Taking cables from a house to a garage

[spinlondon]

I do not disagree with you that electrically this should make naff all difference but this comes down to arse covering. At the end of the day if you install a rod to a MET with a TN Earth too then that is not covered by the BRB so (as I mentioned above) no protection by 7671. If IET want to ammend 7671 to take into account what they said then thats fine but I bet you won't get anything in writing form DNO about that.

Strange that you say you won't get anything in writing from a DNO about that, when I have already provided you with something in writing to that effect.

 

[steptoe]

Now who doesn't know what they're talking about - the two most common domestic systems in the UK are TN systems:TN-S and TN-C-S

I think your getting confused with TN-C, which is illegal in the UK

TN is not permitted in a premises in the UK

For anyone interested, I've spoken to the DNO (Scottish Power) and I've spoken to the IET (the big red book people)Neither of them can see anything wrong with connecting a rod to the MET as an additinal reference to earth when PME conditions apply.

The DNO said it doesn't affect their setup at all and the IET said if the DNO are alright with it then there's no reason why you can't.

Now, I think, the case is finally closed.

NO one stated PME conditions were met, you have assumed PME when all the information you have is TNCS

TNCS IS NOT ALWAYS PME

but

PME NEEDS TO BE TN

 

[spinlondon]

Steps, to be honest with you. Yore insitance on making statements on what is allowed or what is dangerous is wearing a little thin.

So far you haven't supplied any evidence to support your claims.

To my mind it's time to put up or shut up.

Produce some evidence to support your claims.

 

[ianmacd]

Strange that you say you won't get anything in writing from a DNO about that, when I have already provided you with something in writing to that effect.

No you haven't and you are not a DNO anyway.

 

[PBC_1966]

AFAIK TNCS can only be supplied if the network is PME

That's certainly how it used to be, as in my references above. Steptoe is saying (I think) that it is not always the case now (we know that TN-C-S and PME are not the same thing by definition; the question is whether DNO's are allowing TN-C-S without the network being PME).

so I do not see how an lead sheath earth can not be a neutral as into the cutout it should still be a combined PEN and seperated there.

My point about the concentric was just that it's not necessarily applicable to the basic point being debated, since a supply from a PME network to an installation using TN-C-S could just as easily be individual overhead conductors.

I'm sure I said above that I am not debating the electrical benefits BUT the fact that the regulations we should be following to allow ourselves to be protected by 7671 if we install a rod.

Fair enough, but I just find it impossible to ignore basic electrical principles because of what BS7671 may or may not say. Not that I accept that there is anything in there anyway which says you can't have an earth electrode on the consumer's side of a TN-C-S system.

Also, doesn't the BRB say that pipes are not earth electrodes (although they do introduce an earth potential)?

Since the 14th edition the Regs. have said that they are not to be used as the required earth electrode, but as I said earlier, the laws of physics aren't going to change just because the IEE decided to make that rule. Whether you, I, or the entire IEE/IET committee likes it or not, a buried metallic pipe is going to behave as an earth electrode. The only reason for that change in the 14th edition was to cover the possibility of metallic piping being replaced with plastic, not because the metallic piping itself was not an effective earth electrode.

TN is not permitted in a premises in the UK

What do you think TN-S and TN-C-S are then? What do you think the "N" part of TN stands for?

TNCS IS NOT ALWAYS PME

Nobody is disputing that.

butPME NEEDS TO BE TN

Haven't you just tried to say that TN is not permitted? And a PME distribution system taken alone (without the consumer's installation) is neither TT nor TN, since the designations refer to both the method of earthing of the source of power and the method of earthing at the installation.

The LV network where I live is entirely PME now, but there are still large numbers (a majority I would say) of houses which are TT.

 

[spinlondon]

No you haven't and you are not a DNO anyway.

I quoted a copy of the LEB requirements for PME connection, Regulation 9.7.

The fact that you decided to ignore my post is your problem.

 

[PBC_1966]

Steps, to be honest with you. Yore insitance on making statements on what is allowed or what is dangerous is wearing a little thin.So far you haven't supplied any evidence to support your claims.

To my mind it's time to put up or shut up.

Produce some evidence to support your claims.

