Rewiring

[john walker]

Hi!, how often should house wiring be replaced when using plastic covered cable. I know it used to be 20 yrs with rubber

[rrh]

I have given up trying to find the recommended maximum service life of standard PVC-sheathed cable under good conditions. Probably longer than the period after which you'd expect to rip everything out and rewire, but that's not the point. The info must be out there somewhere!

[Dave Plowman (News)]

PVC if not exposed to sunshine or overheated etc seems to have a longer life than it's been around yet. I recently removed a bit of (dead) 7/.029 PVC from the depths of my cellar and that was in perfect condition. Would be 40 years old or so.

So an old installation is likely to need replacing for other reasons than the cable becoming unsafe.

[David Hansen]

On Sun, 28 Jan 2007 17:11:22 +0800 someone who may be "john walker" wrote this:-

It shouldn't. In most situations the condition should be monitored and rewiring undertaken when necessary.

[gort]

We probaly have not reached the time yet, considering pvc coated cable started to be in fairly widespread use around the sixties .

Dave

[The Natural Philosopher]

Oh dear. How ever did me mums house survive 50 years with its original rubber cable?

In general woiring will last longer tan its useful for..I have never heard of degrade PVC wiring being found unless in the sun or near polystyrene..

It's got to be at lest 50 years life for the old stuff put in the the late 50s' ..

Most houses tend to go through modest refurbs every 30 years and major ones every 50-60. I doubt many houses exist with wiring much older than

60 years.

[Andrew Gabriel]

PVC cable itself is predicted to have a life of 1000 years at 30C, dropping to 21 years if running continuously at max temperature of

70C. The cable in the first PVC T&E installations is usually found to still be in perfect condition unless some external influence has damaged it.

What does wear out are the wiring accessories such as sockets, switches, lampholders, fuse boxes. These are easy to replace compared with the cable itself, but in an older installation, you may find you don't have enough sockets, circuits, etc for modern requirements. A wiring accessory which is worn out can generate extra heat, which in turn can damage the PVC in the locality. Occational inspections will bring to light accessories which need replacing.

There's also the issue of bringing an installation up to current regs. There's no requirement to do this for its own sake, but if you are working on an installation, you should for example bring the earthing up to current regs.

[mmzz]

Not common but it can deteriorate dangerously, depending on the original design, installation and what load it has carried

[The Natural Philosopher]

That's what some warlord once said as he pounded a castle with his cannon isn't it?