Interesting one

[New Venture!]

I went to a job where the customer wanted the wiring in his garage updated and some extra sockets added. Went to do my initial checks at the consumer unit and was surprised to find the house wasn't earthed but the consumer unit had an installation date of 2013 on it and the customer had all relevant paperwork. I  asked the customer if anyone else had been doing any work and he said yes, the "power company" had fitted a new supply as the old one was dodgy.

What has happened is they have changed what was a TNC-S supply to a TT one, without telling the householder. 

Anyone else come across this? 

 

[Tony S]

What was wrong with the original service head? What type is the new service head? What type of cable is the incoming? What did they tell the customer? (Customers have remarkably short memories when it comes to spending money.)

A photograph is worth a thousand words.

 

[Rob_the_rich]

can it be TT without an earth rod? did they supply an earth rod to make it TT? What happened to the original earthing conductor?

Is there any bonding?

Sorry for all the questions, just interested.

 

[Rob.]

If the DNO had originally provided a means of earthing, they must keep it in service or provide an alternate. 

They won't deliberately cut the earth off to a house and not say anything. 

 

[Andy™]

as above, DNO do not have to provide an earth, but if they do then it must be maintained

the only reason the DNO would disconnect it is if it was a DIY job of clamp around sheath or an earth put into an usused terminal on the side of the service head

 

[Tony S]

That is why we need a photograph.

If the cable is a PILC then an earth terminal should be provided via either a plumbed or Hepworth connection.

I’d like to know why the service head was changed. If it was CI then the cable is most likely PILC

 

[misssweden]

I went to a job where the customer wanted the wiring in his garage updated and some extra sockets added. Went to do my initial checks at the consumer unit and was surprised to find the house wasn't earthed but the consumer unit had an installation date of 2013 on it and the customer had all relevant paperwork. I  asked the customer if anyone else had been doing any work and he said yes, the "power company" had fitted a new supply as the old one was dodgy.

What has happened is they have changed what was a TNC-S supply to a TT one, without telling the householder. 

Anyone else come across this? 

How old is the property? And was the original supply definately TNC-S? In some areas with really old PILC incomers there never was an earth provided to start with. 

 

[New Venture!]

Property is a Victorian terraced house. The certification provided by the company that changed the consumer unit in 2013 states it was a TNC-S supply. Call to DNO by me to enquire as to what they understood the supply to be wasn't helpful as the person I spoke to didn't have that information but said "you really should be asking an electrician that kind of question."

I've never worked on this house before so can only go on what evidence the homeowner has provided. They didn't make any complaints re incomer but received a letter stating the supply required replacing, there would be some disruption to supply and excavation of front garden to install a new cable and access to the house was necessary.

What I know is this. The house was definitely not earthed (other than what the bonding to the water main provided) The connection to the earth terminal block was tucked in beside the consumer unit. No means of earthing has been provided by DNO. Standard grey service head/main 100 amp fuse, L/N out. 

My growing suspicion on this is with you misssweden, the 2013 certificate is wrong, it never was TNC-S but TT, and the earth readings the installer measured were via the water main. That does leave the question as to why there is a loose cable from the earth terminal block and what happened to the earth rod?

Hopefully a letter to the DNO will confirm what the supply was and should currently be. (Reason for no picture is is I always ask a homeowner if I can take a photo in their property. In this case he refused)

P.S, I hate insomnia!!!!! 

 

[binky]

DNO records tend to be somewhat incomplete these days due to cost cutting, so I wouldn't expect a great response, and to be frank it doesn't matter. If there is no supplier earth, it needs a rod,

 

[New Venture!]

I've already installed a rod as leaving the place unearthed wasn't an option. Still want to know what happened though as does the owner. Suspect he's thinking further action......

 

[binky]

wouldn't worry about it, you'll never prove anything after all this time without evidence, so I wouldn't get any further involved

 

[steptoe]

Ye, or, perhaps householders drinking buddy Bob changed the CU for him and has no idea what TT was and couldn't see an earth terminal so left it out. 

 

[kerching]

An Approved Contractor around here thought that in TNC-S.   that the C-S meant Cable Sheath

trust nobody

 

[Tony S]

Work having a private network was all TN-S, home being in a village in the middle of nowhere with OH supplies was TT. The works supplied its own estate of farms and villages, again either TN-S or TT.

I didn’t know any different, I’d read about these weird systems but they really didn’t concern me. I did try an experiment with TN-C-S at work and got my arse well and truly kicked for it.

It wasn’t until I retired I found out what a total bog-up the UK distribution system had become.

I blame Ms Sweden, cheap foreign ideas infiltrating our countries infrastructure.

 

[misssweden]

@New Venture! If there was no issues with the supply but it had still been put in for an overlay my guess it that it was very, very old. Which again makes it less likely to have been been TNC-S or had an earth provided at all. 

Work having a private network was all TN-S, home being in a village in the middle of nowhere with OH supplies was TT. The works supplied its own estate of farms and villages, again either TN-S or TT.

I didn’t know any different, I’d read about these weird systems but they really didn’t concern me. I did try an experiment with TN-C-S at work and got my arse well and truly kicked for it.

It wasn’t until I retired I found out what a total bog-up the UK distribution system had become.

I blame Ms Sweden, cheap foreign ideas infiltrating our countries infrastructure.

Are you saying I'm cheap...?  :mellow:

 

[ProDave]

An Approved Contractor around here thought that in TNC-S.   that the C-S meant Cable Sheath

trust nobody

It's scary how many plumbers think LPG is Low Pressure Gas.
 

 

[Rob_the_rich]

It's scary how many plumbers think LPG is Low Pressure Gas.
 

I can sort of understand why even Gas Safe plumbers might think that. It is almost always abbreviated to LPG (unless specifically using propane or butane), most people work on Natural Gas and never work on LPG nor are qualified to work on it. There is a bit in the Core ACS where you do a tightness test on a medium pressure meter (LPG), but you learn it, do it in the practical, then forget it. And "liquid petroleum gas" does seem to be a contradiction in terms.

 

[kerching]

Isn't LPG

LIQUIFIED Petroleum Gas?

but what would I know?..........Fricking all apparently!

 

[Rob_the_rich]

Isn't LPG

LIQUIFIED Petroleum Gas?

but what would I know?..........Fricking all apparently!

See what I mean? :Blushing

 

[Tony S]

Are you saying I'm cheap...?  :mellow:

Really, would I infer that? The last Nordic GF put me in hospital for four days.

I’m just blaming the ideas from across the water.