I second the motion!

 

[ianmacd]

I quoted a copy of the LEB requirements for PME connection, Regulation 9.7.The fact that you decided to ignore my post is your problem.

Is that the one that relates to street lights?

 

[ADS]

I give up - I speak to an engineer at the DNO and the technical help (specifically for electrical installation) at the IET and what do you say - I want it in writing!!

If I got it in writing, you'd want it off the PM.

If I got it off the PM, you'd want it off the Queen!

Unbelievable!!

Thing is, no one against it has given us anything in writing to say you (legally)can't do it.

No one has offered anything in writing to explain why you (electrically) can't do it.

And Steps, I can't believe you've made the exact same statement again after being pointed out that you're wrong - of course you can have TN systems in the UK - it's mentioned on near enough every other page in the regs.

 

[ianmacd]

I give up - I speak to an engineer at the DNO and the technical help (specifically for electrical installation) at the IET and what do you say - I want it in writing!!If I got it in writing, you'd want it off the PM.

If I got it off the PM, you'd want it off the Queen!

Secretary of state will be fine .

Unbelievable!!

Thing is, no one against it has given us anything in writing to say you (legally)can't do it. I have given loads of regs against it and debunked ALL the regs posted for it.

No one has offered anything in writing to explain why you (electrically) can't do it. Not sure such an argument exists.

And Steps, I can't believe you've made the exact same statement again after being pointed out that you're wrong - of course you can have TN systems in the UK - it's mentioned on near enough every other page in the regs.

Me in RED

 

[Dambo]

Wowzers, what a debate!

 

[ADS]

I have given loads of regs against it and debunked ALL the regs posted for it.

Okay, I must have missed that:|

Give us the reg number then - just one will do

 

[ianmacd]

542.1

 

[ADS]

I'm guessing you are referring to 542.1.1

The main earthing terminal shall be connected with earth by one of the methods described in regulations 542.1.2 to 542.1.4, .........

I do understand how you are reading it

But I take that to mean it must be connected by one of them (at least) - in other words all installations must be connected to earth.

Not that it can only be connected to one of them.

As they confirmed on the phone that it isn't a problem, I think I'll read it my way - so still no reg saying you can't rod a TN (PME or not) installation.

 

[ianmacd]

If you want to believe you are still performing installations to 7671 by putting in an earth rod then that's up to you but don't come crying to us when you get your library time in prison after someone is killed and you have found to not have complied with 7671 (whether it was the cause of the accident or more likely not you will be the scapegoat).

Me? I would prefer to stick to 7671. If you really want to know what was meant by that then don't call some random person at the iet but get in contact with the group who wrote that section.

Incidentally, what will you call your new earthing system as PME is rodded at the PEN not the PE so its not TNCS anymore?

 

[spinlondon]

Is that the one that relates to street lights?

It is contained in guidance for street furniture and lighting.

However the actual Regulation (9'7) I quoted refers to: " Roadside and other housings accessible to the public (e.g. public telephones, pedestrian crossing bollards, ticket machines, cable TV supply points)."

It is their Regulation 10 that refers to: "Street lighting columns." Which I have not quoted.

Unfortunately, I only had access to Regulations that were rellevant to Street lighting and other furniture.

 

[steptoe]

Steps, to be honest with you. Yore insitance on making statements on what is allowed or what is dangerous is wearing a little thin.So far you haven't supplied any evidence to support your claims.

To my mind it's time to put up or shut up.

Produce some evidence to support your claims.

eawr reg16

That's certainly how it used to be, as in my references above. Steptoe is saying (I think) that it is not always the case now (we know that TN-C-S and PME are not the same thing by definition; the question is whether DNO's are allowing TN-C-S without the network being PME).so why do you keep assuming it is?

My point about the concentric was just that it's not necessarily applicable to the basic point being debated, since a supply from a PME network to an installation using TN-C-S could just as easily be individual overhead conductors.

used to be illegal for TNCS unless rodded at entrance to building

Fair enough, but I just find it impossible to ignore basic electrical principles because of what BS7671 may or may not say. Not that I accept that there is anything in there anyway which says you can't have an earth electrode on the consumer's side of a TN-C-S system.

