Rewiring a 1960's bungalow

[eetsteamleader]

I am looking at rewiring/ adding extra sockets etc to a 1960's bungalow I have just bought.

There is only 1 single socket in each bedroom and I am looking to increase this to about 3 doubles.

The existing wiring is PVC insulated although the earth is not sheathed at the sockets. It is sunken into the wall by plastic or metal channel.

My questions are as follows:

1. Do I need to replace this wiring as it is PVC insulated. What evidence is there that it degrades over 50 years to a point of being unserviceable. I find it hard to understand if this is so as it takes thousands of years to breakdown in landfill sites.

2. If I do replace it. is it possible to pull out the old cables and insert new. any tips on how to do it.

3. For the extra sockets I'm chasing the cable into the wall and threading it through oval conduit. Is 20mm conduit suitable for 2.5T&E & will both cables fit in the one conduit. Is there any tips to pull them through easier.

Any advice would be much appreciated.

 

[RF Lighting]

1. Do I need to replace this wiring as it is PVC insulated. What evidence is there that it degrades over 50 years to a point of being unserviceable. I find it hard to understand if this is so as it takes thousands of years to breakdown in landfill sites.

What size is the CPC in these cables?

Are they definatly PVC, or could they be plastic?

Cables whether old or new can be degraded by UV rays, impact, heat, fauna, water ingress etc. Do the IR tests come back ok?

2. If I do replace it. is it possible to pull out the old cables and insert new. any tips on how to do it.

You can try, but it doesn't always work.

Take care not to damage the cable on the sharp edges of the capping.

Tie the cable onto the old cable. Don't just tape the cables together, as it will come off. It is easier if you have an assistant to feed the cable in straight while you pull on the other end.

3. For the extra sockets I'm chasing the cable into the wall and threading it through oval conduit. Is 20mm conduit suitable for 2.5T&E & will both cables fit in the one conduit. Is there any tips to pull them through easier.

It should just fit.

If things are tight, use some pulling lube such as yellow 77

 

[seasickstevie]

Two 2.5 T&Es in a 20mm oval it too tight in my opinion.

I always put in two separate conduit drops to each socket, or one 25mm if I'm using extra deep boxes with 25mm knock-outs.

And as already mentioned by RF, the CPC is likely to be a smaller size than today's cable if it's more than about twenty years old, so you've got no chance of incorporating it in a new ring final.

 

[ColJack]

now's the time to do it, before you redecorate..

 

[LiamPope]

If your existing installation is only a single socket per room, and you're doing a full rewire, chasing out all over the place for 3-4 times the existing in additional sockets, etc, why on earth would you even consider keeping the little bit of 50yr old cable??? Compared to what you've already got to do, it's so little extra work to rip out the old installation and start completely from scratch and have all the sockets where you want them. I'd feel a bit... dirty doing a shiny new install and leaving that old stuff in there

Liam

 

[ban-all-sheds]

• //www.diynot.com/wiki/electrics:part-p
  
• What are the 3 different types of domestic single-phase supplies provided in this country, how would you recognise them, and what differences do each make to the requirements for the rest of the installation, particularly any outdoor supplies?
  
• How do you propose to isolate your supply so that you can connect up your new CU?
  
• For a circuit to supply a <thing> (doesn't matter what), how would you go about deciding what cable and protective device to use?
  
• Do you understand how the way in which you install cables affects how much current they can carry?
  
• What are the rules concerning cables concealed in walls, partitions and under floors?
  
• Do you know the requirements for main and supplementary bonding of extraneous conductive parts?
  
• Which circuits must be RCD protected?
  
• Explain what tests you would carry out on the installation - please cover the sequence you'd do them in and at what point you would energise the installation, and for each test explain what is being measured, why it is important, how you would carry out the test, and with what equipment, and what sort of results you would expect to get if everything was OK.

 

[RF Lighting]

Would you mind if I added that post to the wiki?

 

[ColJack]

is that the results of your "10 questions to try and scare DIY'ers off doing their own electrics" thread you did a while back?

 

[ban-all-sheds]

 

[ericmark]

is that the results of your "10 questions to try and scare DIY'ers off doing their own electrics" thread you did a while back?

I think BAS has raised some good points in the right manor. There are those who do know how to do all he has listed but many don't.

And unless you are made aware there are formula and tables giving different ratings for cables according to how they are installed it is likely a DIY person will walk into B&Q and see the information given there and think they have selected the correct cable.

Only yesterday I was talking to some friends about Ali-tube cable and was pointing out that electricians who can raise the paperwork required to change a consumer unit will often regard the extra cost as not worth it. But for the DIY man who wants to add one socket and keep to the regulations then Ali-tube cable is the easiest way as he only has to use a RCD socket to comply.

But it is not sold in DIY sheds and there are no notices to tell him about cable buried less than 50mm so in the main the DIY man will do work which does not comply.

For a full rewire the £100 plus vat charge for Part P is not too bad. But when he has finished and council tell him to rip it out and "do it again and do it properly" as any good mother or wife will often demand, it becomes expensive. And I think to tell people what they are letting themselves in for is better than laughing at them after they get it wrong.

Full marks BAS

 

[seasickstevie]

For a full rewire the £100 plus vat charge for Part P is not too bad.

That can be doubled depending on which Council you're under.

 

[ban-all-sheds]

Or more than quadrupled if you've got one of the law-breaking councils who charge you a fee and expect you to commission your own PIR.

 

[Steve]

donny council its £100 or thereabouts for minor works, and £300 or thereabouts for a rewire.

 

[ban-all-sheds]

is that the results of your "10 questions to try and scare DIY'ers off doing their own electrics" thread you did a while back?

It's not designed to scare anyone off, just to find out if the OP understands how much there is to it.

We know he's still around - //www.diynot.com/forums/viewtopic.php?t=184260 but he's not come back and answered any of the questions....