Upgrade of fat braid main earth conductor

[SW1970]

Hi folks, about to do a domestic PIR and observed during survey that the main earth conductor is flat braided copper. Didn't measure but from photo it looks either 6 or 10mm2 CSA. Assuming that Captain Adiabatic tells me it's inadequate, when I call on supplier to upgrade, will they most likely replace with larger braid or put on a new sheath clamp with appropriate round cable? Many thanks, SW

 

[SW1970]

Oops not sure where "fat braid" came from... It was an erroneous fat.

 

[La Poste]

Got any pictures?

 

[SW1970]

Here you go...

 

[i=p/u]

well sw1970 all i know its tns sytem and should have 16mm earthng conductor.

 

[i=p/u]

dont thank me now for that useful info.. im here to help

 

[Knobhead]

Did you get the measurements of it?

6	12.0	1.0	0.20
10	15.0	1.5	0.20
16	19.0	2.5	0.20
25	25.0	3.0	0.20
35	25.0	4.0	0.20
50	30.0	5.0	0.20
70	32.0	6.0	0.20
95	37.0	6.0	0.20
120	45.0	6.0	0.20
150	50.0	8.0	0.20
200	50.0	10.0	0.20

Nominal area (mm²)Width (approx. mm)Thickness (approx. mm)Wire diameter

 

[SW1970]

No but it's either 6 or 10mm2. But back to my question, does the DNO replace with new clamp and round cable, or simply fit larger braid?

 

[malcolmsanford]

It's the DNO property mate and all you can really do is call them, but I know that if you have a good Ze value for it they will do nothing.

If I got a good Ze value, then I would basically leave it alone, You could note it, but it's not part of our installation so as long everything the customer side is ok then your good.

It may even be an old DIY TN-S done by a bygone sparks

 

[malcolmsanford]

well sw1970 all i know its tns sytem and should have 16mm earthng conductor.

Oh dear oh dear oh dear.

 

[oxocube]

well sw1970 all i know its tns sytem and should have 16mm earthng conductor.

dont thank me now for that useful info.. im here to help

Why should he thank you for giving incorrect advice, don't forget to thank me for correcting you.

 

[i=p/u]

cheers oxo il look at that pic again then, this is the response i want

 

[i=p/u]

isit just a water pipe

 

[malcolmsanford]

no look again and try this time reading it

 

[SW1970]

i=p/u, no, it's not just a water pipe. Why would an electrician post a picture of a supply cable with an earth strap around it and ask what the DNOs approach would be if it was a water pipe? Let me quote you something:

"aint easy isit, dealing with cable pullers like myself. ive no expierience with testing so just done R1+R2 with multimeter"

A 16mm2 earthing conductor is not strictly required if the adiabatic equation allows it. But, I had not appreciated, per malcolm's comment, that this may be a DIY TN-S, in which case, the DNO would state they are not supplying an earth. What would happen then if there was an incident (this property has no RCD). If I'd done a job and walked away, yes, I probably be liable.

One needs to be very careful giving technical advice or commentary on a forum like this. Because a DIYer, an apprentice or someone with little experience might (foolishly) take the advice and then go and kill themselves or someone else.

 

[i=p/u]

old news that sw1970, thats why the forum has put at top of screen, this an open forum , do not take informations as facts or something like that. theres loads of stuff and there is everydaay that is wrong and in an open forum, so what is it lol il look again chill man..

 

[malcolmsanford]

i=p/u I was told a long time ago

"Speak when you spoken to, listen when men speak as you may learn something, if we want your advise it won't be asked for until it is worth something"

That as stood me in good stead, and if you actually do it it may do you some good.

Think all of us on here are quite happy to help you with your problems, and sometimes your home spun humour is quite amusing, but when you start to give advice when your not capable of doing it, then I think it is wise to point this out to you.