Since the 14th edition the Regs. have said that they are not to be used as the required earth electrode, but as I said earlier, the laws of physics aren't going to change just because the IEE decided to make that rule. Whether you, I, or the entire IEE/IET committee likes it or not, a buried metallic pipe is going to behave as an earth electrode. The only reason for that change in the 14th edition was to cover the possibility of metallic piping being replaced with plastic, not because the metallic piping itself was not an effective earth electrode.

What do you think TN-S and TN-C-S are then? What do you think the "N" part of TN stands for?

we are not talking about the distribution, but the installation

Nobody is disputing that.

Haven't you just tried to say that TN is not permitted? And a PME distribution system taken alone (without the consumer's installation) is neither TT nor TN, since the designations refer to both the method of earthing of the source of power and the method of earthing at the installation.

we are concerned with the installation, not the distribution

The LV network where I live is entirely PME now, but there are still large numbers (a majority I would say) of houses which are TT.

sensible

I second the motion!

I give up - I speak to an engineer at the DNO and the technical help (specifically for electrical installation) at the IET and what do you say - I want it in writing!!If I got it in writing, you'd want it off the PM.

If I got it off the PM, you'd want it off the Queen!

Unbelievable!!

Thing is, no one against it has given us anything in writing to say you (legally)can't do it.

No one has offered anything in writing to explain why you (electrically) can't do it.

And Steps, I can't believe you've made the exact same statement again after being pointed out that you're wrong - of course you can have TN systems in the UK - it's mentioned on near enough every other page in the regs.

NO its not, tell me a reg that permits TN in a normal domestic installation?

you must have S on your install.

in case you are still wondering why I havent quoted any of BS7671 to you its because I work to the LAW, not an opinion of it, the fact of it,

ignorance or trying to blame someone else's advice is NO defence in law.

you MUST adhere to reg16, note also reg29(IIRC), it explains it a bit more, and nowhere does it say you can blame the authors of BS7671.

well, your honour, on page 59, part 5 it said it was OK to join the earth to the clothes line will not wash when hilda is on a stone slab.

 

[steptoe]

It is contained in guidance for street furniture and lighting.However the actual Regulation (9'7) I quoted refers to: " Roadside and other housings accessible to the public (e.g. public telephones, pedestrian crossing bollards, ticket machines, cable TV supply points)."

It is their Regulation 10 that refers to: "Street lighting columns." Which I have not quoted.

Unfortunately, I only had access to Regulations that were rellevant to Street lighting and other furniture.

and therefore totally irrelevant to this discussion

 

[spinlondon]

Sorry Steps, but are you refering to this Regulation from EAWR?

"Persons to be competent to prevent danger and injury

16. No person shall be engaged in any work activity where technical knowledge or experience is necessary to prevent danger or, where appropriate, injury, unless he possesses such knowledge or experience, or is under such degree of supervision as may be appropriate having regard to the nature of the work."

How exactly does that Regulation relate to our discussion?

As for your other comment, why are Regulations that pertain to PME connections irrelevant to this discussion exactly?

Are you suggesting that a Regulation that is relevant to street lighting, cannot be relevant to other installations?

 

[steptoe]

Sorry Steps, but are you refering to this Regulation from EAWR?"Persons to be competent to prevent danger and injury

16. No person shall be engaged in any work activity where technical knowledge or experience is necessary to prevent danger or, where appropriate, injury, unless he possesses such knowledge or experience, or is under such degree of supervision as may be appropriate having regard to the nature of the work."

How exactly does that Regulation relate to our discussion?

As for your other comment, why are Regulations that pertain to PME connections irrelevant to this discussion exactly?

Are you suggesting that a Regulation that is relevant to street lighting, cannot be relevant to other installations?

Im suggestion that a reg relevant to street lights is not relevant to bedroom lights.

Im also suggesting that anyone contemplating(never mind doing) connecting an earth electrode direct to the MET of a domestic TNCS system in the UK is unable to comply with reg16 of EAWR.

actually Im not suggesting it, that, IMO is a fact.

and Im am getting fed up trying to explain the simple basics of earthing to incompetent people that its scary just thinking about the state some peoples houses must be getting left in.