Electrical conduit in walls.
Discussion
dhutch said:
What is the current suggested life expectancy of solid core pvc t&e cable?
25 years seems to be typical.e.g. https://www.whyprysmian.co.uk/cable-design.html
Web said:
A cable’s design life is based on the cable running at maximum load all day every day for 25 years. At maximum load, the cable conductor will be at its maximum temperature, normally either 70℃ or 90℃, depending on the cable’s grade of insulation and it’s BS specification.
If the cable is not fully loaded all of the time then it can be expected to exceed its design life. For example, if the cable is loaded for 8 hours in a day, its life expectancy could be in excess of 40 years.
Then a list of things that could effect life.
So in short, we don't know.... Obviously loading will be reasonably light in most domestic applications. We are using Or for what it's worth. If the cable is not fully loaded all of the time then it can be expected to exceed its design life. For example, if the cable is loaded for 8 hours in a day, its life expectancy could be in excess of 40 years.
Then a list of things that could effect life.
Obviously if it where 25years it would likely need doing while we where still there, and which point conduit would be extremely important to me.
But it re-enforces the issue, that it's likely these cables will be replaced at some point in the future, both in our house and others, so it's not a stupid question.
Daniel
Alucidnation said:
Planning on what might happen in 25 years time to an electrical installation is a bit odd tbh.
An awful lot can and will change in that time.
Granted things change and I don't have a globe, but if anything surely that support using conduit for big drops where within the time we are in the house we might want to re-spec whats going to the light switch? On the flip side the 13amp plug has been around 70 years, as an evolution of the round pin series before it, and while we might totally change our electricity usage we also might not.An awful lot can and will change in that time.
My parents built there house in 1988 and 31 years later its already well past 25years on the same wiring and in the 60's they might get well get to 50 years living in the same house. I am now 31 have just bought what I hope and expect to me mine and my partners family home, so again the 'design brief' where practical is a 50 years life expectancy. As said, the house is 115 years old and there is no reason to presume it wont do another.
Its not like I am talking about going mad, to swap a bit of capping strip for some conduit, in some for the large drops in the big rooms.
Round might be pushing it for clearance, but the '25mm oval' at 28x11x0.8 seems perfect.....? Might raise it with my electrician, he will love me.
Daniel
Pheo said:
It’ll be a lot easier to cap them I suspect in terms of filling the chase.
If you are really sure you’re going to go in again then I guess use conduit. But if you’re doing that how likely you’re going to be redecorating anyway so running in some new wires wouldn’t be that disruptive
Really hard to know isn't it. If you are really sure you’re going to go in again then I guess use conduit. But if you’re doing that how likely you’re going to be redecorating anyway so running in some new wires wouldn’t be that disruptive
Hard to know what might change or how long these cables will last. Obviously the room will be redecorated again but I'm hoping having replaced the linning paper future redecorating would just be a repaint.
Obviously there is an afternoons work in fitting the conduit but it shouldn't be much/any harder to plaster over should it?
Daniel
Well, plasterer is due today (i'm at work) so its all about the buried in a renovating lime and cement mix for all eternity.
I did buy some 25mm oval, it was much easier to get a pair of twin and earth down than the electrician suggested as while you have to get the kinks out is did just slide in in one hit. I could get the top end up behind the plaster moulding away from any risk of plaster getting down the tube, and in several cases I managed to get it though the ceiling up behind the first floor skirting. Obviously at the box end you could bring it down to the round grommet and while you wont be able to pull the cable past there without changing the box it does save 7 1/2 foot of chase all the way down the wall.
The downside is however in a couple of places the way its been run with sockets on the other side of the wall, there is a continuous loop of cable and I didnt have time to cut it on the far side, pull through, and feed back, one of the power cables also goes though mid-wall into the room with the cu. The two lighting chases would need 2x25mm to get them down and the case wasnt wide enough and I didnt have time to widen it. Two of them I changed and then when adding the speaker cables the electrician changed it back to capping because that can fit 2x2.5 1x.15 and a Cat6 where the conduit can't.
Obviously I know the cables will likely last 50 years, by which time I will be 82, and if they do another ten from there its unlikely to be my problem, and someone can always chase it out again, but its also just seems a shame that everything seems to be about cutting costs as long as its ok for now, nobody does a rolls-royce job even if thats what you ask them for. The original spec-sheet requesting the work say 'conduit to be used where practical, to allow cables to be replaced' but along with clipping cables in the loft thats just been forgotten in the interest of speed and cost.
Heyho, either I am mad, or the world cant be arsed to do it nicely. Roll on f
king up the eu and polluting out planet with single us plastics.
