Which is live wire?
- Thread starter Frankie14
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Is it a socket or a switch?
Is it on an appliance?
The reason I ask is because the colour code is not familiar in household wiring, even in the 70's.
EDIT: HAVE JUST RE-READ YOUR POST. I THINK YOU REFER TO A LIGHT SWITCH?
WHAT ARE THE TERMINALS, WHICH THE WIRES ARE CONNECTED TO, MARKED?
If L1 and C or Common, or L1 and L2, then I suspect the red is the permanent live and the black marked brown is a switched live.
However, I saw a switch the other day where these conductors were connected the other way round, such that the black with marker was a permanent live and the red was live only with the switch on.
If there are other switches fed from the permanent live terminal, (such as a switch on the other side of the wall), you need to connect these to the permanent live, otherwise that light will only work if you have the other one on at the time.
The best thing to do would be to buy a multimeter and use that the work out what's what.
If you just have two wires in the switch and only two terminals on the switch, it should not matter which way round they go.
Is it on an appliance?
The reason I ask is because the colour code is not familiar in household wiring, even in the 70's.
EDIT: HAVE JUST RE-READ YOUR POST. I THINK YOU REFER TO A LIGHT SWITCH?
WHAT ARE THE TERMINALS, WHICH THE WIRES ARE CONNECTED TO, MARKED?
If L1 and C or Common, or L1 and L2, then I suspect the red is the permanent live and the black marked brown is a switched live.
However, I saw a switch the other day where these conductors were connected the other way round, such that the black with marker was a permanent live and the red was live only with the switch on.
If there are other switches fed from the permanent live terminal, (such as a switch on the other side of the wall), you need to connect these to the permanent live, otherwise that light will only work if you have the other one on at the time.
The best thing to do would be to buy a multimeter and use that the work out what's what.
If you just have two wires in the switch and only two terminals on the switch, it should not matter which way round they go.
The red one is permanently live and
the black is live when the switch is turned on.
It could be the other way round if not done exactly correctly so treat both as live.
Brown is the new colour for live. It may have been better to have used a red sleeve (cover) but acceptable.
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Then it doesn't matter which one is which.
Please spend some time learning what light switches do etc.
- http://www.google.co.uk/search?q=electrical+circuits+101
- http://kevinboone.net/electricity.html
- http://web.archive.org/web/20080213151445/http://www.kevinboone.com/domesticinstallations.html
- //www.diynot.com/wiki/electrics:lighting
- //www.diynot.com/wiki/electrics:books
- //www.diynot.com/wiki/electrics
Red-Com
Black with sleeve-L1
Is there an earth cable with the other two wires?
If not is the replacement switch plate plastic or metallic?
If metal forget it, unless you can find an earth cable that may have been cut back and can make a joint to extend it.
Metal accessories are likely to need an earth unless they are class II/double insulated accessories. This will include your light fittings too!
So no earth(CPC) plastic should be used or Class II
Have we solved this problem yet?
Frankie14's dimmer
Black with sleeve-L1
Is there an earth cable with the other two wires?
If not is the replacement switch plate plastic or metallic?
If metal forget it, unless you can find an earth cable that may have been cut back and can make a joint to extend it.
Metal accessories are likely to need an earth unless they are class II/double insulated accessories. This will include your light fittings too!
So no earth(CPC) plastic should be used or Class II
Have we solved this problem yet?
Frankie14's dimmer
P
Paul_C
For a simple 1-way switch (or a 2-way used as a 1-way, with L2 unused) it won't make any difference if you swap them over though.
Want make any difference, put it's the correct way to do it!
P
Paul_C
That the standard method used to install a one way light switch is to connect the permanent live to the com terminal and it is also good practice.
If we take a look at BS7671:2008
134.1.1
This bit becomes relevant:
"Electrical equipment shall be installed in accordance with the instructions provided by the manufacturer of the equipment."
I have yet to see the instruction leaflets that come with switch accessories that suggest you do anything other than connect the permanent live to the com terminal, in a one way switch.
Are you disputing that?
If we take a look at BS7671:2008
134.1.1
This bit becomes relevant:
"Electrical equipment shall be installed in accordance with the instructions provided by the manufacturer of the equipment."
I have yet to see the instruction leaflets that come with switch accessories that suggest you do anything other than connect the permanent live to the com terminal, in a one way switch.
Are you disputing that?
I would say so. Just logic.
They are the Lives, when on, which share a Common supply.
If there were a two-gang switch on which one of the circuits was one-way and one two-way surely you would put both of the supply lives in the Common terminals.
So wouldn't you do the same in a single one-way switch even though it doesn't matter?
Sorry disagree.
Common afaik derives from 2 way switching, relating to the terminal linked common to both switches,
L1 would be your live and L2 your live out.
Maybe in other switching examples ie to have an indicator to show when its off, then common would need to be used.
Common afaik derives from 2 way switching, relating to the terminal linked common to both switches,
L1 would be your live and L2 your live out.
Maybe in other switching examples ie to have an indicator to show when its off, then common would need to be used.
I put a dimmer switch into the bedroom a few weeks ago- queerest set up I've ever seen when I unscrewed the existing one. It's a one way system, I was expecting to find a brown and blue wire going into the L1/Com, but instead found two brown wires doing this, and two blue wires connected together and taped but not connected to anything. Bit perplexed I noted exactly which went to L1 and which to Com and put the dimmer in.
Works fine but what's all that about????
Works fine but what's all that about????
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