Wiring

[macuser1983]

Hey there.

I'm helping a friend replace light switches in an old house and we came across this lot when we took an old 2 dimmer switch off the wall http://www.flickr.com/photos/shawniesphotogallery/3971934193/in/photostream/ I have taped the wires up, the were originally all attached to the old 2 dimmer switch. There's two blacks in the light switch at the moment, but I'm not sure if that's right. I think theres a link the to the dining room which is the room next door as since we disconnected all these the light switch in there no longer works. At one point one of the dimmers controlled the wall lights (which are now gone) and the other controls the main ceiling light. I want to put one switch here now, just to control the ceiling light and tape up the wires for the wall lights. How can I work out which wires go where?

Thanks in advance. I'm a total newbie and really need to help my friend out.[/url]

 

[oharaf]

Hey there.

I'm helping a friend replace light switches in an old house and we came across this lot when we took an old 2 dimmer switch off the wall http://www.flickr.com/photos/shawniesphotogallery/3971934193/in/photostream/ I have taped the wires up, the were originally all attached to the old 2 dimmer switch. There's two blacks in the light switch at the moment, but I'm not sure if that's right. I think theres a link the to the dining room which is the room next door as since we disconnected all these the light switch in there no longer works. At one point one of the dimmers controlled the wall lights (which are now gone) and the other controls the main ceiling light. I want to put one switch here now, just to control the ceiling light and tape up the wires for the wall lights. How can I work out which wires go where?

Thanks in advance. I'm a total newbie and really need to help my friend out.[/url]

What have done with the old ends to the wall lights?????

I think you're out your depth here, call a sparky!!

 

[macuser1983]

They've been taped up and plastered up. Not by me though. LOL At the very least I'd like to be able to put the switch on. It had a double switch and the one that did the wall lights was obviously just switching on bugger all.

 

[ban-all-sheds]

Were all the switches without earths, or just this one?

The other bit of bad news for you - as well as now having to sort out the problems caused by you not making a note of which wires went where, if there isn't enough slack in the cables to be able to get the earths connected to the switches, or if there's no earth in the cables, you aren't going to be able to have metal switches.

And even if you can get at them, you still must get an electrician to do tests, because the kind of dangerous idiot who would cut them back in the first place could have done that anywhere, so there is no way of knowing without testing if the earths are connected back to the CU.

In the meantime, please put the old plastic switches back.

 

[macuser1983]

Well I would put the plastic switches back on, but I don't know what the wiring would be for them. Any suggestions?

 

[ban-all-sheds]

Do you have a multimeter?

 

[macuser1983]

I'm buying one tomorrow. Though I've never used one before.

 

[sparkwright]

best get an electrician round. great photo gallery btw.

 

[macuser1983]

Thanks for the gallery compliment, but I really wanting to just put the bloody thing back together. I know there's no earth but it still needs putting back together. LOL

 

[DCC]

And even if you can get at them, you still must get an electrician to do tests, because the kind of dangerous idiot who would cut them back in the first place could have done that anywhere, so there is no way of knowing without testing if the earths are connected back to the CU.

Is the CPC designed to protect the cable or the fitting?

The reason for asking is that surely the person who cuts back the cpc where it is not needed (plastic box, plastic switch) is not in the slightest bit dangerous, all they've done is created a future modification difficulty.

 

[ricicle]

Is the CPC designed to protect the cable or the fitting?

The reason for asking is that surely the person who cuts back the cpc where it is not needed (plastic box, plastic switch) is not in the slightest bit dangerous, all they've done is created a future modification difficulty.

But there lies the danger, for anyone in the future (householder), assuming that earths will be satisfactory because they are there in the cable.
Wiring a system with no earth because of non-conducting accessories falls under the scope of reinforced insulation which has to be properly designed and allowances made for future upgrading.

 

[SparkyNinja]

Is the CPC designed to protect the cable or the fitting?

Circuit Protective Conductor

 

[sparkwright]

Is the CPC designed to protect the cable or the fitting?

The reason for asking is that surely the person who cuts back the cpc where it is not needed (plastic box, plastic switch) is not in the slightest bit dangerous, all they've done is created a future modification difficulty.

But there lies the danger, for anyone in the future (householder), assuming that earths will be satisfactory because they are there in the cable.
Wiring a system with no earth because of non-conducting accessories falls under the scope of reinforced insulation which has to be properly designed and allowances made for future upgrading.

and it's been mandatory to earth lighting circuits since 1966.
in the case of the op here, he states with the switch reds and blacks disconnected the next room doesn't work either. so with those earth wires chopped off he won't have an earth in that room. and the wiring doesn't look very old. there's no excuse for not connecting/terminating earth wires.

 

[DCC]

Is the CPC designed to protect the cable or the fitting?

Circuit Protective Conductor

And yet it's quite clearly there to protect the fittings/appliances not the cable itself (otherwise at the least it would be a sheath of some sort).

 

[sparkwright]

Is the CPC designed to protect the cable or the fitting?

Circuit Protective Conductor

And yet it's quite clearly there to protect the fittings/appliances not the cable itself (otherwise at the least it would be a sheath of some sort).

the cpc protects the fittings and the cable.

if you cut a live cable with cpc it is protected and the fuse or mcb would blow.

if you cut a live 2 core switch wire with no cpc (or neutral) the fuse or mcb wouldn't blow.