Dave Plowman (News) wrote:
!

If he did have some 'lying around' it still makes it so old it should
be
replaced. I've never seen PVC twin cable with no earth.


But see Andy Wade's response to another thread about the life of PVC
T&E as follows:

"How about a technical justification for not replacing it? There's an
interesting article on cable life on the IEE web site - he
http://www.iee.org/Publish/WireRegs/...pdateApr04.pdf.

Basically the life is highly temperature dependent (Arrhenius equation,

etc.) If you take the equation in the IEE paper, with the constants
given for PVC, and massage it slightly to give the life directly in
years you get:


life in years = exp(15028/T - 40.678)


where T is the absolute (kelvin) conductor temperature of the cable.


Substituting some temperatures:


- at 70 deg. C (343 K) the life is 22.6 years (as per the paper);


- at 60 deg. C the life is 84 years;


- at 40 deg. C the life is 1,498 years!


70 deg. C corresponds, in principle, to operation at the full rated
current. Except for cables feeding space heating installations,
domestic wiring will spend the vast majority of its life at little more
than ambient temperature."

CRB