch to a double pole switch will isolate the neutral and the live from the light thus no residual voltage can light the LED's. Would I be correct with this?

Secondly I have looked at the switches in different rooms and I am unable to work out what's happening. I have two cables (twin core + earth) going to the socket and just the blue cores are connecting to the switch. The two brown cables are together in a connector and the same for the earths. Does anyone know what the setup for this is?

As everyone loves a good picture I have attached one of the switch... Any help on understanding this would be great.

Many Thanks

James

Here is the wiring behind the switch:

Untitled

• morpheus83uk
• 4 Sep 2014
• 1

 

[winston1]

The switch is wired wrongly. The brown cores should go to the switch and the blues joined together.

This will probably fix your dim when off LED problem as well.

 

[morpheus83uk]

Thank you for your reply.

So does this mean that I should have the two brown wires going into the switch opposed to a brown and a blue?

Could you please also explain why I have two physical cables coming to the switch opposed to one? I always thought it was a single cable and the loop was done via the ceiling rose?

Many Thanks

James

 

[endecotp]

I have two cables (twin core + earth) going to the socket and just the blue cores are connecting to the switch.

Who did that wiring?

Is is totally incompetent, and you should perhaps assume that your whole house is a DEATH TRAP.

 

[JohnW2]

So does this mean that I should have the two brown wires going into the switch opposed to a brown and a blue?

Yes, that's what he meant - it seems probable that the two browns should go to the switch and the two blues be joined in the bit of connector block (i.e. the opposite of what you now have). Assuming that the blues and browns have been wired correctly (brown=line/live, blue=neutral), what you have got is definitely dangerous - so see below.

Could you please also explain why I have two physical cables coming to the switch opposed to one? I always thought it was a single cable and the loop was done via the ceiling rose.

There's nothing wrong (or all that unusual) with the 'looping' being done at the switch, provided it is done correctly!

As endecotp says, if someone has made such a basic (and dangerous) error as getting the browns and blues transposed in that switch, I think you should seriously worry about what other dangerous horrors may exist in your electrical installation, and would strongly advise you to get the whole installation inspected by an electrician.

Kind Regards, John

 

[morpheus83uk]

Brilliant news!!! Just as I suspected considering this is what I have found everywhere else in my house! I wouldn't mind but its only 10 years old!!

I think I will be looking at a few of the switches first to see if they are the same as I am doing some work this weekend on changing some of the battens so I will have a look at what's going on where its just this has completely baffled me!

So although its a death trap waiting to happen would putting the two browns into the switch make it a little more safe?

I have never known that the loop can be done at the switch so for my own learning could anyone explain how this would work or if there is a diagram to link me to so I know how its done

James

 

[endecotp]

So although its a death trap waiting to happen would putting the two browns into the switch make it a little more safe?

IF this is the only mistake, then re-wiring that switch so that it switches the brown instead of the blue would be an improvement.

BUT it's quite possible that whoever did that also wired the other end of one or other of those cables. If they've got it consistently wrong, i.e. they've used brown for neutral and blue for live everywhere, then swapping just that switch would make it MORE DANGEROUS.

I have never known that the loop can be done at the switch so for my own learning could anyone explain how this would work or if there is a diagram to link me to so I know how its done

Isn't there a "lighting circuits FAQ" at the top of this forum?

But to be honest, if this isn't something that you can work out yourself, are you sure you should be working on it?

 

[morpheus83uk]

Great I will take them off and then test them all to see what's live where and mark them up before doing anything.

Not that I can see however there is the lighting wiring diagrams but I cant see one for a loop done for a switch unless I have missed it. I did have a look there originally before asking the question.

I have done stuff before however when I looked at it I was baffled at how it worked which is why I was asking the question as it wasn't anything I have seen before. I have always known that the lighting circuit goes through a ceiling rose with a single cable going from the ceiling rose to the switch. So when there were two cables and using the two blue cores it didn't make any sense from what I know and have done previously.

 

[Taylortwocities]

Not that I can see however there is the lighting wiring diagrams but I cant see one for a loop done for a switch unless I have missed it. I did have a look there originally before asking the question.

Well you didn't look very hard then

It is in the bit titled
"Looping at switches"
HERE
//www.diynot.com/wiki/Electrics:Lighting-Circuit-layouts

 

[JohnW2]

Well you didn't look very hard then It is in the bit titled "Looping at switches" HERE //www.diynot.com/wiki/Electrics:Lighting-Circuit-layouts[/QUOTE]
I think you're probably being a bit unfair - the OP was effectively directed to the "Wiring Diagrams for Lighting Circuits" sticky, not the wiki.

[is it not about time we got rid of that sticky?]

Kind Regards, John

 

[morpheus83uk]

Thanks for that. I am now even more confused then. I understand the diagram you posted however it shows the three wires going to and from the switch. So one in one out and one to the light. However my switch only has two cables coming to it so I am guessing one to the light and the other from the previous feed. If that's the case how come other switches in my house are the same? I seem to be missing a wire some where.. can anyone explain where it's gone?

Many Thanks

James

 

[JohnW2]

Thanks for that. I am now even more confused then. I understand the diagram you posted however it shows the three wires going to and from the switch. So one in one out and one to the light. However my switch only has two cables coming to it so I am guessing one to the light and the other from the previous feed. If that's the case how come other switches in my house are the same? I seem to be missing a wire some where.. can anyone explain where it's gone?

If the circuit 'loops' to a further switch/light, there will indeed be a third cable (as in diagram), going to the next switch (and thence to the corresponding light, and perhaps with another cable going from there to the next switch/light etc, etc.).

There are two possibilities for what you are seeing. Firstly, it could be that you are looking at the last switches (and lights) on a 'run', hence no third cable going to the 'next switch/light'. Alternatively (perhaps more likely, since you have seen multiple examples of this 'two cable' situation), it could be that each switch/light has been wired on a separate 'circuit', the feed to each of the switches coming directly from your CU or perhaps from a junction box somewhere; that would be a fairly unusual arrangement, but there's nothing actually wrong with it.

Hope that helps.

Kind Regards, John

 

[endecotp]

Thanks for that. I am now even more confused then.

You're out of your depth. There is a danger that you could make things worse rather than better.

 

[JohnW2]

Thanks for that. I am now even more confused then.

You're out of your depth. There is a danger that you could make things worse rather than better.

I'm inclined to agree. As I wrote:

... and would strongly advise you to get the whole installation inspected by an electrician.

Kind Regards, John

 

[morpheus83uk]

Yes I thought that but I wasn't too sure. I will do some testing and find out what's where and then wire it up. Hopefully I can make it alright either that find a qualified electrician to sort it out.