Wiring in 17th C Timber framed house - for dummies

[Jellyfire]

I've been following the other thread and I'm afraid it's drifted way beyond the realms of my understanding, could somebody help me pin down what I need for the fairly simple rewiring I need to do..

We have RCD switches in the 2 fuseboxes, all the cables are external in grey plastic sleeve, and there are round junction boxes which have various wall lights, sockets etc coming off them.

What I would like to do, as I'm replastering, is replace all the wall lights, light switches and power sockets, and chase these cables into the walls. I'll be leaving the main ones exposed as they are. So all I need to do is replace each cable (spur?) that leads to a light etc, with a longer one which I can then bury in the wall. We are having wall lights made by a local blacksmith (infinitely cheaper than jim Lawrence etc, and quality is superb), but they won't have the fittings in them, in effect they are a piece of iron tube with the cable through and the light fitting screwed into one end.

So my questions are:
What kind of cable do I need to buy?
What kind of conduit should I buy for burying in a daub wall, it will all be finished in a lime plaster skim
What should I google to find the light fittings, all I can seem to find are actual wall lights, I just need the bulb holder bit and cable

 

[Baron de Gynes]

Really can't help with any of the technical questions, but I've just done a google search for 'bayonet bulb holder' and it came up with quite a few sites including this one which may be of some help.

 

[Lime]

I've been following the other thread and I'm afraid it's drifted way beyond the realms of my understanding, could somebody help me pin down what I need for the fairly simple rewiring I need to do..

We have RCD switches in the 2 fuseboxes, all the cables are external in grey plastic sleeve, and there are round junction boxes which have various wall lights, sockets etc coming off them.

What I would like to do, as I'm replastering, is replace all the wall lights, light switches and power sockets, and chase these cables into the walls. I'll be leaving the main ones exposed as they are. So all I need to do is replace each cable (spur?) that leads to a light etc, with a longer one which I can then bury in the wall. We are having wall lights made by a local blacksmith (infinitely cheaper than jim Lawrence etc, and quality is superb), but they won't have the fittings in them, in effect they are a piece of iron tube with the cable through and the light fitting screwed into one end.

So my questions are:
What kind of cable do I need to buy?
What kind of conduit should I buy for burying in a daub wall, it will all be finished in a lime plaster skim
What should I google to find the light fittings, all I can seem to find are actual wall lights, I just need the bulb holder bit and cable

There are quite a few aspects of your post that demand a reply.
First off, I don't think you should be not doing this if you do not understand the previous discussions.
(said with care not disdain)
Why?
Because the major alterations you wish to do yourself require building regulation approval.
The old wiring you are changing has to be installed to modern standards and your main earthing system needs to be checked.
The fittings you have had made need to comply with the regulations concerning earthing etc.
I could list more reasons.

I have seen far too many unsafe home-installed circuits and light fittings in my time to let this post go by.
The lights may work but that does not mean they are safe.
Think of the consequences if something horrible were to happen.

 

[Jellyfire]

Pah, what's the worst that could happen? .... Oh, ok quite a lot I guess!

I didn't realise it was that big a deal as I was essentially just replacing one light fitting with another, but if you'd recommend leaving it to an electrician then will take that on board and leave it to a professional

 

[Lime]

I have a lot of sympathy for your situation.
However the presumption that the existing wiring is safe could be misplaced.
viz:

I didn't realise it was that big a deal as I was essentially just replacing one light fitting with another

Old wiring installations often left a lot to be desired with regard to adequate earthing and safety.
Moving and altering cable and connections is likely to create further hazards.
At best, judging from your description, it is likely that the wiring does not comply with modern regulations.

What concerns me in particular:
The existing earthing arrangement may be inadequate, faulty or non-existent.
To replace the cables the junction boxes need to be accessed and connections altered.
~The wiring in junction boxes is often complicated and requires skill, knowledge and competent judgement to understand how the circuit is constructed and if it is still satisfactory.
~The juction boxes were often inadequate to meet present day standards and demands particularly for safety.
The wiring of the metal light fittings needs to be done so they they are safe and remain safe in use.
~That demands electrical understand and mechanical engineering skill.

I'm sorry to be such a wet blanket but electricity can be very dangerous if not wired up correctly.

 

[Flyfisher]

Lime makes some good points and I tend to agree; if someone isn't confident about such things then it's wise to get professional advice. It's why I won't touch gas installations, even before it became actually illegal.

