earth point / Suppliers Earthing conductor on a TNS installation

[MK43]

Gentlemen, I am new here, I was a member of the local Electrician forum a few years back. I am a 75-year-old Electrician, I have worked in the electro-mechanical and electronic industry, I have the 238001 and 239101 city & Guilds and I have been service engineer, service manager, production and electronics manager since 1970 and electrician since 1993.

My topic is:

What would you do, if you find that in a TN-S system the earth clamp on the supplier’s mains armoured cable providing the earth conductor to the installation, has been placed on top of the insulating cloth. Have you seen this? of course we all have.

I always check the Ze and whether it is or not okay (in this case it was not), I put a new earth clamp on a bare part of the mains cable, on the lead, near the head.

Am I right or wrong?

In the case I am referring to, I attempted to loosen-up the clamp to be able to remove it, but my screwdriver when thru the armoured cable like a knife on butter and the obvious happened, a little explosion.

The lead was damaged, was wafer thin, the cloth was covering the damaged area and the clamp was placed exactly over it.

The supplier complained I was negligent, and send me an invoice of £1473.10

Would you fight it? Or put it down to experience and never do it again.

If you decide to fight it how would you go about it.

I have never been a member of any association.

Any suggestions or criticisms will be welcomed. I have  taken pictures if you want to see them.

Thank you.

 

[binky]

I think you will struggle to fight this as you are not suppossed to mess with DNO equipment. THe correct action would have been to contact your DNO and register a call out for lack of earthing as a dangerous condition, in which case you would probably have got it fixed free of charge in a couple of hours. However, I you could try argueing the price is excessive - seems they are charging as a new supply.

 

[Andy™]

quite simply you damaged their equipment, you pay.

simple solution would have been to phone DNO and report the earth not working. they are obliged to maintain it if they supplied one so they would have fixed it FOC

 

[Murdoch]

Write the cheque and put it down to experience.

 

[kerching]

THat cable is NOT your responsibility 

interfering with DNO equipment is illegal

'clamps'.....CPS are only to be fitted by DNO .(?even though we see 951s fitted sometimes)

pay the £1473.10 and treat it as a lesson learned...it's cheaper to tHan a prosecution and/or funeral/hospital trips to burns unit

obviously only my personal opinion

 

[Evans Electric]

I  recently had my supply cable re-sited  to a meter box outside  by the DNO,    a tee joint and 2 mtrs  of cable  @ £850 .  It would have been £1200    had I not done the digging .  

As Binky says ,   they just applied the cost of a new service  .  Or they may be actually fitting a new service and charging you .  

The way to go would have been to get the DNO in to do the earth    .     If they are charging you to  come and fit an earth connection , or PME  the supply  I would challenge the cost , but as said , it was your fault  I'm afraid .    I've seen constant force earth springs fitted  before now  , not that I'd ever do such a thing of course .     

 

[kerching]

Is it just me or do the constant force/cps springs seem a bit weary?

ive used loads on SWA joints up to 400mm and I've never convinced

 

[Evans Electric]

They seem OK on the lead sheath  of the older domestic supplies ...so I'm told  .    I believe it's all the DNO will fit now  ,   no more plumbing  a connection on  apparently.  

I've never used any on joints . 

 

[Tony S]

Hepworth clamps and constant pressure springs are OK on lead, just don’t use BS951 clamps. For SWA I’d rather use a split support ring and a jubilee clip.

As for the CP springs on PILC, they have a personal vendetta against my fingers.

 

[MK43]

What do you do when you are asked to replace a fuse box and you find the earth clamp to be fitted on top of the cloth on the incoming TN-S supply, do you use the same earth point for your new fuse box?

 

[MK43]

I think you will struggle to fight this as you are not suppossed to mess with DNO equipment. THe correct action would have been to contact your DNO and register a call out for lack of earthing as a dangerous condition, in which case you would probably have got it fixed free of charge in a couple of hours. However, I you could try argueing the price is excessive - seems they are charging as a new supply.

Thank you Binky, I was not trying to add a new earth point, I was trying to improve the quality of installation and get a better, lower Ze reading, because no professional electrician would put earth clamp on top of the cloth. We sand-paper the copper pipes before we put the earth clamp. I know I was unlucky, but arent they suppose to maintain ageing installation? I believe the price was that high because they could not disconnect their supply to do the repair, they had to excavate outside the shop to install an isolator , But why do I have to pay for this. Never mind, I will take your advice and pay the money and lets say we all learnt something. If only we had a good solicitor!

Thanks for taking the time to reply Binky.

 

[binky]

you are welcome. Good intentions don't cut the mustard unfortunately, and as a large company, with large company overheads the bill will be high. 

 

[Andy™]

Thank you Binky, I was not trying to add a new earth point, I was trying to improve the quality of installation and get a better, lower Ze reading, because no professional electrician would put earth clamp on top of the cloth. We sand-paper the copper pipes before we put the earth clamp. I know I was unlucky, but arent they suppose to maintain ageing installation? I believe the price was that high because they could not disconnect their supply to do the repair, they had to excavate outside the shop to install an isolator , But why do I have to pay for this. Never mind, I will take your advice and pay the money and lets say we all learnt something. If only we had a good solicitor!

Thanks for taking the time to reply Binky.

ESQCR says if they provide an earth they must maintain it, and they will. you just needed to phone them, then they would have sent someone to fix it....

but instead you tampered with their installation and broke it. they cannot just turn off the entire street to fix it, they will often have to go back a bit, dig a hole, disconenct the cable (live), then either replace or repair, then reconnect to the live main. @misssweden will know far more about what would be required than we do

solicitor wouldnt make any difference, you tampered with someone else property and broke it, why should everyone else have to pay instead of you?

 

[ProDave]

If there was a fault on the DNO's earth clamp, you should have phoned the DNO and they should have repaired it.

 

[ProDave]

You phone the DNO and report the fault and they will come and fix it.  Say it's dangerous and they usually come the same day.

Wait until the new CU is connected and they can replace the missing fuse seal as well (which was obviously missing)

 

[Andy™]

phone DNO and get them to fix it. or you could try it yourself and damage the cable then try and ask the same thing over and over and hope you get a different answer

 

[Blue Duck]

What was the ze? 

Have had a quite few damaged / corroded earth connections in the past and UKPN have always come out and replaced them by fitting a Hepworth clamp or PME 'ing the supply.

 

[Doc Hudson]

What do you do when you are asked to replace a fuse box and you find the earth clamp to be fitted on top of the cloth on the incoming TN-S supply, do you use the same earth point for your new fuse box?

Before doing any alterations temporary or permanent, wiring regulations states that we have a duty to verify the condition of the incoming supply and its earth arrangements. If you find the integrity of the earth is inadequate then you would address it further with the owner of the earth connection. If its a TT you would discuss improvements with the client. If it is TN then you would contact the owner of the supply cable (DNO). You would only then proceed with any remedial work to the earth arrangements, once you have permission from the respective owner. Once you have got an electrically sound supply earth, you can then undertake the alterations originally requested.

Doc H. 

 

[Doc Hudson]

I have merged your two threads as they clearly relate to the same topic and answers to either could well be very similar. It saves cluttering the forum with several duplicate posts.

Doc H.

 

[misssweden]

Unfortunately for you @MK43 you’ll just have to put this one down to experience and pay the money. The cost of a team of jointers and a digging gang and the time it takes to excavate, do an isolation cut, do repairs/run a new service in and put it all back together plus reinstatement quickly adds up. 

Next time just call the DNO, an issue like yours is normally a quick and easy fix.