Wire Colour

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Hi

I have just lengthened the live and neutral wires to a ceiling rose and noticed that the blue wire I used was slightly darker in colour to the one I replaced. Can someone please tell me if the rating will be the same, will it be ok for the job, or should I replace with like for like colour.

Thanks in advance :confused:
 
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Another question....... There was no earth wire from the lighting circuit(in the loft) to the ceiling rose, should there be? The new light fitting is all plastic if that makes a difference.

cheers
 
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Is there any earth core in any cables on your lighting circuit?

if not it suggests old wiring. pre 1967 i think. the earth might have been chopped back to the sheath.

you can only fit plastic fittings and switches where no earth core exists.
 
Hi industryspark, there is an earth running round the lighting circuit but it stops at a junction (white block)and blue and brown run down to the ceiling rose.

Cheers
 
Sounds like the wire wasn't long enough so it was extended (using flex??)? What do you mean by white block, chock block? Is this in a suitable enclosure?
 
Hi
The white block..... Is a block connector one wire in one side, screwed in place and one out the other side, except the earth.
 
Yup, sounds like the wire was too short, is there access to above? If so then you may install a junction box. The earth in an ideal world will be continued through using a twin and earth cable. This means the earth wire is present should you ever need to use a metal fitting in the future. If the earth wire is not required, sleeve it and terminate it into a piece of chock block.
 
The earth is on its own, it is not in the same sleeving as the other wires it is in yellow and green sleeving.
I can see what you mean it is there if required... Oh dear, the light fitting before this one was metal and not earthed.


I have another question... while your on. What is the thinnest earth wire available, the reason being I have a reel of earth wire (for supplementary bonding) and I don't know the thickness (label has come off) as as I understand it you need at least 4mm earth to sup bond. Any idea how to measure the thickness?

Thanks
 
cables are measured by the cross sectional area.

if you have a good caliper or a micrometer you can measure each strands diameter and from that calculate its cross sectional area and from that the CSA of the cable as a whole

you could also measure the diameter of the whole bunch but that may not be accurate enough to distinguish between the sizes (due to air gaps non-roundness etc).

another way is to take a small peice to the DIY store and compare it end to end with the cables on the shelves there.

supplementry bonding must be at least 4mm unless it is either part of a cable (where presumablly you would notice if it was inadvertantly damaged) or protected by conduit (trouble with this is what to do at the ends leading to the clamps).
 
Or just show it to any good sparky and they'll say, "oh thats 4mm²" :LOL:
 
Thanks guys
From your replies, I would therefore assume that earth cable does come in a thickness less than 4mm

cheers
 
Yes, you can get it in smaller sizes, the smaller than 4mm² that are available in standard sizes for copper cables are 1mm², 1.5mm², 2.5mm².
 

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