Earth Bonding - No Earth Terminal on Incoming Mains Supply


I have just discovered that my house has no earth connection provided by the electricity supply company. It has in effect an old sub mains pair of red and black cotton/resin covered tails coming straight through the wall in the cupboard under my stairs from next door in metal conduit. The main supply head must be is located next door (the house next door is empty and I am trying to trace the owner at present to gain access) which presumably has a properly bonded earth connection point. The old red/black incoming supply tails have a fairly modern grey main company fuse head on them but the normal earth outlet (next to the neutral connection) has not been connected and remains in its factory sealed/unopened state.
The electricity supply company has not provided me with an earth connection. An electrician suggested I got access next door and ran a large earth wire from their main earth connection through to mine. I will check what has been done inside my consumer unit as I suspect the earth and neutral bus bars may have been linked to provide protection.
What should I do as I intend to replace the old Wylex consumer units with a modern 17th Edition RCD/MCB split box. I have no official earth point so wonder what can of worms I may end up with. Is it OK to link Earth/Neutral in my own consumer unit?
If the owner lets me in next door I can get their earth connection brought through which is probably best. I understand that installing my own local earth rod is not the best way forward.
Thanks
Graham
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Hi Graham
A photo of your cut out and one of next doors would help (when you get access). It is an odd set up but not unknown.
The most sensible thing would be to ask your supplier to supply you with an earth.
I would suggest that you do not connect the neutral to the earth inside your CU for two reasons.
1. You do not know if your supply is PME and if it is not then it could be dangerous to try to make it a PME supply.
2. If you connect the neutral and earth bus bars together in a RCD CU the RCD will almost certainly trip as soon as you turn the power on.
HTH
Adam
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Thanks for your advice Adam.
I will send you a photo when I have access to next door.
I certainly do not intend to do a DIY PME conversion. I am not sure what has been done inside the old Wylex fuse box yet until we get back in there on Monday. If a Neutral/Earth link has been been done by the previous owner over 20 years ago then it is likely to be fairly safe as it is in a town and is already likely to be PME in the street.
I am aware of how RCDs work and understand your comment about them tripping if N/E is connected together. I will have to get the Electricity supplier in at some stage but am reluctant to do so until we have improved the wring as far as we can take it as they may well just disconnect everything leaving us with no power to do remedial work. My electrician is able to install a new consumer unit over the next few days and then I can call in the supplier to provide the proper earth connection when we finally get into next door. I am going to have to trace the owner or wait for them to respond to my letter posted in their empty house.
I am wondering whether it will work if we upgrade to a proper dual RCD protected CU now and put all the earth wiring in with a new main earth connecting block ready for a proper earth connection later. I would certainly not connect N/E together in a new RCD CU. Surely an ordinary RCD (NOT the new type RCBO which must have its own earth connection) should not trip if the earth is not actually present (assuming no other faults on the internal house wring). It should be much safer than the present arrangement while we are waiting for our proper earth connection.
What do you think?
Graham
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It is noted that you are not going to do a diy PME :-)
The RCD would offer some protection if you were to touch a live cable. Also if your main bonding is up to standard and the water supply is metal then there is good chance that there is already an effective earth (although the water supply should not be used as the main earth it will work).
An RCD will not trip because there is no earth. It is more likely not to trip! An RCD will still makes things safer. I like the idea of getting a CU ready with an earth block waiting for the new earth.
Past experience suggests that the Wylex board will not have the earth and neutral bars connected together. There may be an earth rod that you do not know about but it is more likely that there is no earth at all.
A house I worked on last week had no main earth and no bonding. I took an earth loop reading at the supply before I started work and found that it was 220 ohms. This earth was probably created by electrical connections to the boiler etc and used the copper pipework in the house to get this earth. An RCD would have worked with that sort of reading.
Cheers and good luck getting into next doors
Adam
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some earth bonding to the water and gas pipes onto the new earth block/CU internal block. The presence of RCDs will give partial protection until the new earth connection is brought through from next door.
A few years ago I installed an isolating transformer on my boat and disconnected the earth from the marina shoreline supply to stop galvanic corrosion of the hull. This is standard marine practice as it stops you getting a shock between baot and shore in the event of a fault. I bonded one side of the secondary straight to the hull to create a "local isolated onboard earth" so there was a reference point from which an RCD on my boat could trip in the event of an on board fault. So I fully understand that in this domestic case an RCD will not give a false trip because of a lack of earth but may be less likely to work to spec until the earth is properly connected later. I will use a combination of Land Registry and an internet missing person trace to locate the owner if they fail to respond to my letter at the hose. I am told the owner may be elderly so may not want to cooperate but the electricity supplier could enforce access through the courts if it comes to it but hopefully that will not be necessary.
Thanks
Graham
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I had to check that you knew how an RCD worked:-) I need not have asked.
I will use a combination of Land Registry and an internet

