High Ze

[securespark]

Went to customer today with high EFLI.

Traced it to a high Ze.

We cannot turn off power without permission, so left paperwork explaining problem & rang DNO (UU) to arrange visit by them to rectify high Ze.

Returned to property later to check progress. UU guy turned up as I arrived.

He got a Ze of 1.5 & proclaimed it OK for TN-S!

After I put him straight, he said another department would have to attend to rectify the fault. He told the customer it was dangerous then promptly switched off & left, without leaving any paperwork or warning notices, leaving me to explain everything to the customer...

End result, an unhappy customer who demanded I switched back on straight away. When I declined, I got a load of abuse.

Thanks, UU.

I'm in the process of trying to find out exactly what the correct procedure is in these circumstances.

I am embarrassed that someone I called in to help my customer has upset her like this. Now I'm shouldering some of the blame.

I don't want this to happen again.

 

[Adam_151]

Bung a 30ma RCD between meter and CU and reconnect?, leave instructions for cable jointer to remove RCD and leave on site?

Insist that he makes a phone call to assertain the nature of the local network and PMEs it for you if its available?

 

[securespark]

UU Guy said he would not hang around while I did this. Also, if I did, I'd have to be there later tonight when the other gang arrive to disconnect it "otherwise they'll just reconnect what they find".

I suggested PME. His response?

"You lot make me laugh. We can't just PME it inside without grounding the neutral outside along the cable."

I knew that, and told him so.

Surly bad tempered & no bedside manner at all.

 

[Steve3948]

The supply authority are not obliged to provide an earth, but generally will if they have one available.

Treat installation as TT

 

[plugwash]

iirc while they are not obligated to supply an earth they are obligated to maintain one that they have supplied.

 

[viewer]

Where do they get these guys from? The chap down the road extended his house and needed to move the meter. This meant rerouting the supply. He has a TT supply and was told it could not be upgraded. He made all arrangements and paid the £500. The date was made for an afternoon a couple of weeks ago. At 9am the householder turned up on my doorstep. They'd arrived and were disconnecting him as we spoke. Talked to rather uncommunicative SP gentlemen to check all was OK only to find them preparing for PME. Are you sure? "Oh yes this is what we do; It will all be done without problem in the next hour." OK. Reconfigure CU to take advantage of PME. They then disappear for a while only to return and say that they cannot reconnect because "their readings are too high and they need advice". I suggested that it may be something to do with the lack of wire going down the poles and perhaps it would be easiest to put it back as TT (We'd put in and tested a new rod ready for this move). No, couldn't do that. They removed the fuse, sealed the holder and went off, saying that someone else would be along soon. Noon and house had now been without electricity for 3 hours. After 2 start ringing around to find out the situation. Eventually found someone who said that a problem had been reported and would be attended to in the next week or two! Nobody had mentioned that they had cut off the supply. At around 4 someone did call, but they knew nothing about the problem. Householder just a little irate (and cold and starving). At 6 two new characters turned up and put the fuse in, leaving householder still unconnected as tails from main switch to CU and earth still tied together in corner of meter box.
Service?

 

[Steve3948]

iirc while they are not obligated to supply an earth they are obligated to maintain one that they have supplied.

Plugwash, this is true.

 

[securespark]

What is true?

Plugwash is correct. The DNO's have no duty to provide an earth connection, unless one is already in existence, in which case they are duty-bound to maintain it. Hence UU came to sort trhis high Ze for my customer.

If you have no earth terminal, they will generally provide one for a fee.At least, my experience of UU & Central Networks has been quite positive in this respect.

 

[Steve3948]

What is true?

Plugwash is correct. The DNO's have no duty to provide an earth connection, unless one is already in existence, in which case they are duty-bound to maintain it. Hence UU came to sort trhis high Ze for my customer.

If you have no earth terminal, they will generally provide one for a fee.At least, my experience of UU & Central Networks has been quite positive in this respect.

"What is true" That DNO's have no duty to provide an earth connection.

They may be duty-bound to maintain it, however in my area on one large estate which is around 45 years old most dwellings have a ZE between 1.5 -3.0 ohms and if contacted they advise the installation be treated as a TT system.
Maybe cost of re-cabling most of the estate plays a big factor in their remedy response.

 

[Adam_151]

An't they also supposed to ensure that that any metalic sheathing of their service drops has a suitably low impedance to earth (for obvious reasons)

What i've seen certain DNOs do where PME is available, is install a head with a PME terminal and as well as making this available for the installation, also connecting it back onto the sheath to provide a low impedance earth to that