No earth wire in lighting circuit?

[CRAIGNEWHAM]

Hello,

I am going to change my consumer unit in my flat before putting it up for sale, (I will be doing the work myself, but be informing building control to comply with building regulations) and have found I have no earth wire for the lighting circuits, just 2 black wires. Is it acceptable to leave these in if the lights and switches are class II or plastic, or will I need to change them anyway so that any tests done on the new consumer unit will conform to 17th edition?

Cheers
Craig

 

[ericmark]

Go Here and read guide 1.

Not saying I agree with what it says but good start.

 

[holmslaw]

..

 

[riveralt]

Hello,

I am going to change my consumer unit in my flat before putting it up for sale, (I will be doing the work myself, but be informing building control to comply with building regulations) and have found I have no earth wire for the lighting circuits, just 2 black wires. Is it acceptable to leave these in if the lights and switches are class II or plastic, or will I need to change them anyway so that any tests done on the new consumer unit will conform to 17th edition?

Cheers
Craig

Hi Craig by informing building control do you mean that you will be completing the EIC?
Because you will have to put on that document the readings from your test results.
This, of course, will highlight that you have no cpc to the lighting circuit - which in itself is not an issue provided there are no metal switches or light units.
However it will probably be raised by the potential buyers to reduce the price of the house. Unless there is conduit in place then there is a fair amount of work to do to fit a new cpc or new T&E to the lighting circuits.
It might be best to leave it as it is.

 

[sparkwright]

Not sure why your lighting consists of two black wires.

Is it in conduit?

Pyro can consist of two wires with black sleeves.

The only place where I would expect to see two black wires would be an end-of-circuit ceiling rose, where possibly the reds (and earth) are shoved into the ceiling void.

Why are you going to the trouble of replacing the cu?

 

[CRAIGNEWHAM]

Sparkwright
I'm changing the cu as it has 2 really old small ones at the moment, and so I'm pretty sure a surveyor will advise any potential buyers to get the electrics checked, and they may therefore try and knock the cost of a re-wire off the asking price. So I'm trying to be pro-active.

Yes, it looks like all the wiring is in conduit.

Riveralt -
I would do the EIC, I have the equipment. So would it technically comply with building regs so long as all the fittings were plastic? what about any metal back boxes?
Am I ok to do this so long as I dont make any of the installation 'any worse'?
It seems most of my sockets dont have earth wires either?

Thanks

 

[holmslaw]

..

 

[flameport]

I'm pretty sure a surveyor will advise any potential buyers to get the electrics checked, and they may therefore try and knock the cost of a re-wire off the asking price.

Replacing the CU will not change this - it could actually make it worse.

Current situation - old fuseboxes, survey will say 'electrics should be checked' - most people will not bother to go further because most home buying surveys will say that.

New CU situation - buyers will want copy of EIC due to recent work done, this will list defects such as no CPC and who knows what else, they will then want a rewire, knock down the price and on top of that you have paid out for the new CU as well.
There is also the possibility that if the CU change is not done 100% properly this will alert potential buyers to dodgy DIY and put them off buying the place altogether.

 

[sparkwright]

Sparkwright
I'm changing the cu as it has 2 really old small ones at the moment, and so I'm pretty sure a surveyor will advise any potential buyers to get the electrics checked, and they may therefore try and knock the cost of a re-wire off the asking price. So I'm trying to be pro-active.

Yes, it looks like all the wiring is in conduit.

Riveralt -
I would do the EIC, I have the equipment. So would it technically comply with building regs so long as all the fittings were plastic? what about any metal back boxes?
Am I ok to do this so long as I dont make any of the installation 'any worse'?
It seems most of my sockets dont have earth wires either?

Thanks

You say it looks like conduit. Do you mean just conduit at the switch drops, or the entire lighting circuit? Are the cables 'singles', or actual cable? Is the cable PVC?

If it is conduit, is it metal or plastic? A full metal conduit system should imply that the conduit is itself earthed. Though the really old narrow 'grip' conduit cannot usually be relied on to give a good earth.

Are you certain it's not pyro (mineral insulated cable)?

