An interesting read

[andrew1210]

To summarise - As SP see it "I *should* (but no drawings) be TT

BUT - All 150 houses (wired in 1979 by council as all council at that time) wired like in pics. . .

Yes, this is really interesting and quite exiting, OK I don't get out much

Would like to see the DNO/network guys comments on this.

Me too apparently, although frustrating, I am actually finding it quite amusing watching all these SP folk baffled! lol

I overheard the phone call between INQ when they were here and an SP contact.... "So you're saying you don't know as there is no drawings..." long silence......... "Well not that theres no drawings, there would have been originally, we just can't find them" lmao :L

 

[sparkticus]

To summarise - As SP see it "I *should* (but no drawings) be TT

BUT - All 150 houses (wired in 1979 by council as all council at that time) wired like in pics. . .

Yes, this is really interesting and quite exiting, OK I don't get out much

Would like to see the DNO/network guys comments on this.

Me too apparently, although frustrating, I am actually finding it quite amusing watching all these SP folk baffled! lol

I overheard the phone call between INQ when they were here and an SP contact.... "So you're saying you don't know as there is no drawings..." long silence......... "Well not that there no drawings, there would have been originally, we just can't find them" lmao :L

I'm based in the Bath area. Today I called Western Power to find out two things
1) Was a property available for PME?
2) What is the existing cut-out fuse rating?

They did not know the answer to either question and charge £42 + VAT to come out, look at it and let me know. Oh and unless it's an emergency that will take approximately 3 weeks

 

[andrew1210]

sparkticus - If only you had been up here in Scotland, where a "class C" emergency takes 3 months to get round to delaing with, and 6 months total from original phone to..... oh wait, we've not actually done anyhting yet!

 

[sparkticus]

sparkticus - If only you had been up here in Scotland, where a "class C" emergency takes 3 months to get round to delaing with, and 6 months total from original phone to..... oh wait, we've not actually done anyhting yet!

Yes, in general I found DNO engineers to be very competent/knowledgeable and there are a few regulars on the forum. I trust they won't mind me saying that the front-desk/admin people are somewhat less impressive

 

[JohnW2]

Just clarify where I was going because on reflection I badly worded the above. Are we looking at an illegal PME here? PMEd by mistake in good faith way back back when? Yes PME at the cut-out but was the neutral evaluated for PME before it was done? ...

I think you're writing 'PME' when you probably really mean TN-C-S.

Given that Andrew says that the DNO think it should be TT, but all 150 houses have been wired per his pics (with an earth coming out of the service head) is not the 'worst case interpretation' that this could possibly be TN-C-S without PME - which is a dangerous arrangement which, as far as I am aware, should never happen.

We need some DNO experts/referrees here, I think!

Kind Regards, John.

 

[sparkticus]

Given that Andrew says that the the DNO think it should be TT, but all 150 houses have been wired per his pics (with an earth coming out of the service head) is not the 'worst case interpretation' that this could possibly be TN-C-S without PME - which is a dangerous arrangement which, as far as I am aware, should never happen.

We need some DNO experts/referrees here, I think!

John, yes you have put that in much better/clearer terms than I did.
Now as you have said I believe I understand that a TT system can not be converted to TN-C-S without a full evaluation of the entire supply from sub-station to property. Any breakers in Neutral to be removed and neutral bonded to earth multiple times on rout. What if this was an old TT system "accidentally" converted to TN-C-S without anyone checking anything outside the property?

Again, my knowledge of DNO networks is basic. It's something I would like to learn much more about so I may be basing my suspicions on incorrect ideas.

 

[andrew1210]

Well the most I can say is that yes I assume all the houses up here are wired as mine, as I have checked 6 of friends/family (spread across 3 different streets in our area) and all are wired like mine!

Also, my gran lives around the corner from me, and I had a much closer look there, identical setup. Deffinately no local Earth spike.

