On 18/03/2019 12:02, Graham. wrote:

"Can not use the existing red/black 2.5mm cables because the CPC
is thinner than modern cable"

There was a time when 2.5mm^2 cable had a 1mm^2 CPC. However that was
later changed to 1.5mm^2 (probably anything installed after 1981 should
be ok). So there will still be some old installations out there with the
thinner CPC, but that does not mean *all* red/black installs are like that.

I'm sure it is thinner but is it true it can't be used?

It would be unwise to use it on installations with old BS3036
re-wireable fuses, but on a modern install it will usually be ok
(although one should check by calculation)

I am guessing that the answer depends on whether or not it's a new
circuit.




--
Cheers,

John.

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