Pictures would be very useful.

 

[electronicsuk]

I don't think you'll achieve much by changing the CU. If a rewire is well overdue then a decent surveyor will soon spot this by removing a socket or light switch here and there, and your buyers will still want a reduction in price. You will then end up even more out of pocket, as you've wasted money on a new CU and LABC notification fees.

 

[dingbat]

If a rewire is well overdue then a decent surveyor will soon spot this by removing a socket or light switch here and there...

Best laugh I've had in a long time!

The very idea of a surveyor actually carrying out a detailed inspection.

No, unlike sparks, who foolishly and naively spend all day inspecting and testing before issuing an unsatisfactory PIR (for which the unhappy client is not prepared to pay) a surveyor takes your money up front (loads of it) then cobbles the 'survey' together on his laptop in McDonalds, prior to taking a cursory glance to count the number of rooms. (They don't always get that last bit right, either!)



Seriously though? A non-electrical surveyor will absolutely not remove any covers for inspection and the recommendation to have all services checked out is standard boilerplate accompanying every 'survey' I've ever seen.

 

[CRAIGNEWHAM]

Thanks Sparkwright -

I'll check if its metal tomorrow but I'm pretty sure it is, and get some pictures.
I can see conduit going upwards from the light switches, and when I changed a light fitting (class II) before in the living room, I'm pretty sure it had some sort of conduit running over the plaster board in the loft (and a junction box above the light). Black stuff that I think was metal too. Will this be connected to the earth terminal at the cu?

The sockets look the same too in the living room.

 

[sparkwright]

It is usual for flats to be wired in 3/4 " or more recently 20 mm circular conduit. If this is metal it is regularly connected to a metal fuse board. The board should be earthed, and the board will then earth the conduit. This will earth any metal back boxes. To earth any metal fittings, an earth wire can be taken from the conduit box to the fitting.

Pyro or MI systems achieve earth continuity in the same way.

If you have either of the above wiring methods, your new consumer unit should be metalclad.

Pictures will be invaluable here.

If the conduit is much narrower than 3/4 ", more 1/2 ", and has old, crumbly, non-PVC wires then it will need replacing. This is known as grip conduit. Hopefully you don't have this.

 

[ban-all-sheds]

I will be doing the work myself, but be informing building control to comply with building regulations.

There's more to complying with the Building Regulations than just notifying - complying with P1, for example, so when you apply for Building Regulations approval what do you plan to say will be the way you'll comply with that?

Is it acceptable to leave these in if the lights and switches are class II or plastic, or will I need to change them anyway so that any tests done on the new consumer unit will conform to 17th edition?

It doesn't bode well that you have to ask that, because there are all sorts of other things that need to be right to comply with the Wiring Regulations.

• For a circuit to supply a given load, how would you go about deciding what cable and protective device to use? (No, you can't just copy what's there because it's going to become your responsibility and what's there might be wrong.)
  
  
• Do you know which circuits can be ring finals and which cannot, and what the advantages and disadvantages of each are? (No, you can't just copy what's there because it's going to become your responsibility and what's there might be wrong.)
  
  
• How do you calculate maximum demand and how can diversity be used?
  
  
• 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? You cannot assume that what's currently installed is OK, and you need to check it before starting work.
  
  
• Do you understand how the way in which cables are installed affects how much current they can carry? (No, you can't just copy what's there because it's going to become your responsibility and what's there might be wrong.)
  
  
• 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?
  
  
• Are you going to do any testing yourself, or is your plan to bung it in and hope that when your LABC, or the person they or you appoint, come to test it that everything will be OK?
  
  What if it's not - how much will it cost you to fix it and then pay for a second visit?
  
  If you are going to check your own work 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?

Installing a new CUs 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. 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?

 

[CRAIGNEWHAM]

Thanks Sparkwright -

I've attached some photos, are these anygood?
The first one is of a socket in the living room, the other 3 are of light sockets?

Does it look like pyro/MICC??
Would it be ok to leave this as is as long as it conforms with r1+r2 / insulation resistance tests etc?

Cheers
Craig