High Ze

[dingodeano]

Hello Gang.
Had a high Ze reading yesterday on a TNS supply i was doing a PIR on pre consumer unit change (or should that be EICR ?) . Anyway the Ze was 33 ohms .
Told the customer to ring his supplier and see if they coud come out and sweat a new earth on sheath or maybe convert to PME and while he was on get an isolator fitted.
He rang me today the supplier (a lady) told him that any work AFTER the meter was his responsibilty ......
So i was wondering is their anyway of making them do something ? do they have a duty of care to provide a suitable earth ? or do we just accept that he has to fork out for me to put some rods in.

 

[Wontdothatagain]

If you are sure the terminals at the main switch are tight, then phone the DNO and tell them not the supplier. It should be treated as an emergency.

You have no way of working back from the main switch and as it appears there is a fault, it is their responsibility to repair it.

 

[dingodeano]

So they are obligated to maintain the earth they have supplied?.

 

[RF Lighting]

Yes that's correct.

Phone the DNO. Tell them you're a contractor and report a high Ze

My DNO normally attend within 2 hours

 

[Wontdothatagain]

What he said

 

[dingodeano]

muchas gracias. i owe you both a virtual pint.

 

[sparkybird]

It will depend on the DNO - down here in EDF land they will deny any responsibility for provision of an earth and its up to the customer to pay for one of the following

a) if possible, EDF to sweat on an earth @ £400
b) PME via new supply -£2-3K
c) sparks to install earth rod..... they mostly go for this.....

SB

 

[dingodeano]

oh. Well im in the Mids. i will give western power a ring tomorrow and make sure i use words like 'duty of care' and 'unfit for purpose'.
I find it hard to believe that they supplied a TNS but now for whatever reason the earth is defunct that they would leave it upto the consumer to get it sorted at his expense and continue to charge for their service. sounds like a win win for the supplier they just keep collecting the quarterly charge regardless.

 

[RF Lighting]

I've reported a few to my DNO (YEB, YE, YEDL, CE Electric, Northern Powergrid, or what ever they are calling them selves this week)

They have always been really good, and sent someone out straight away.

The last one I had I rang through at 5pm. There was someone on site by 6.30pm.

He did a quick Ze, and his result matched mine. The following morning two chaps turned up, replaced the cutout, and provided a new earth. Never any questions asked, no grief given, and all free of charge.

 

[securespark]

Round here, Norweb (ENWL) usually fit a clamp, if it's TN-S.

This week I had a high Ze on PME, that's when it decided to play ball...

I first got a N-E reading of 41V..... Then a Ze of 183 Ohms....

 

[westie101]

If there is an EXISTING earth provided by the DNO (not the supplier) they have a duty under ESQCR to maintain it, no ifs no buts.

If there is not and never has been an earth there is NO DUTY to provide one.

However if it is a property built since 2002 there was/is a duty to provide an earth.

Please, please don't start requesting TNC-S if it is not already, as this is possibly an upgrade so may be refused, just ask that it is maintained.
The decision of the type of earthing provided is the DNOs

Oh and finally it is far, far better that you the electrician ring us rather than the customer. at least we get the story first hand and can, often, understand what is needed.

 

[17thman]

there are advantages and disadvantages from swapping from a tns to a pme. You may gain a better disconnection times and thus longer circuit lengths may be possible. My dno will change a broken/inadequate tns for pme for £150.00. But it has changed to western power recently.

But what if you are supplying and outbuilding with extraneous conductive parts. That cannot be ignored, when changing the supply type.

 

[RF Lighting]

It doesn't make any difference. The same rules apply to out buildings with E-C-Ps whether the supply is TN-S or TN-C-S

You either extend the equipotential zone or TT the external supply.

 

[sparkybird]

the problem with EDF is getting them to agree that the existing earth was originally supplied by them - they refuse to accept clamps or bands (which 99.9% of earth's I see ) and will only maintain a sweated on/braided earth connection.

It's just easier to rod it in the end

 

[17thman]

It doesn't make any difference. The same rules apply to out buildings with E-C-Ps whether the supply is TN-S or TN-C-S

You either extend the equipotential zone or TT the external supply.

So if you exported the earth from a tns to an outbuilding that had e-c-p and then the supply was converted to a pme, the outbuilding would then need to be tt'd and the cpc cable be disconnected from the earthing terminal in the outbuilding.