You lads I'm afraid missed out on what I had and that was an old fart like me telling you as I was told above, this is why SW1970 asked a question on something he had never seen, and Tony and others who had seen it all before have tried to help him, and we are glad we can as that is how it should be, passing on our knowledge and experience to you lads.

Now son sit in the corner or make the tea, and the broom don't push itself around, and perhaps listen and ask us and we will tell you, honestly we will

 

[i=p/u]

ayee i know im full on silly sparks sometimes , but its just i dont know and if i guess , which is all i done, i stand to be corrected, now chin up you aint that old

 

[i=p/u]

wonder what that pics of??

 

[malcolmsanford]

Good lad ..............make it an ask by all means, but try not to make it look like advise as SW say some will think it is right .................and wrong advise taken could cause a serious problem .

 

[Knobhead]

I’ll just add that braid will give a better connection than any modern method.
Personally if I’d had done it would be soldered to the lead, but I’m an old fart as well!
It’s lovely stuff to work with if you can solder to make the termination.
Another interesting point is it’s current carrying capacity, much higher that a normal stranded conductor. I’ll leave it to you to look for the ratings, I wouldn’t bother with the BRB though.

 

[Engineer54]

Couldn't of put any better than that Tony!!

If you want an analogy of sorts, think about welding cables, multi-fine wire stranded cable have a far higher current carrying ability than your typical building wire type cables.

 

[mechelec]

FYI the braid is a hepworth bond and they are still used today. It is DNO property and complies with their regulations. you need to worry about the main earthing conductor size to the earth terminal supplied by them. PDF attached

View attachment hepbond.pdf

 

[La Poste]

It's probably a silly question but how much risk is there in soldering an earth cable onto the lead sheath of a TN-S cable?

I mean I know how to solder but is this a really bad idea to think about doing this to a DNO's cable?

Thanks.

 

[GLENNSPARK]

old news that sw1970, thats why the forum has put at top of screen, this an open forum , do not take informations as facts or something like that. theres loads of stuff and there is everydaay that is wrong and in an open forum, so what is it lol il look again chill man..

Look mate...your not on your own here....on occasions i have also got things wrong...and quite rightly been pulled up about it. A little constructive critisism from time to time is good for ones self....yes your quite right this is a public forum which is why...in a kind of way we have to be ultra carefull as to the info we give and the accuracy of said info....Take it as a compliment that forum members like Mr Sanford and others are taking an interest in your progress but remember....many forum members are very much more experienced than either you or i so sometimes you just have to shut up, take the flak and get on...........

 

[Knobhead]

It's probably a silly question but how much risk is there in soldering an earth cable onto the lead sheath of a TN-S cable?

I mean I know how to solder but is this a really bad idea to think about doing this to a DNO's cable?

Thanks.

It’s something you don’t do if you haven’t been trained to do it!

 

[La Poste]

The thing is if DNO's don't want to do it or can't be bothered to come out and fix a bad TN-S connection how do you improve a TN-S lead sheath earth connection?

Are there special clamps out there?

If soldering is not to be used what other methods are there because I hear that DNO's don't like to fix it they like to sell you PME instead.

 

[Knobhead]

Read mechelec’s post

 

[La Poste]

They look perfect, just the job.

 

[mechelec]

They look perfect, just the job.

The DNO will maintain a supplied earth terminal, this includes fitting a new hepbond if required. if the installation is TN-S they will leave it TN-S and if it is PME they will maintain it if you have a bad Ze. Most will not supply an earth terminal if one has never been supplied then you will have to pay for the installation to have PME earth terminal.
Do not under any circumstances interfere with the DNO cable or equipment. If it faults you will end up having to pay for the damage you have caused the same as if you hit a cable whilst digging in the street. On top of the cost is the fact you will be injured. Believe me if you fit a clamp around a paper lead cable and do it wrong it will fault and the protection on the supply cable will be up to 400A with a designed clearance time of 5 seconds.

 

[La Poste]

Thanks for that warning.

I just wonder what they will say about this when they see it.

Not fitted by me and apologies for hi jacking the thread.