Earthing Responsibility, Me or DNO?

[EDF Earthing]

Hi, I have recently had an earth loop impedance problem identified and the DNO has offered no help. My electrical knowledge is at best rudimentary so any advice would be gratefully received.

In 2006 the house was divided into 2 flats, our contractor did everything up to the fuse box, EDF upgraded supply and took care of everything outside of the fuse box.

We were left with TNS incoming supply, an earth clamp on the sheath and earth from here to the fuse board.

A couple of days ago we had an oven and hob installed, following installation the electrician tested the Earth Loop Impedance and found it to be 2.77Ω, he went to test the ELI at the supply and found it to be 2.65Ω, at one of the sockets it was 5.6Ω. Our electrician advised that this results from 'insufficient earth path' and is a potential danger.

He advised that we contact EDF to arrange PME as he did not think TT could solve the problem.

After hours on the phone and a dozen different stories EDF have advised that we are responsible for earthing the supply and that PME will require a new service cable at an anticipated cost of

 

[Marc]

As far as I know....

Suppliers are under no obligation to provide a means of earthing. However, if they do supply it, it is their obligation to maintain it.

Marc.

 

[revjames]

Did you get the Ze checked at the incoming supply with earth to CU disconnected? this will give the most accurate reading of the external earth loop impedance which I'm pretty sure is DNO responsibility to ensure its within acceptable limits ie TNCS 0.35 ohms and TNS 0.8 ohms. It has to be checked with earth cable removed so whole installation turned off at CU.

You say your experience is rudimentary. This test needs to be done by a qualified spark IMO

HTH

James

 

[Marc]

You say your experience is rudimentary. This test needs to be done by a qualified spark IMO

James

It was.

I presume your consumer unit is fully RCD protected? Or is it split-load?

 

[ian3012]

rev.... he said his sparks did it...

when you phoned edf john, you were probably talking to the tea girl, standing in for the receptionist.

if they supply a means of earthing... it's their responsibility to maintain it.

get back on the phone....

he was a proper sparks wasn't he?

cos you'll look a right banana if your earth isn't the problem....

 

[EDF Earthing]

Thanks James,

To my knowledge our Sparky did as you said, he certainly turned us off at the fuse board and disconnected a green and yellow cable in the cabinet where the service cable meets the metres before testing.

John.

 

[EDF Earthing]

I presume your consumer unit is fully RCD protected? Or is it split-load?

Hi Marc,

There is 63a RCD in the fuse box, it also says that MK Sentry CU must not exceed rated current of 63a, I hope that means that it is fully RCD protected - but this is conjecture on my part.

 

[Marc]

I presume your consumer unit is fully RCD protected? Or is it split-load?Hi Marc,

There is 63a RCD in the fuse box, it also says that MK Sentry CU must not exceed rated current of 63a, I hope that means that it is fully RCD protected - but this is conjecture on my part.

Does the RCD cover all breakers or just some?

Have you got any pictures of it? We like pictures.

 

[EDF Earthing]

when you phoned edf john, you were probably talking to the tea girl, standing in for the receptionist.

if they supply a means of earthing... it's their responsibility to maintain it.

get back on the phone....

he was a proper sparks wasn't he?

Thanks Ian,

After too many conversations to list with various parts of EDF I got onto Consumer Focus and they investigated and found a customer relations manager for me to speak to. Customer Relations Manager is confirming the situation before we speak again on Monday but thus far she has advised as I posted above.

Sparks is properly registered, we rent one of the flats through Kingston University and they stipulate that we use him.

John.

 

[Andy™]

if earthing is provided, it should be maintained.

however, your sparky is wrong and your going about this the wrong way

if you phone up and ask for it to be chanegd to TNCS, then you want it upgraded, and so you will have to pay for this to be done.

what you should be doing is calling them and telling them there is a fault with the earth connection to your building, and they will repair the TNS connection, or they may offer TNCS if they cant fix the TNS fault. sometimes they are useless when you phone them, so making it sound worse than it is, i.e the earth has failed and has a voltage on it etc, may be helpful

 

[vandalay]

I know another poster has mentioned it but if EDF have supplied a earth you say is TNS then need to maintain it and surely this is something they need to investigate, do neighbouring houses have had similar problems?

 

[EDF Earthing]

Have you got any pictures of it? We like pictures.

Here is a pic Marc, Looks like it might be only part RCD protected

View attachment 567

 

[Andy™]

thats a split load, with 3 left MCB's non-RCD protected

 

[EDF Earthing]

So could a part of the answer be to get fully RCD protected CU?

Apologies for my ignorance and many thanks for all of your kind responses.

John.

 

[Andy™]

So could a part of the answer be to get fully RCD protected CU?Apologies for my ignorance and many thanks for all of your kind responses.

John.

solution is to get DNO to fix fauult, and carry on as normal

CU will only need chaged to fully RCD'd if you do change it to TT

 

[Marc]

So could a part of the answer be to get fully RCD protected CU?Apologies for my ignorance and many thanks for all of your kind responses.

John.

Doesn't solve the problem of a high EFLI, but certainly improves safety. As Andy said though, the DNO needs to fix it. How many other flats are fed from that supply?

You said the EFLI was 5.6 at one socket....what was it like at the rest of the sockets on the circuit?

 

[sparkytim]

Hi

You may be talking to the wrong part of EDF

You need to call the EMERGENCY number and report you have a HIGH EARTH LOOP IMPEDANCE

They are responsible for this and should attend within 4 hours

The maximum it should be for TNS is 0.8 ohms at the supply point.

 

[batty]

Is shower on none RCD side looks like a 40 amp circuit breaker with shower on, that certainly needs to be RCD protected anyway makes you wonder why its been certificated with no Rcd protection on shower.

 

[Andy™]

was not a requirement to 16th, only to manufacturers instructions

 

[EDF Earthing]

Doesn't solve the problem of a high EFLI, but certainly improves safety. As Andy said though, the DNO needs to fix it. How many other flats are fed from that supply?You said the EFLI was 5.6 at one socket....what was it like at the rest of the sockets on the circuit?

Thanks Marc.

Just one other flat fed from supply.

Sparks checked earth loop impedance after installing oven and hob as a matter of course that was 2.77. He then isolated supply and found that to be 2.65, he took this as demonstrating that the problem was at point of supply not at point cooker was installed. He just tested one socket where the kettle is plugged in so that I had full info.

Cheers,

John.