Old and New Wiring

Uptomischief · Posted: Wed Jul 28, 2004 4:00 pm Post Subject: Old and New Wiring

Hi

I am renovating an old apartment (1970's) whose walls floors and ceilings are all poured concrete, making access to wiring next to impossible. I have three radial socket circuits, one for each room, all with 20Amp fuses but using old red and black wiring (not sure of the size/rating). Can I connect the required 2.5mm wiring where they enter the room and rewire from there, or do I need to tear down to whole apartment and replace the 5m of old wire which connects to the cu.

Any advice would be appreciated

AdamW · Posted: Wed Jul 28, 2004 4:07 pm Post Subject:

I believe the issue with old wiring is that the insulation breaks down rather than anything else. Provided the insulation is doing its job within current tolerances then it is OK to leave it, I think.

There is, however, the issue of where you connect to the old cable. If this is done at an accessible point such as a plug socket or junction box then it is ok. What you can't do is use a standard junction box and then bury that in the wall.

plugwash · Posted: Wed Jul 28, 2004 4:43 pm Post Subject:

all house wiring cable was red/black until very recently (liek the last year or so we are now in a 2 year transito period to new colors)

the fact you thought that red/black meant old obviously means you know very little about household electrics

ban-all-sheds · Posted: Wed Jul 28, 2004 5:22 pm Post Subject: Re: Old and New Wiring

I can't work out what you want to do, and why..

Quote:

Can I connect the required 2.5mm wiring where they enter the room and rewire from there, or do I need to tear down to whole apartment and replace the 5m of old wire which connects to the cu.

If you think that the place needs rewiring, why are you thinking about only replacing part of each cable?

If you don't think it needs rewiring, what is it that you want to do to the circuits?

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TexMex · Posted: Wed Jul 28, 2004 6:23 pm Post Subject:

Out of curiosity. Does anyone know what the anticipated life span is for T&E? (Assuming it is installed and used within spec.).

breezer · Posted: Wed Jul 28, 2004 6:31 pm Post Subject:

allegedly 25-30 years

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murraysnudge · Posted: Wed Jul 28, 2004 6:47 pm Post Subject:

Where do you get that one from breezer, or are you referring to rubber cable?

breezer · Posted: Wed Jul 28, 2004 6:58 pm Post Subject:

its not in writng

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plugwash · Posted: Wed Jul 28, 2004 7:41 pm Post Subject:

i don't think anyone really knows

reccomended policy is to inspect every 10 years and replace if it fails insulation resistance

AdamW · Posted: Wed Jul 28, 2004 11:21 pm Post Subject:

So basically, to sum up, there is no point in replacing all except the last few metres of cable. Might as well do the lot.

Run some extra cables for other stuff whilst you are at it... a network, perhaps (I still don't trust these new fangled, slow, wireless systems.

)

securespark · Posted: Wed Jul 28, 2004 11:36 pm Post Subject:

You call 70's old!!??

In theory, pvc T & E has a lifespan of 30-35 years, but having said that, VIR is very much still alive, and in some cases, well in many houses, having been installed in the fifties.

So, judging by that, I reckon that pvc will outlive rubber, but who knows?

70's should be OK - pvc and solid conductors, but if you have stranded conductors then you may need a full rewire, especially as a lot of 60's cable was not pvc, but ashathene. not sure of spelling.

Uptomischief · Posted: Thu Jul 29, 2004 10:25 am Post Subject:

Thanks for all your input!!

Plug - I neglected to mention I was living in Ireland where I believe the wiring was changed years ago. Not 100% sure when......

Ban - The existing wiring for the sockets was all over the place, so I basically want to relocate and add sockets to each ring circuit. The easiest way to do this would be to completely rewire all the sockets. However, the wiring from the CU to the first socket was buried in the wall and I was wondering if I could use this existing wire from the CU to the first socket and then new wire for the rest of the sockets!! - Hope that makes sense, though I think Adam worked it out first time

Cheers lads!

plugwash · Posted: Thu Jul 29, 2004 4:40 pm Post Subject:

if the cable is pvc and not rubber then it should be ok (though it may be an idea to get it tested)

also i don't know what the irish regs are on marking the intersection between old and new colors. i think there are some irsih sparkys here who culd advise more on this