I'm inclined to agree- the enemy of modern plastic cables is overload or damage. In that sense the cable life is often determined by the user,  if extra loads are added, or the cable is painted over with creasote or nailed through or similar. 

Cables that run cool, away from rodents and UV light may last for several centuries - in practice, like bricks,  for the life of the building. (or until the building is re-purposed)

Junctions are probably a weaker spot.


Wiring in cars has a shorter life, as it current ratings are determined based on a higher copper temperature (105C in some cases), but this does not matter, as cars do not last that long.

On the current track record it is quite possible that future generations will come and marvel at 20th century wiring much as we admire old cathedrals and so on, and say "you'd never get craftsmanship like that now"!  in awed voices while  looking up at the basket tray and twin and earth across the warehouse ceiling . Well, maybe not that last bit.


Some early plastic compositions were not as stable as today, so it is certainly worth looking at the cores for signs of  decomposition, especially with cables that pre-date the 1970s. There are some that have a 'green goo' failure mode where the plasticiser leaks out and corrodes the copper.

I'm inclined to agree- the enemy of modern plastic cables is overload or damage. In that sense the cable life is often determined by the user,  if extra loads are added, or the cable is painted over with creasote or nailed through or similar. 

Cables that run cool, away from rodents and UV light may last for several centuries - in practice, like bricks,  for the life of the building. (or until the building is re-purposed)

Junctions are probably a weaker spot.


Wiring in cars has a shorter life, as it current ratings are determined based on a higher copper temperature (105C in some cases), but this does not matter, as cars do not last that long.

On the current track record it is quite possible that future generations will come and marvel at 20th century wiring much as we admire old cathedrals and so on, and say "you'd never get craftsmanship like that now"!  in awed voices while  looking up at the basket tray and twin and earth across the warehouse ceiling . Well, maybe not that last bit.


Some early plastic compositions were not as stable as today, so it is certainly worth looking at the cores for signs of  decomposition, especially with cables that pre-date the 1970s. There are some that have a 'green goo' failure mode where the plasticiser leaks out and corrodes the copper.