 

[matt1e]

Hi John, Sparticus and Andrew
just in from pub and haven't had A good read through but apologies as I think I have been confusing you with the terminolgy I've been using
when I refer to the "MET" I (rightly or wrongly) always mean the earth terminal at the cutout
I always refer (rightly or wrongly) to the main earth terminal in the CU as just the "CU or DB earthing terminal"
Hope that clears it up A bit

Are we looking at an illegal PME here? PMEd by mistake in good faith way back back when? Yes PME at the cut-out but was the neutral evaluated for PME before it was done?

they would/should have fitted earth stakes at several pole positions and ran the neutral down the poles to them when they converted to PME I would have thought

 

[JohnW2]

Hi John, Sparticus and Andrew .... just in from pub and haven't had A good read through but apologies as I think I have been confusing you with the terminolgy I've been using. when I refer to the "MET" I (rightly or wrongly) always mean the earth terminal at the cutout. I always refer (rightly or wrongly) to the main earth terminal in the CU as just the "CU or DB earthing terminal". Hope that clears it up A bit

Ah - that explains most of the confusion As for 'rightly or wrongly', I have to say that I think you are a bit out on a limb with that terminology. 'MET' usually refers to an 'earth block' to which main protective bonding and CU etc. are connected - or, if there is no such block, the earth bar in the CU itself.

they would/should have fitted earth stakes at several pole positions and ran the neutral down the poles to them when they converted to PME I would have thought

As I recenly wrote, they certainly should have done that and, if they didn't ('the worst case interpretation') the OP could be dealing with TN-C-S without PME - which, if the case, would surely be diabolical and dangerous. If any of the DNO folk who have been involved had considered that possibility, they surely would have got their finger out much more rapidly than they have; one might have hoped that finding TN-type service head arrangements on an installation which they believed should be TT would have caused some alarm bells to sound!

Kind Regards, John

 

[bernardgreen]

We need some DNO experts/referrees here, I think!

From what I am reading I think the more (urgent) need for DNO experts is up there with Scottish Power or who ever manages(?) the system where Andrew lives.

 

[matt1e]

when I refer to the "MET" I (rightly or wrongly) always mean the earth terminal at the cutout. I always refer (rightly or wrongly) to the main earth terminal in the CU as just the "CU or DB earthing terminal". Hope that clears it up A bit

Ok john I perhaps should have said "at the cutout position"
But in my defence I thought it would be pretty much clear from the drawing I did to what I meant


Matt

 

[JohnW2]

Ok john I perhaps should have said "at the cutout position" But in my defence I thought it would be pretty much clear from the drawing I did to what I meant

Yes, if you had said that, then I (for one) would not have got confused. However, I also accept that I should have looked at your drawing more carefully (and also should have noticed that the pics didn't show a 'MET' outside of the CU) - in which case I would at least have asked you what you meant by 'MET', and thereby again resolved the confusion.

In the situation the OP has (with no 'earth block'), I think that most electricians (and books) would call the earth bar in the CU the 'MET'.

Kind Regards, John.

 

[andrew1210]

Just another wee quick question,

Aside the problems we are having, regarding the cutout, (shown on page 6 for anyone who hasn't seen the pics!) the black cabled feed to next door was re-terminated on Mon as it was disconnected it for testing etc. Would you say the neutral connection is safe? Maybe i'm being daft, but the exposed copper is not something I'm entirely comfortable with!

Thanks Again, the knowledge you pick up on this forum is unbelievable, an engineer said I sounded like a spark the other day when liaising basically what was said here!

 

[EFLImpudence]

What are those (looks like two) grey sheathed cables which come out of (or go into) the CU and run around the meter into the hole in the wall?

 

[ban-all-sheds]

they would/should have fitted earth stakes at several pole positions and ran the neutral down the poles to them when they converted to PME I would have thought

But they didn't convert it to PME, or even to TN-C-S, it appears.

They think it's a TT supply.

I think I recall, (but can't be rsed to read through 8 pages to confirm) that all of these houses were built at the same time?

By the same developer?

Hands up anyone who would like to claim that there could be no way that what happened was simply that the builder used a bunch of incompetent numpty electricians who wired everything as TN-C-S because they were incompetent numpties?