Extra wire for security light

[Heather7000]

I have just moved in to a new house and need to put in a new security light.

There are four wires coming out of the wall - one red, one black, one bare copper (all together) and a separate black one.

The new light only has space for three wires. Does anyone know what the extra black wire is for?

Thanks,
Heather

 

[ricicle]

Is this seperate black one in a grey sheath (like the other 3 hopefully are) or is it just one layer of black insulation ?

 

[Heather7000]

Yes, the separate black one is in a grey sheath. And the other three are also in a grey sheath.

 

[ban-all-sheds]

Could be permanent and switched lives.

Use your multimeter to find out what each one does.

 

[sparkwright]

How were the wires connected before?

Were they connected to an old light?
Or in a connector block strip?

Which wires, if any, were joined together?

 

[RF Lighting]

Does each of the black wires have it's own individual grey sheath, and the red and bare copper wire have a grey sheath round the two of them together?

 

[Heather7000]

The wires were connected to an old light before but I don't know how it was wired.

The red, black and copper are all in a grey sheath together. The extra black wire is in a separate grey sheath on its own.

Thanks

 

[ban-all-sheds]

The wires were connected to an old light before but I don't know how it was wired.

If you didn't remove it how do you know it was a light?

The red, black and copper are all in a grey sheath together. The extra black wire is in a separate grey sheath on its own.

Use your multimeter to identify things.

If your response is "I don't have one" then you're in the same class as someone saying "I can't undo this screw because I don't have a screwdriver", or "I can't cut this wood because I don't have a saw", or "I can't knock this nail in because I don't have a hammer".

A multimeter is an essential tool.

 

[ricicle]

Who removed the old light ?

 

[Terry2sheds]

Is it possible that the light was switched from 2 different locations in the house?
OR possibly a switch and a timer?

 

[aptsys]

It was possibly a PIR fitting with switched override.

 

[Terry2sheds]

Yes, in which case, it has a switched and a permanent live as BAS stated earlier in the thread.
If you haven't got a multimeter, perhaps you have a lamp on a wire ( perhaps from a ceiling rose ) that you could use as a test lamp?

 

[Heather7000]

Thanks for your replies.

The previous light was a PIR light but appears to only have one switch in the kitchen.

How do I use my multimeter to find out what the wires are?

If it does have switched and permanent live, where do the wires go in my new light (which is also PIR but only has space for 3 wires).

Thanks

 

[ricicle]

If the new light only has 3 connections then it possibly is of the type where to overide you switch it off and back on quickly. How are the wires terminated at the moment ?
You will carefully have to find out which is the permanent Line, Neutral and Earth. The (presumably) switched Line will have to be terminated seperately in it's own block.

If you are in any doubt about how to safely go about this then I suggest you leave it to a professional.

 

[Heather7000]

Thanks ricicle,

We have tried connecting the light without the extra black wire but it doesn't work.

The light works when wired up to a plug and plugged in so there is no fault in the light itself.

Thanks,