Just bought a house.Needs a rewire.....but.

[PBSCO]

Just bought our first house,got a good deal as it needs loads and loads of work doing to it.
First thing first,had a look at electrics and wondered why any 3 bed house would need about 25 sockets in just the lounge and dining room.
Turned power off and traced what I thought was a ring main to the back door where it stops.

So I am guessing 25 sockets on a radial is not particularly good?

Stripped everything back and just left a double in each room for now.

Plan is to run a new ring for the lounge,dinning room and hall. Another for the Kitchen and another for the top floor and maybe another for the loft but no rush for that yet....Is this the best way to do the rewire.

Planning to get all the cable in while I have access to walls and under floors(when the boss tells me where she wants sockets) and leave a loop for each socket to be wired up and a meter tail where new CU is going.

Got a house warming present from an old mate.Prysmian 6242B Twin & Earth Cable 2.5mm x 100m .....is this suitable for my new ring main??

What size cable should I be using for the lighting????same as above but 1.5mm

Thanks for any replies

 

[OwainDIYer]

nothing wrong with 25 sockets on a ring or a radial, depends on the anticipated use - which is usually covered by the floor area recommendations. The electricity doesn't fall out of them if there's nothing plugged in.

If I got rid of 4-way strips I'd need about 20 sockets in my lounge.

And you install plenty everywhere because The Management will change her mind where she wants them once you've finished plastering anyway.

 

[PrenticeBoyofDerry]

Best to do rewire whilst house is in bits.
So wise to do it now.
The fact that you don' t know or have doubts what is the best sized cable to use on a RFC makes me think you need to get yourself informed on circuit design and the requirements of BS7671 and also the relevant building regulations.
I personally would have
RFCs for up and down
Then radials for kitchen (cooker/hob circuit, under worktop appliance and above worktop appliances).
The loading and length of the lighting circuits would be key to choice between 1.00mm and 1.5mm.
Also if it's DIY you will need to notify building controls prior to starting work.

 

[17thman]

Best to do rewire whilst house is in bits.
So wise to do it now.
The fact that you don' t know or have doubts what is the best sized cable to use on a RFC makes me think you need to get yourself informed on circuit design and the requirements of BS7671 and also the relevant building regulations.
I personally would have
RFCs for up and down
Then radials for kitchen (cooker/hob circuit, under worktop appliance and above worktop appliances).
The loading and length of the lighting circuits would be key to choice between 1.00mm and 1.5mm.
Also if it's DIY you will need to notify building controls prior to starting work.

whats the rationale behind rfc on up and down?

 

[EFLImpudence]

Because no one can tell if you mean Ring or Radial.

 

[ban-all-sheds]

So I am guessing ... Is this the best way to do the rewire ... is this suitable for my new ring main?? ... What size cable should I be using for the lighting????

PBSCO - asking questions like that shows, beyond any doubt, that you don't know enough to be rewiring a house.

• For a circuit to supply a given load, how would you go about deciding what cable and protective device to use?
  
  
• Do you know which circuits can be ring finals and which cannot, and what the advantages and disadvantages of each are?
  
  
• Do you know what the two main lighting circuit topologies are, and what the advantages and disadvantages of each are?
  
  
• How do you calculate maximum demand and how can diversity be used?
  
  
• 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?
  
  
• Can you correctly identify all components and connections of a circuit by method of testing or otherwise? In doing so can you identify or recognise anything wrong or dangerous with the circuit?
  
  
• 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?
  
  
• What are the rules for cables run outdoors, buried in the ground or overhead?
  
  
• Where cables need to be joined, how should this be done / not be done and in what circumstances are different methods acceptable?
  
  
• Can you identify extraneous conductive parts, and do you know the requirements for main and supplementary bonding of them?
  
  
• Which circuits should be RCD protected?
  
  
• How do you propose to isolate your supply so that you can connect up your new CU?
  
  
• Do you know what tests you would carry out on the installation - what sequence you'd do them in and at what point you would energise the installation, and for each test do you know 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?
  
  
• What will you (convincingly) tell the council will be the way you'll ensure that your work will comply with Part P?

The thing is, rewiring a house, installing a new CU etc is not a trivial job, and I can assure you that it involves knowing far more than you think it does.