So the owner is possibly in a home or with a relative then?
Either way, s/he will have a younger relative who will cooperate with you and save the hassle of forced entry (hopefully). Do you know if anyone is collecting the mail from the empty house? The post might be redirected via the post office to a different address. It could be worth a stamp to try it out. BTDTGTTS with a house that was empty for 12 years. The owner was in a home and all mail was redirected to her sons house.
Adam
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I have only now picked up on this thread, but if it helps I managed to conatct the owners of an empty house via the council. They would not give me his address but were happy to address and post on a pre stamped letter on my behalf.
Mike
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Earth rods are no big deal. I have got to install one outside a cottage in a small village next week. Correctly installed they are just as safe as PME and TNS systems.

I think that you will have to wait for a reply from the mortgage company. It is still early days and without seeing what is on the other side of the wall then your only two options are TT or pay for a new supply.
Could you post a picture of your side of the supply?
http://tinypic.com/
seems to work well. Just post your link to your photo.
Adam
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I would tell EDF to shove off and TT the supply.
This sounds like a Loop-In supply. - Loop-in supply are illegal to install under ESQW - Whether they be jn-box (cutout) or jn-box under your driveway - However EDF are liable for maintaining the existing service
Thus EDF would be most grateful if you would remove their future liability (when the supply cable blows) by paying for it yourself :-) Tell them where to go. The distribution industry is trying to pass every buck-cost onto the consumer.
Nothing wrong with TT. There is a VERY remote possibility that the UK might go TT eventually. It is expensive to maintain PME, it is expensive to maintain Ze sufficiently low for 100A BS1361 fuses hence the practice of fitting 80A & replacing 100A with 80A.
Loop-In supplies can bite people, particularly if PME. - Downstream neighbour loses Neutral - 10mm MEB to lead CW & iron Gas takes house current - No-one the wiser UNTIL they cut either pipe
Running a PME earth "next door" is certainly out as it introduces fault currents into their house re fire risk AND leaves your earth vulnerable to whatever anyone may do next door (such as attach it to a screw into the wall :-). So TT as it stands is a perfectly acceptable option. TT means you get a house disconnect on 100mA fault (time delayed re Type-S) so you actually gain a slight fire benefit downstream of that RCD (not that it means much in modern "30mA RCD everything 17th regs").
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Hi Adam
I uploaded a photo showing a metal conduit and the L/N tails coming through from next door into my house.
I got a phone call from the owner of the house next door. It appears she is a landlady and she was fobbing off my tenant as they probably do not get on. I did write a rather stern letter threatening legal action of we had to get a court order for access. I Am going to look at it tomorrow and take a photo for my electrician.
I will do everything possible to bring the earth through as it must be feasible, She has had her side tested for a Housing Association let in the past but it may no be very obvious that a second sub-mains was taken off it if it was hidden under the meter board. Hopefully all will become plain tomorrow.
I am reluctant to install a TT earth rod but I guess that would be cheaper than a new supply. It may be best in the long run the have a new supply but there are plenty of houses out there with this rather old style installation and I would be happy with an earth clamp from next door with a new RCD CU.
Thanks for your interest
Graham
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Where?
You cannot attach the photo to your newsgoup post. You need to upload to http://tinypic.com/or similar and post the unique link that you have created on their site.
Adam
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Sorry Adam I never used this service before. I uploaded photo to
http://tinypic.com/r/ixs6le/3
This should work OK.
I just heard from the owner next door and she promised to let me in today to look at the mains service connection her side. She then changed her mind (she said she had talked to her electrician and EDF who said it was not necessary to let me connect my earth to her side) and refused to cooperate.
I am not sure why she is objecting but I think it best to try and be independent from next door as I cannot trust her or any future owner from tampering with my earth connection. They are less likely to interfere with the live mains connection as it looks more serious.
My electrician will attempt to install an earth rod, which he and I do not like, but if we can get a good earth loop impedance result then my new RCD board should work safely. I can then decide later whether to go for a new PME supply.
I do not think I have many other options at present as I cannot rely on the current iron gas pipe earth which, apart from being not allowed, may end up in plastic in the future. She will have to let EDF in to disconnect my side anyway.
What do you think?
Graham
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