Domestic Rewires - When

[Electricalserv]

I'm currently producing a business plan and I need some figures and time scales......

According to GN3 all domestic premises should be Inspected and Tested every 10 years. So when is an installation likely to be issued with a rewire due to deterioration of cables etc. I know it is impossible to say but can we put a ball park figure on this?

 

[PC Electrics]

There's no reason why a good installation with modern PVC cables shouldn't have an expected life of over 100 years. Within this time one would expect to replace accessories.

The main cause of deterioration of cables (other than damage due to poor installation or during service) is the thermal cycling as loads vary. In domestic, cables aren't generally subject to environmental stress.
So, if a house only has one sockets and one lights circuit, the cables may only last 50 years. With more circuits lightening the load on the cables (and now the use of low energy lighting) the cables will see less thermal cycling and so their life will be considerably extended.

As with all things however, there are many individual factors which will contribute to the expected lifetime.

 

[somersetsparks]

Well PVC was supposed to last the life of the building, however some of the earlier PVC suffered from the dread 'Green Goo' reaction.
I would say the most likely cause of needing a rewire is - Lack of sockets, Lack of circuits and lots of alterations.

In general any pvc I have tested on IR etc. has not detiorated. This includes singles from the 60's etc which are now 50 years old and in heavyish daily use.