Asking questions here can be a useful part of a learning process, but they are not a substitute for proper structured studying. The key term there is "learning process" - you cannot learn all the things you need to know just by asking questions here. It isn't structured enough - it won't provide you with a way to progress where each step builds on what you learned before.

You can't carry out a job of this magnitude by asking whatever random questions happen to occur to you. You've already shown that you have some dodgy misconceptions - what if you get something wrong because you have no idea your knowledge is wrong? What if you miss something because you simply have no idea it even exists, and just don't realise you don't know it?

• //www.diynot.com/wiki/electrics
  
  
• //www.diynot.com/wiki/electrics:books
  
  
• http://web.archive.org/web/20080213151445/http://www.kevinboone.com/electricity.html
  
  
• http://web.archive.org/web/20080213151445/http://www.kevinboone.com/domesticinstallations.html
  
  
• http://www.tlc-direct.co.uk/Book/1.1.htm[/list]I suggest you get stuck into the last link right away - it won't give you design ideas, and unfortunately it doesn't refer to the current edition of the Wiring Regulations, but it's free, and will still give you a good grounding which you can augment with more up to date publications.
  
  As for what to have where etc, think hard about where to have sockets - it's difficult to have too many, and also about what circuits to have. The items on the list below won't all apply to you, but they are worth thinking about:
  
  • Upstairs sockets
  • Downstairs sockets (or a L/R or front/rear split)
  • Kitchen sockets
  • Circuit for appliances
  • Cooker circuit
  • Non-RCD circuit for F/F
  • Non-RCD circuit for CH boiler
  • Dedicated circuit for hifi
  • Dedicated circuit for IT equipment
  • Upstairs lights
  • Downstairs lights
  • Lighting circuits with switches in the usual places but with 2A/5A round pin sockets at low level.
  • Immersion heater
  • Loft lights
  • Shower
  • Bathroom circuit
  • Alarms
  • Supply for outside lights
  • Supply for garden electrics
  • Supply for shed/garage
  Plus any peculiarities brought about by your house layout & construction - e.g. in mine because of solid floors and where the socket circuits run, I have a radial just for a socket in the hall, the doorbell and the porch lights.
  
  Unless you want to go to the expense of RCBOs throughout, the CU should have at least 3 sections, 2 on RCDs and one not into which you can install a mix of RCBOs and MCBs.
  
  It can be a good idea to put all wiring in conduit for ease of future changes. And if you specify metal conduit for switch drops, or BS 8436 cable it removes the need to have RCDs on lighting circuits (apart from bathrooms).
  
  If you live somewhere where supplies are dodgy in the winter, have the lights, the boiler supply, and a socket in each room wired to a separate CU, or a separate section in a large one, that can be supplied by an emergency generator - lights, heating, TV and a kettle/microwave make life a lot more bearable.
  
  Flood-wiring with Cat6 or Cat6a cable is worth thinking about.
  
  
  When you look for an electrician (as you must, you really cannot do otherwise), personal recommendations are always the best way to find a reputable tradesman, but if you're having to go ahead without much in the way of those, or references, don't put any store by registration itself - sadly it is possible to become registered with woefully inadequate qualifications and zero practical experience. You don't have to spend long here to see people cropping up who are registered and "qualified", but who are clearly seriously incompetent in reality and who should not be charging for their services.
  
  You are looking for someone to rewire a house, and it may surprise and dismay you to learn that it is quite possible to become a "Competent Person" without ever having done that before, and without having acquired any of the practical skills needed to do it without half-destroying your house in the process.
  
  It's your money, £'000s of it, and you have every right to ask prospective tradesmen what their qualifications and experience are. Just being listed here is not a good enough guide. No genuinely experienced electrician, with the "full set" of C&G qualifications will mind you asking - in fact he will wish that everyone was like you.
  
  I feel sorry for people who have been misled by training organisations and (shamefully) the Competent Person scheme organisers into thinking that a 5-day training course, a couple of trivial examples of their work and some basic understanding of how to use test equipment will make them an electrician, but not sorry enough to agree with them trying to sell their services to Joe Public.