But it might be worth considering a 'middle way'. Carefully research the intended work, DIY and then get a professional electrician to inspect and certify the work.

This is what I did when rewiring part of our house. I installed all the circuits and led the wiring back to the old CU and the electrician then installed a modern CU, connected all the new circuits and tested everything is compliant and safe - and I have the certificate to prove it.

I'd accept that for a small job it might be just as cost-effective to let the electrician to the whole job, but for large jobs with awkward access and cable runs it can save a lot of money.

Just a thought.

 

[MdB]

As the others have said, you need expert advice or an expert to do the work. There are lots of issues which aren't immediately obvious like cable thickness. There is no rule of thumb, it needs to be worked depending on length, bundling with other wire, installation method etc.

As FF says, I would see if you can find a friendly electrician who is willing to tell you where and how to fit the wires. He can then connect up and test once you have done this.

 

[Lime]

It's why I won't touch gas installations, even before it became actually illegal.

This comes as a surprise to most people but it is not illegal to service your own gas fittings.
What is illegal is servicing gas fittings for a profit if unqualified to do so.
i.e. as a business.

If a householder is competent to do the work and actually does competent work it is legal.

 

[Jellyfire]

Sorry for not replying earlier, all my power had gone off so no Internet, it's sparked a bit and is working again now though. :?

Good tips Flyfisher, MDB, I might just make the channels for the cables in the walls and then get a sparky to do the actual connection, probably not worth the risk given my lack of knowledge of electrickery, as per Limes advice

 

[tobydog]

We've had four different electricans work on our house in three years. We have now found a father and son team who we are very pleased with. During our extension and renovation work we had to get all the electrics signed off by a competent person before we could get the building regs sign off. 12 months later we decided to move some electrics around and this included taking out the installed strip light in the inglenook and replacing it with a double socket for lamps. It didn't take long for all the wrong reasons. The light was already wired into the separate socket circuit :shock: . If you don't know your wiring, please turn everything off and not just isolate.

 

[Flyfisher]

It's why I won't touch gas installations, even before it became actually illegal.

This comes as a surprise to most people but it is not illegal to service your own gas fittings.
What is illegal is servicing gas fittings for a profit if unqualified to do so.
i.e. as a business.

If a householder is competent to do the work and actually does competent work it is legal.

That's interesting, but it still won't persuade me to work with gas. :wink:

 

[Flyfisher]

Good tips Flyfisher, MDB, I might just make the channels for the cables in the walls and then get a sparky to do the actual connection, probably not worth the risk given my lack of knowledge of electrickery, as per Limes advice

It has always seemed to me that the time-consuming, and therefore costly, part of 'electrical' work is indeed all the channelling and cable routing, so there is significant money to be saved if you have the time to DIY. Plus the added advantage that you will probably be more concerned about the fabric of the house than, perhaps, an electrician on a tight schedule (no offence zebra). So, coupled with a professional electrician to do the final connections and certification such works need not be vastly expensive or unsafe.

 

[Lime]

Make-safe is the first rule of electrical rewiring.
You cannot rely on a switch turned off.
You must test for no voltage present every time work is started.

Sometimes a switch will physically turn off but not electrically disconnect properly and the wiring may be all live, neutrals included.
Relying on the lights going off is not enough.

 

[Flyfisher]

If you don't know your wiring, please turn everything off and not just isolate.

. . . And even if you do know your wiring and can isolate the correct circuit it's still a good idea to verify the circuit is dead. Professional electricians working on large systems with lots of work in progress will actually physically lockout the circuit they are working on! To avoid the possibility of someone else accidentally switching things back on while they are working on something. You can't be too paranoid about such things, in my view!

Edit for the clash with Lime's post - though such things can't really be over-stressed!

 

[Feltwell]

The "paranoid" approach to mains testing has always seemed the best one to me!

I've got a cheaper version of one of these voltage detector pens, which is really useful - put the tip against a cable and it beeps if it's live. A great help when you find mystery cables but they're not foolproof though - always take the approach that if it beeps then it's live, if it doesn't beep then it *might* be live and still needs treating with caution.

http://www.screwfix.com/p/megger-vf1-vf2-vf-ac-voltage-detector-pen/23932

Mine does occasionally beep with dead cables, I think it depends on if that dead cable is ran alongside a live one further back up the run. I've yet to find an occasion when it doesn't beep with a live cable, but I'm not keen to be the first one to find that out the hard way!

