Two gang switch wiring probs!! Help.

[Mattayscough]

I am swapping over to a new switch and the two wires going into the one gang switch are both red. From my celing rose I have deduced that I have a junction box circuit. Surely there should be one cable with a red and black wire each going into the switch? It looks as though whoever wired it up has run 2 cables from the junction box and used the live wires to run the current to the switch and just clamped the neutral wires to the switch box?

Does anyone have any idea whay they may have used 2 live wires rather than a live and a neutral? I am aware that a neutral wire from a swith will still carry live current. Perhaps the person used 2 red wires to prevent him from having to label the nutral from the switch with red tape?

Help!!

 

[andy]

I am swapping over to a new switch and the two wires going into the one gang switch are both red. From my celing rose I have deduced that I have a junction box circuit. Surely there should be one cable with a red and black wire each going into the switch? It looks as though whoever wired it up has run 2 cables from the junction box and used the live wires to run the current to the switch and just clamped the neutral wires to the switch box?

Does anyone have any idea whay they may have used 2 live wires rather than a live and a neutral? I am aware that a neutral wire from a swith will still carry live current. Perhaps the person used 2 red wires to prevent him from having to label the nutral from the switch with red tape?

Help!!

er... there isnt a neutral in the switch (unless its looped from switch to switch, rare)there is a live and sw. live. ideally, all switches should be in twin red/brown. and why bother sleeving different cores and marking switch cabls when you have twin red

 

[Mattayscough]

Cool. All of the diagrams in my manuals show the switch live as a black wire so I assumed that my wiring as wrong.

The live red wires that have been used are in two seperate cables with the nutral wires have been clamped onto the box. Is this normal?

 

[andy]

The live red wires that have been used are in two seperate cables with the nutral wires have been clamped onto the box. Is this normal?

depends how its been wired. the feed could come fom another light to the switch, neutral is in terminal block to keep it connected and the live goes thru the switch

 

[ban-all-sheds]

I am swapping over to a new switch and the two wires going into the one gang switch are both red.

One gang switch? Post topic is "Two gang switch wiring probs"??

From my celing rose I have deduced that I have a junction box circuit. Surely there should be one cable with a red and black wire each going into the switch?

That's the usual way of doing it..

It looks as though whoever wired it up has run 2 cables from the junction box and used the live wires to run the current to the switch and just clamped the neutral wires to the switch box?

With lighting circuits it's very important to not automatically make the red=live black=neutral associations, because as you point out, the normal way of doing it ends up with the black being switched live.

And the blacks should not be connected to the switch box, unless they are connected to the earth of the lighting circuit, and they are sleeved green/yellow at both ends.

Does anyone have any idea whay they may have used 2 live wires rather than a live and a neutral?

They didn't use 2 live instead of live and neutral - they used 2 red instead of red & black.

I am aware that a neutral wire from a swith will still carry live current.

Then it's not a neutral, is it?

Sorry to labour the point, but it is a very important one, and getting it wrong at ceiling roses (i.e. thinking that all the blacks are neutral) is the commonest mistake people make, and it leads to blown/tripped fuses/MCBs and wrecked switches...

Perhaps the person used 2 red wires to prevent him from having to label the nutral from the switch with red tape?

He may have used 2 red wires because he didn't realise that it was common practice to use the black for switched live. Seems a lot of effort to go to just to avoid having to sleeve the black.

You are sure, are you that the blacks are not really neutrals, i.e. someone has taken live & neutral to the switch, and switched live and neutral from the switch to the light, and has been stupid enough to use the box earth terminal to join the neutrals instead of choc-block?

Is there an earth wire in the cables? Are they connected to anything?

 

[Mattayscough]

one gang/two gang. Not bothered. Just don't want to blow the bloody doors off!!!

Sleeved earth is joined to the box too. Two red/ live wires to the switch from two seperate cables. The black (and I assume redundant|) wires clamped into another screw in the box.

Can see why there would be any other wires from other lights/switches. I'm fairly sure that the installer has just used the reds of 2 cables instead of a single two core and earth and used both red and black. A waste of cable but at least it reduces the chances of anyone getting a painful surprise.

 

[pdcelec]

one gang/two gang. Not bothered. .

Strange reply.

Just don't want to blow the b****y doors off!!!.

Waht a great film that was

Sleeved earth is joined to the box too..

that is correct

Two red/ live wires to the switch from two seperate cables. .

Could be correct but needs confirmation using an appropriate meter

The black (and I assume redundant|) wires clamped into another screw in the box..

Never assume anything when it comes to something that could potentially kill you. This needs confirmation using an appropriate meter

Can see why there would be any other wires from other lights/switches. .

do not understand this sentence

I'm fairly sure that the installer has just used the reds of 2 cables instead of a single two core and earth and used both red and black. .

Why are you so sure? Did you do the wiring?

A waste of cable but at least it reduces the chances of anyone getting a painful surprise.

What are you basing this statement on?

 

[Mattayscough]

Well there are only 2 cables coming into the box from the junction box and the 2 reds are connected up. Therefore, I am assuming that as the switch actually works, then both must be carrying live charge to complete the circuit.

Sadly the tone on this forum seems to be to look to closely at people's spelling and stuff and whether they have used to correct electical terms (bit confusing as I am a local government officer) rather then offering practical advice. Perhaps I have misjudged the tones of the responses. Sorry if this is the case.

 

[Spark123]

When you say the neutrals are clamped into another screw in the box, do you mean into terminal block? :

If not, any chance of a picture?

 

[Mattayscough]

no there is an additional clamp in the plastic of the box to which the black wires are fitted. It is not the earth wire because this is joined to the box on a seperate claim.

 

[Spark123]

Plastic back box?
Any chance of a picture?

 

[Mattayscough]

Yeah plastic back box. Blacks are clamped in there too, as well as the earths. And the actual switch is fed by the two reds. I think that whoever installed the switch has just used two cables instead of using one red and black single 2 core and earth cable.

And no, it wasn't me!!!

 

[Spark123]

If I have it correct, you have two cables entering the plastic back box. From these cables the earths are jointed together in the earth terminal of the back box, the blacks are jointed together (how?), and one red is connected to C and the other to L1 on the switch.
Any chance of a picture of how the blacks (sounding more like a neutral) are connected?, to post a picture see: //www.diynot.com/forums/viewtopic.php?t=8463

 

[Mattayscough]

Spark123. That's about it.

If I remember the blacks are in a clamp similar to that of the Earth on the other side of the wall box.

I will have to check tonight as I am at work but I am fairly sure that that is how it is. The actual switch is connected as you have discribed.

 

[Spark123]

The neutrals should be connected using insulated terminal block or similar, you should not be able to touch the neutral conductor from outside the confines of the back box.