 

[PBSCO]

Thank you Ban-all-shed for your very detailed and informative reply....but maybe you should have read my post properly.....Nowhere did I put that I was planning to wire anything up....all I wanted to know was about 2.5 twin and earth and if the cable my friend gave me was suitable for a new ring main.Hence the leaving a loop of cable where the sockets are going to go.

I should have been a bit clearer about all the sockets as if they were all wired in properly they would have been fine...What I should have put was 25 sockets that had spurs off of spurs off of spurs.

I like to think I am an expert in my own field,so not a total moron...hence the turning power off tracing wires back and removing all non essential spurs for now.

Not sure how much use drawing a diagram of a circle would be to me at this point as that's all a ring main is.

Maybe I should have worded my post more carefully and I will do so in future and maybe not post after working for 3 months without much of a break.

I don't have to run any cable in right now but thought it a good idea to get some feed back on if separate rings for lounge,dinning room and hall...Kitchen, beds and bathroom,would be a good idea.

ceilings are quite high and leaves me a 6/7 inch gap at the bottom after 2400x1200plasterboard goes onto wall,so making skirting in two parts so this will create a small gap behind if I need to run any cables or pipes,either now or in the future.

Walls that are to have either up lights or down lights are being battened off,so I can fish wires behind walls when the boss decides where she wants them.

Not quite sure what questions I should be asking then...maybe ones I already know the answers to.

 

[calorific]

Electricians aren't as dear to hire as you'd think. Since a local lad will be able to design, install and write off your requirements it may well be worth your while talking to one. If you are very lucky, you might find one who will allow you to do the donkey work and thus reduce costs.

 

[ban-all-sheds]

Thank you Ban-all-shed for your very detailed and informative reply....but maybe you should have read my post properly.....Nowhere did I put that I was planning to wire anything up....all I wanted to know was about 2.5 twin and earth and if the cable my friend gave me was suitable for a new ring main.

In other words you wanted to know about designing circuits - choosing cable size is what that's about, and it requires you to know about voltage drop, to be able to predict R1+R2, to know how installation method affects current carrying capacity etc.

You were also asking about the same design issues for lighting circuits.

And the fact that you've decided on rings means you think you know about their characteristics and that you know that they are the most appropriate design for all of your socket circuits, even though the ones you list tend to have quite different requirements.

Hence my second question.

And it goes on..

Hence the leaving a loop of cable where the sockets are going to go.

So now you're into installation - if you want to put cables in you have to know what the requirements are for routing them, chase depths in walls, how their current carrying capacity might be affected...

I should have been a bit clearer about all the sockets as if they were all wired in properly they would have been fine...What I should have put was 25 sockets that had spurs off of spurs off of spurs.

You said it was a radial - thats how they are and there's nothing wrong with it.

But you didn't know that.

You said nothing about why you originally assumed it was a radial. Was it because of the rating of the protective device? You didn't say if that was wrong for a radial.

I like to think I am an expert in my own field,so not a total moron

Nobody suggested you were, but you do seem to be unaware of all that is involved in doing what you are proposing to do, even if you don't actually fit accessories.

Not sure how much use drawing a diagram of a circle would be to me at this point as that's all a ring main is.

No, it isn't, as in there is more to it than that because of concerns about unbalanced loading.

I don't have to run any cable in right now but thought it a good idea to get some feed back on if separate rings for lounge,dinning room and hall...Kitchen, beds and bathroom,would be a good idea.

You didn't ask whether rings per se are a good idea.

Do you see what I mean?

ceilings are quite high and leaves me a 6/7 inch gap at the bottom after 2400x1200plasterboard goes onto wall,so making skirting in two parts so this will create a small gap behind if I need to run any cables or pipes,either now or in the future.

You aren't allowed to run cables behind skirting boards.

But you didn't know that.

Do you see what I mean?

Walls that are to have either up lights or down lights are being battened off,so I can fish wires behind walls when the boss decides where she wants them.

No noggins? I wouldn't advise that.

Not quite sure what questions I should be asking then...maybe ones I already know the answers to.

That's my point - you can't acquire the knowledge you need by asking, because you will only ask about things you realise you don't know.

 

[OwainDIYer]

I should have been a bit clearer about all the sockets as if they were all wired in properly they would have been fine...What I should have put was 25 sockets that had spurs off of spurs off of spurs.

