Andrew Gabriel coughed up some electrons that declared:

In article ,
Tim S writes:
I've just cut off and made safe a bit of T+E dangling between the trees,
feeding some gate lights.

I would estimate it to be about 10-15 years old. It wasn't brittle but
the sheath was noticably harder than it should have been. Don't know how
much longer it would be before it became dangerously hardend, but it was
well on its way.

The PVC round conduit on the last leg to the bulkhead fittings shattered
when I touched it with the strimmer cord (hence the urgency in
disconnecting the circuit) - that was very very brittle.

So yes, sunlight does very much affect PVC, from first hand experience.

I've known a number of lengths of PVC T&E exposed to sunlight,
some of them older than me and dating back almost to the introduction
of PVC wiring. None have deteriorated noticably (unlike me).


Wonder why the variance?...

My PVC was white, whatever difference that might make...