Daniel
I did buy some 25mm oval, it was much easier to get a pair of twin and earth down than the electrician suggested as while you have to get the kinks out is did just slide in in one hit. I could get the top end up behind the plaster moulding away from any risk of plaster getting down the tube, and in several cases I managed to get it though the ceiling up behind the first floor skirting. Obviously at the box end you could bring it down to the round grommet and while you wont be able to pull the cable past there without changing the box it does save 7 1/2 foot of chase all the way down the wall.
The downside is however in a couple of places the way its been run with sockets on the other side of the wall, there is a continuous loop of cable and I didnt have time to cut it on the far side, pull through, and feed back, one of the power cables also goes though mid-wall into the room with the cu. The two lighting chases would need 2x25mm to get them down and the case wasnt wide enough and I didnt have time to widen it. Two of them I changed and then when adding the speaker cables the electrician changed it back to capping because that can fit 2x2.5 1x.15 and a Cat6 where the conduit can't.
Obviously I know the cables will likely last 50 years, by which time I will be 82, and if they do another ten from there its unlikely to be my problem, and someone can always chase it out again, but its also just seems a shame that everything seems to be about cutting costs as long as its ok for now, nobody does a rolls-royce job even if thats what you ask them for. The original spec-sheet requesting the work say 'conduit to be used where practical, to allow cables to be replaced' but along with clipping cables in the loft thats just been forgotten in the interest of speed and cost.
Heyho, either I am mad, or the world cant be arsed to do it nicely. Roll on f
king up the eu and polluting out planet with single us plastics.Daniel
I actually do know what you mean and it annoys me when stuff is done to a "that'll do" standard. In my house the cables where run loose under the floors then brought up to the sockets and the drops have been chased to about 10mm deep, T&E clipped to the brickwork and then covered in crap and the light switches are all terminated into 16mm back boxes. ALL of which need to be changed if you want a light switch that isn't from poundland. No capping let alone conduit!
Amusingly in the loft everything is beautifully clipped and aligned and all the terminals, CU and cable dressing is spot on. I suspect the house basher did the cable runs that he knew wouldn't be seen and a sparky came along later and connected everything up. Even the old rubber sheathed crap that has been isolated is flapping about loose under the floors and loft so none of that was done properly back in the old days which we assume was a time tradesmen gave a damn. Main thing is though that it does actually work, it's safe, has passed all the tests and most people will never even see it let alone give a st if a bit of cable has been clipped at 250mm intervals. A sparky isn't going to start buggering around with some ancient (by then) conduit in 50 years time I wouldn't have thought.
The cheapest, fastest job was done on my house 10 years ago and I suspect it will be again in 20 years time when I'm gone. Spend a day on site watching how hotel rooms are put together and you wont worry too much about the disposable nature of your own house
Amusingly in the loft everything is beautifully clipped and aligned and all the terminals, CU and cable dressing is spot on. I suspect the house basher did the cable runs that he knew wouldn't be seen and a sparky came along later and connected everything up. Even the old rubber sheathed crap that has been isolated is flapping about loose under the floors and loft so none of that was done properly back in the old days which we assume was a time tradesmen gave a damn. Main thing is though that it does actually work, it's safe, has passed all the tests and most people will never even see it let alone give a s
t if a bit of cable has been clipped at 250mm intervals. A sparky isn't going to start buggering around with some ancient (by then) conduit in 50 years time I wouldn't have thought. The cheapest, fastest job was done on my house 10 years ago and I suspect it will be again in 20 years time when I'm gone. Spend a day on site watching how hotel rooms are put together and you wont worry too much about the disposable nature of your own house
Edited by StoatInACoat on Thursday 24th January 09:01
Yeah, its a right mixed bag. Annoying but not the end of the world.
My last house was a 1938 council build, solidly built and a cracking house, but years of low budget work, badly dot & dabbed, patched this, re-done that, and I largely carried on the same. Replace what needed and keep the rest.
Slight difference here for me in a way is that this is a largely original and reasonably un-molested 115 year old Edwardian build, bar being split into two semis and re-wired in 1965 and the bay windows being replaced 30years ago. So while it is a very long way from a conservation project I do feel some obligation not to bugger it up too much during my tenanture. The first owners did 65years between further and son, the last owners 35 years, and we plan another long spell.
Daniel
My last house was a 1938 council build, solidly built and a cracking house, but years of low budget work, badly dot & dabbed, patched this, re-done that, and I largely carried on the same. Replace what needed and keep the rest.
Slight difference here for me in a way is that this is a largely original and reasonably un-molested 115 year old Edwardian build, bar being split into two semis and re-wired in 1965 and the bay windows being replaced 30years ago. So while it is a very long way from a conservation project I do feel some obligation not to bugger it up too much during my tenanture. The first owners did 65years between further and son, the last owners 35 years, and we plan another long spell.
Daniel
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