Water/Gas used as sole means of Earthing

[m4tty]

Hi,

I know that using water/gas as sole means of earthing is not allowed anymore. I am looking at changing my dads old BS3036 board now instead of mine for assessment. Ive had a look at his board and there are two cables (green) going from earthing terminal (which is a screwlock looking thing) down to water and gas. (Done in 60's/70's)

If I was going to change this board I would have to convert to TT installingan earth rod.

Question: Is it ok to put the Earth rod under the floorboards and into the soil as this is not really accessible without removing capet and floorboards as the board/meter is under the stairs which is along way from outside.

I have only dealt with TNS and TNCS being in quite a built up area so TT phases me a bit as ive never come across one before.

Anyone give me any pointers as i would appreciate it alot.

Thanks

Matty:coffee

 

[Zeespark]

Can you not phone up your DNO and ask for TNS connection at all Matty?

AndyGuinness

 

[Evans Electric]

As Zee Zee says , try to get a TNCS or a TNS from the DNO otherwise its TT .

Can't see anything wrong with putting the rod under the floor but have a label made ,saying where it is . Would be best out in the garden though, might be too dry under the floor.

 

[m4tty]

Hi,

Thanks for the replies

As im new to all this who would be the DNO for SE London... EDF? and would it cost to have it TNS'd or PME'd?

Would I just have to ring them up and say that its Earthed through the services or is there some excuse I could give them to get it done for free? ray

Cheers

 

[batty]

Sure you have not got a TNS earth very unusual not to have one in London, a piccy of incoming cable would help.

 

[m4tty]

Yeah sorry ill get a picture over next few days.

 

[batty]

We like piccys.

 

[sparkytim]

Sounds like those 2 green wires could be old 6 mm Bonds.

Is there a BARE earth wire coming from "screwlock thing", thats an old style MET Nut and Bolt thru meter board, it would disappear into sheath of cable.

It there is then this is TNS NO STAKE REQUIRED.

Just replace the "screw lock thing" with a 4 way earth block, take a 16mm Earth from this to your new CU and upgrade the bonds to 10mm, (it may be 16mm in some parts of London) The bare Earth wire belongs to DNO so just connect it into the earth block with the 3 other new conductors. Dont attempt to disturb the other end it is swetted onto lead sheath.

(If there Is one of course, if not then revert to plan A) LOL

 

[fletchflash]

dno charge

 

[batty]

dno charge

 

[m4tty]

Sounds like those 2 green wires could be old 6 mm Bonds.Is there a BARE earth wire coming from "screwlock thing", thats an old style MET Nut and Bolt thru meter board, it would disappear into sheath of cable.

It there is then this is TNS NO STAKE REQUIRED.

Just replace the "screw lock thing" with a 4 way earth block, take a 16mm Earth from this to your new CU and upgrade the bonds to 10mm, (it may be 16mm in some parts of London) The bare Earth wire belongs to DNO so just connect it into the earth block with the 3 other new conductors. Dont attempt to disturb the other end it is swetted onto lead sheath.

(If there Is one of course, if not then revert to plan A) LOL

Thanks for replying everyone.

There is no bare earth wire coming from the met. Just 3 (6mm green bonds). First is the main earthing conductor which goes to rewirable fuseboard, 2nd and third run down under the floorboards which my dad says go to gas and water pipes. He installed it as his mate worked for LEB who gave him all the stuff to do it with in early 70's roughly.

I dont think this is a TNS as there is no bare earth wire (like mine indoors sweated onto sheath 4 bare wires twisted together) and looks like its using the service pipes as earth.

A while back when I got my new meter I dont some Zs tests on the downstair ring and the results were within BS7671. So its getting a good earth from them pipes.

Ill pop round there tomorrow and get the boards up and investigate where them cables go to and report back.

Thanks again for taking the time

Matt

Thanks again

 

[sellers]

If your getting good results mate it should be earthed.

You say you've got 3 x 6mm cables. 1 to each bond, then the other where does that go? does it go onto the incoming sheath (TNS), or to a connector on the side of the cut out which is linked inside to the neutral (TNC-S)

 

[sparkytim]

I think he said third wire was to CU

Sounds like half a job done in the past, maybe good Ze from incoming water main, with borrowed PME (TNCS) from next door

 

[m4tty]

Update: i've been around there and have found a bare earth cable which is stranded which goes from the lead water pipe to next doors and them bonds which go to met go to that same water pipe so it's definitely being earthed from the water pipe. Done a ze with bonds connected (zdb?) which came out at 0.19 with PFC 1.2ka. Whilst round there I had a look at next doors to see if I could find that bare earth wire but no joy. I did however find that they have tns with a bs951 clamp round incommer. My dads incommer is fed from next doors as his incommer does not come from under the floor but through the wall from next door. I've taken some pictures but don't know how to upload them from phone so when indoors later I will post them on here so you can get a better picture of the setup.

Cheers

 

[m4tty]

Heres the pictures taken

114- Lead water mains running through middle of photo. Can you see the thin stranded wire clamped onto this water pipe.

115- 3 Earth Bonds going to 'screwlock' met. 1st goes to BS3036 and 2nd & 3rd disappear through cladding but can trace on of them going to clamp on lead water pipe. Cant trace the other.

116- Old Wooden framed BS3036

117- Closer up view of lead water pipe with clamps on. The clamp at the top of the photo connects bond back to met.

118- Bonds disappearing through cladding (pointless photo sorry)

120- The cable at the top left of the photo is solid which I think may go through to next doors TNS sheath. But when I looked next door I couldnt see it there. However Ze 0.19 so its getting good earth from somewhere.

121- Junction boxes found under the floor.

You lot must have come across this sort of thing a lot? it looks like a mess to me and am at a bit of a loss where to go from here. Do you recon I should contact the DNO and ask for a TNS connection. Please dont say contact an Electrician as im trying my hardest to fathom this lot out, and am sure you lot have seen loads like this.

Thanks for any help and comments.

Cheers

Matty

 

[ianmacd]

Contact DNO and ask them what Earthing method you have here? Shouldn't water company be replacing those old lead pipes too?

 

[m4tty]

Will contact DNO now, do you know who the DNO will be .... EDF. Its in Kent/SE London. Not sure about lead water pipes.

Cheers

If it is EDF does anyone know their number?

Thanks

 

[m4tty]

http://www.nationalgrid.com/uk/Electricity/AboutElectricity/DistributionCompanies/

found this. Is that the number ive gort to call.

Thanks

 

[m4tty]

Just rung edf and they said that its not their responsibility and i need to contact the energy supplier who will send a meter man out who will loop test it and sort the earth out. Not sure if ive been fobbed off. What do you guys recon. I know about ESQCR regs saying that if they supply a earth they have to maintain it.

Ive spoken to them again and theyve said as its a looped supply from next door if my dad rung and asked for it to be unlooped and a new supply put in they would charge for it but if next door rung up and asked for it to be unlooped then it wouldnt incur a charge.

They also said that they do not install TNS anymore and would have to be PME via supplier.

Think next step is to call Southern Electric and ask for them to come round and do a loop test and sort earth out.

My dad had a new cutout installed a few years ago but they didnt bother touching the Earth and they didnt seal the cutout either. Do you recon it may be a good idea to have a look inside the cutout to see whether the PME connection is ready to be connected. I know I cant do this connection as its suppliers property and we can only touch stuff this side of the meter.

Thanks for any advice.

Matty

 

[ianmacd]

So they had no record of the Earthing type they installed?