Another Rewiring Question

artha

There are a couple of current(no pun intended)threads already on rewiring but I have a slightly different question.

My house was built in 1963 but has(modern) grey pvc cabling(original as far as I know). We had an extension added 10 years ago with the old fuse board replaced by new consumer unit(Hager) added to accommodate the extra circuits. The sub contract electrician who did the wiring commented that there was no earth on the original lighting circuits so he had added in earths to the old circuits where he could during the new wiring. Apart from the lighting earth problem he didn't think there was likely to be anything wrong with the original wiring although he never did any tests or inspection.

With 10 years having passed and seeing the number of people having rewires done on much younger houses I am starting to wonder whether I need any rewiring. My questions are therefore:

1 Does modern pvc sheathed wiring have an industry recognised finite lifetime?

2 Is there a recognised test that can be done by an electrician to determine the integrity and therefore safety of the existing wiring? (or is it based on visual inspection and therefore a subjective view)

Yorkie1

A friend has just had his electrician do a resistance test, I think he said it was called, on the wiring circuits in his house (wiring is at least 20 years old and probably quite a few years more than that). If brand new wiring has a score of 300, old wiring degrades gradually and I think will be 'failed' at 1. If I understood my friend correctly, the risk is that the wiring is less well insulated and thus could heat up - eventually with a fire risk. His wiring in one circuit was down to 15 so OK for now but they may well get that replaced soonish.

One circuit registered 0.something - that was down to faulty installation in the socket itself, with quite a lot of exposed wire left by whoever put it in. he mended it and the reading went back up to a fine level.

jim_walton

Hi, PVC twin and earth wire lasts indefinitely....You can have your wiring inspected and tested by any IEE registered electrician...

artha

jim_walton wrote: »

Hi, PVC twin and earth wire lasts indefinitely....You can have your wiring inspected and tested by any IEE registered electrician...

Thanks for that. So that leads to another question on rewiring. General advice seems to be that if your house is more than say 30 years old it is likely to require a rewire. What is that guideline based on and is it just scaremongering by the industry to generate work?

macman

artha wrote: »

Thanks for that. So that leads to another question on rewiring. General advice seems to be that if your house is more than say 30 years old it is likely to require a rewire. What is that guideline based on and is it just scaremongering by the industry to generate work?

I would have thought that an advised 30 year rewire period is more due to the vastly higher level of electrical appliances in the typical home in 2010 than in 1980, and the consequently higher load-not necessarily due to deterioration of the actual cabling.
A house wired in 1980 is not going to have any RCD protection for starters, and will probably have trailing extension leads used in the absence of sufficient sockets for modern requirements.
A proper inspection and test would determine what is needed, and if there is any physical deterioration of the cabling.