That's all right if it's a radial circuit, not all right if it's a ring.

 

[PBSCO]

Maybe I am asking the wrong questions.

What size cable would a professional electrician use in a normal 3 bed house if he were to wire a ring main for 2 rooms down stairs and 2 bedrooms with a small box room upstairs.(on separate rings)

As a ring feeds the cable from both ends would there be any voltage dropoff if he tested R1+R2? with max4 doubles in each room (both rooms added together are roughly35 m2.

Sorry had to lol at noggins between batten...never seen 2x1 batten at 400 centers with nogs before.(kinda defeats the object of battening the wall so I can drop cables from above for switches.

Not sure how leaving a loop of cable so it can be wired to a socket is installation either but...whatever.

Not all but some of the existing wires have been run behind the skirting and wrapped around gas and hot water pipes,so will run under floors and try to fish under new parquet floor in dining room( not finished right up to walls anyway,due to pipes and wires around skirting.)

the rest of your comments I just cant be bothered to answer because they are not relevant.

 

[flameport]

Planning to get all the cable in while I have access to walls and under floors(when the boss tells me where she wants sockets) and leave a loop for each socket to be wired up and a meter tail where new CU is going.

After this is done, who will be connecting this cable to the sockets and other items?

 

[PrenticeBoyofDerry]

Maybe I am asking the wrong questions.

What size cable would a professional electrician use in a normal 3 bed house if he were to wire a ring main for 2 rooms down stairs and 2 bedrooms with a small box room upstairs.(on separate rings)
[/quote]
Depends on the method of installation and any correction factors, but normally 2.5mm T&E would do.

As a ring feeds the cable from both ends would there be any voltage dropoff if he tested R1+R2? with max4 doubles in each room (both rooms added together are roughly35 m2.

There would be some voltage drop, but whether it would be beyond the permitted value would depend on the length of the circuits cable

Not all but some of the existing wires have been run behind the skirting and wrapped around gas and hot water pipes,so will run under floors and try to fish under new parquet floor in dining room( not finished right up to walls anyway,due to pipes and wires around skirting.)

Not uncommon to find cables run behind skirting and wrapped around the plumbing, needless to say, not the best of methods.

 

[PrenticeBoyofDerry]

whats the rationale behind rfc on up and down?

There is none, just the way I would do it, providing the circuit could be designed and routed logically. I would be happy to run radials, if not.

 

[ban-all-sheds]

Maybe I am asking the wrong questions.

Do you say that because you aren't getting the answers you think you should?

What size cable would a professional electrician use in a normal 3 bed house if he were to wire a ring main for 2 rooms down stairs and 2 bedrooms with a small box room upstairs.(on separate rings)

That would depend on the installation method. It's possible that 6mm² might be needed.

But then a professional electrician will know and understand that - you, OTOH, don't have a clue.

As a ring feeds the cable from both ends would there be any voltage dropoff if he tested R1+R2? with max4 doubles in each room (both rooms added together are roughly35 m2.

You think you can rewire a house - you tell us. How will you measure your R1+R2? Or r1+r2.

Sorry had to lol at noggins between batten...never seen 2x1 batten at 400 centers with nogs before.(kinda defeats the object of battening the wall so I can drop cables from above for switches.

You obviously have greater faith than I in the strength of plasterboard.

And also a shameful attitude to doing a good job - something which does not fit well with doing electrical work.

Not sure how leaving a loop of cable so it can be wired to a socket is installation either but...whatever.

Did you plan to just leave a loop of cable lying on the floor, or did you intend to actually put it somewhere, like in a wall, or under a floor?

THAT'S INSTALLING IT, YOU T**T.

Not all but some of the existing wires have been run behind the skirting

Doesn't matter - it's not allowed, and you may not replicate it.

so will run under floors and try to fish under new parquet floor in dining room( not finished right up to walls anyway,due to pipes and wires around skirting.)

You've had new parquet flooring put down down before rewiring?

You need to sack the guy you have project managing this refurbishment - he's an incompetent buffoon.

the rest of your comments I just cant be bothered to answer because they are not relevant.

No doubt you wish they weren't.

But you're an ignorant fool who doesn't see why ignorance should be a reason not to plough on, so what do you know?