It's a good initial guide but I always do a final check with a multi-meter on the cores, and I only expose the cores after switching the power off. It is good as a final check that something is dead after you've switched the power off, just to be 100% sure.

 

[MdB]

I might just make the channels for the cables in the walls and then get a sparky to do the actual connection

Make sure you speak to the sparky before making the channels. There is a right and a wrong place (as well as depth) and there are rules about making holes in beams as well.

 

[Zebra]

This is what I did when rewiring part of our house. I installed all the circuits and led the wiring back to the old CU and the electrician then installed a modern CU, connected all the new circuits and tested everything is compliant and safe - and I have the certificate to prove it.

Just out of interest Flyfisher, presumbly the electrician signed off on the certificate to say that he was responsible for the design, construction and inspection/testing? The form will have used those three phrases. If he didn't actually construct the installation - you did - then there's a lie on the certificate, and a very muddy liability issue if something were to be wrong with the job! Plus it's not strictly speaking legal. I think a spark would be mad to sign off someone else's work as their own for just that reason, and I certainly don't do it! If you have a good enough relationship with your electrician that he trusts you to do a job that he will put his name to, then I'd think you're lucky, but I wonder if it's perhaps not something to be encouraged......

 

[Flyfisher]

That's a very fair point and some more detail might be helpful.

Our house is quite large and I've been tackling it in various stages. The first stage was to get the 'new' part (18th century) habitable and, among other things, this involved a complete re-wire. All of this work was done by my now-friendly electrician. and it also involved a completely new supply arrangement to the entire house, replacing twin overhead supplies on different phases to a single underground one.

During this work we obviously discussed the job in detail and also my plans for the remainder of the house. Before I started on 'phase 2' (of many!) the electrician came out and we discussed what I planned to do, the cable routings, circuit details etc. The work involved a couple of ring circuits, a cooker supply and one lighting circuit. So I think it's fair to say the electrician was in on the design.

I then did the installation work as we had discussed and then called him back to connect everything into the CU. As planned, he replaced the old CU with the new one I described in a previous post. At this stage of the job, all my wiring was still visible and easy to verify. It was effectively as if I was his apprentice, except that he wasn't on site with me everyday, but he was able to see and verify all my work before testing and certifying the overall system.

So I think it's fair to say (indeed, for him to say) that he was responsible for the design, construction, inspection and testing and it was just that he "subcontracted" most of the physical construction to me - and as we all know, it's the physical construction work that takes most of the time, which is where the DIYer can benefit without compromising any safety issues.

I do, however, take your point that it's not quite as simple as DIYing a complete new installation and then finding someone willing to drop in out of the blue and certify everything. It all has to be discussed and planned in advance.

 

[Zebra]

Well yes I see your point, and can see that in those circumstances he might well have been happy to do what he did. I guess there are a whole range of possible scenarios in the situation we're talking about, from one where, as you describe, the electrician is able to fully inspect your work and is responsible at every stage, to one where, as you say, someone DIYs a complete new installation and then tries to find an electrician willing to drop in out of the blue and certify everything. I suppose it's the latter that I was meaning to discourage. However, the scenario you had with your electrician is one I would be wary of entering into with a customer, unless I knew them very well and trusted their workmanship! I have done something similar only once, with my sister, where I first-fixed her house, she second-fixed, and I tested and did all the consumer unit, and issued the certificate as if it were all my own work, but that's my sister, and I trust her workmanship absolutely!

 

[Feltwell]

I don't blame you at all for being cautious about what you sign off Zebra, I'd be the same.

With my garage I did first and second fix and ran the SWA cable back to the incoming supply in the cellar of my house. An electrican did the connection to the supply and tested the whole installation, and gave me certification that said that he had tested circuits that I had installed. He was a bit hesitant at first to do the job but was happy once he'd seen what I'd done.

I'm glad I got a professional electrican to inspect it all - if nothing else because his test equipment revealed that the main incoming RCD switch in my (new) garage consumer unit had too much resistance and had some kind of fault. Luckily I had a spare, higher rated switch that we could fit instead.

The Building Inspector was happy just to take the NICEIC certificate that said that one or more circuits had been installed at the house, no detail at all.