Good Old Delroy, he gets all the best Jobs :)

[Dustydazzler]

 

[mainline]

I'm interested what you think about a potential Neutral loss. Do you think it would be any worse than it would be on a PME setup?
To my thinking we don't know where the nearest PME point is so it's rather pot luck whether Neutral currents end up diverted. But please do share your thinking.

Let me stick to the point of you saying "he didn't make it worse" for a minute just by the glanding to the cable he made it worse
Under no circumstance should an earthing clamp (complying with BS 951 or any other type) be attached to the lead sheath of any cable. In the case of a supply cable this practice is wrong for two reasons:

• The supply cable is the property of the electricity distributor and
• The securing of the clamp to the lead sheath is likely to damage the conductor insulation of the supply cable and, with the cold-flow of the lead, the connection is liable to loosen over time. BS 951: 1999 states in Note 3 (second sentence) to its scope that 'such clamps are not intended for connection to the armour or sheath of a cable'.

In the worse cases, this practice may lead to increased risks from the hazards of fire or electric shock.

Do you agree that he made it worse ?

 

[nicebutdim]

Let me stick to the point of you saying "he didn't make it worse" for a minute just by the glanding to the cable he made it worse
Under no circumstance should an earthing clamp (complying with BS 951 or any other type) be attached to the lead sheath of any cable. In the case of a supply cable this practice is wrong for two reasons:

• The supply cable is the property of the electricity distributor and
• The securing of the clamp to the lead sheath is likely to damage the conductor insulation of the supply cable and, with the cold-flow of the lead, the connection is liable to loosen over time. BS 951: 1999 states in Note 3 (second sentence) to its scope that 'such clamps are not intended for connection to the armour or sheath of a cable'.

In the worse cases, this practice may lead to increased risks from the hazards of fire or electric shock.

Do you agree that he made it worse ?

I fully agree with your reasoning why a BS 951 clamp should not be attached to lead sheathed cables, but perhaps you could explain why his doing so on a temporary basis made the installation worse than he found it?

I get how his actions could have made it worse, but that's not the same as stating they did make it worse.

 

[timhoward]

Let me stick to the point of you saying "he didn't make it worse" for a minute just by the glanding to the cable he made it worse
Under no circumstance should an earthing clamp (complying with BS 951 or any other type) be attached to the lead sheath of any cable. In the case of a supply cable this practice is wrong for two reasons:

• The supply cable is the property of the electricity distributor and
• The securing of the clamp to the lead sheath is likely to damage the conductor insulation of the supply cable and, with the cold-flow of the lead, the connection is liable to loosen over time. BS 951: 1999 states in Note 3 (second sentence) to its scope that 'such clamps are not intended for connection to the armour or sheath of a cable'.

In the worse cases, this practice may lead to increased risks from the hazards of fire or electric shock.

Do you agree that he made it worse ?

Yes I certainly agree that it is poor practise to use a BS951 clamp on a supply cable and this could indeed be dangerous if done recklessly.
I actually think it isn't fair to dwell on this point, or say he made it worse, as it's a lose-lose situation really.
You either walk away, leaving an unverified earthing system and high ELI, and accept that fault conditions could prove fatal or start a fire.
Or do a temporary unapproved earth connection that has it's own risks, but does leave some earthing in place.
Even if you phone DNO and they say it wasn't TNS, you still have to walk away until you can fit a new earth rod.

Maybe we can agree it's a difficult situation to be in?

 

[mainline]

I never said the DNO has to decide.
Clamping the cable has no effect?
Neutral loss?

I fully agree with your reasoning why a BS 951 clamp should not be attached to lead sheathed cables, but perhaps you could explain why his doing so on a temporary basis made the installation worse than he found it?

I get how his actions could have made it worse, but that's not the same as stating they did make it worse.

The crushing of the sheath certainly won't be temporary, damage may already have been done.

The compressive forces exerted by tightening a clamp onto most types of armoured or metal sheathed cables (sufficient to provide a low resistance joint for fault or other currents to flow) are liable to cause damage to the conductor insulation and bedding. Such misuse of a clamp is a departure from Regulation 512.1.5

 

[timhoward]

For the record, that type of supply cable has two layers of steel tape, and the clamp is on the steel tape, not the lead.

 

[nicebutdim]

The crushing of the sheath certainly won't be temporary, damage may already have been done.

The compressive forces exerted by tightening a clamp onto most types of armoured or metal sheathed cables (sufficient to provide a low resistance joint for fault or other currents to flow) are liable to cause damage to the conductor insulation and bedding. Such misuse of a clamp is a departure from Regulation 512.1.5

Quoting regulations and best practice does not prove that his temporary fix left the installation in a more dangerous condition than he found it.

Don't get me wrong; I'd love to go to work every day and work only to best practice, but that's not the world we live in and sometimes calls have to be made that are less than ideal. It has already been argued convincingly that this temporary repair was, perhaps, the best that could be done on the day (subsequently it has been pointed out that the clamp was on steel, rather than lead) and I'd like something more that quotes from regs/BPG4 to back up the contention that he left the installation in a more dangerous condition than it had been previously.

 

[mainline]

Yes I certainly agree that it is poor practise to use a BS951 clamp on a supply cable and this could indeed be dangerous if done recklessly.
I actually think it isn't fair to dwell on this point, or say he made it worse, as it's a lose-lose situation really.
You either walk away, leaving an unverified earthing system and high ELI, and accept that fault conditions could prove fatal or start a fire.
Or do a temporary unapproved earth connection that has it's own risks, but does leave some earthing in place.
Even if you phone DNO and they say it wasn't TNS, you still have to walk away until you can fit a new earth rod.

Maybe we can agree it's a difficult situation to be in

For the record, that type of supply cable has two layers of steel tape, and the clamp is on the steel tape, not the lead.
View attachment 94746

I would have left as was and like westward said contact dno.

 

[Aaron b]

Let me stick to the point of you saying "he didn't make it worse" for a minute just by the glanding to the cable he made it worse
Under no circumstance should an earthing clamp (complying with BS 951 or any other type) be attached to the lead sheath of any cable. In the case of a supply cable this practice is wrong for two reasons:

• The supply cable is the property of the electricity distributor and
• The securing of the clamp to the lead sheath is likely to damage the conductor insulation of the supply cable and, with the cold-flow of the lead, the connection is liable to loosen over time. BS 951: 1999 states in Note 3 (second sentence) to its scope that 'such clamps are not intended for connection to the armour or sheath of a cable'.

In the worse cases, this practice may lead to increased risks from the hazards of fire or electric shock.

Do you agree that he made it worse ?

Most main earth's in my town are applied to lead sheaths in this way, including mine. It's before the main fuse so bs7671 doesn't apply.

 

[mainline]

Quoting regulations and best practice does not prove that his temporary fix left the installation in a more dangerous condition than he found it.

Don't get me wrong; I'd love to go to work every day and work only to best practice, but that's not the world we live in and sometimes calls have to be made that are less than ideal. It has already been argued convincingly that this temporary repair was, perhaps, the best that could be done on the day (subsequently it has been pointed out that the clamp was on steel, rather than lead) and I'd like something more that quotes from regs/BPG4 to back up the contention that he left the installation in a more dangerous condition than it had been previo

Quoting regulations and best practice does not prove that his temporary fix left the installation in a more dangerous condition than he found it.

Don't get me wrong; I'd love to go to work every day and work only to best practice, but that's not the world we live in and sometimes calls have to be made that are less than ideal. It has already been argued convincingly that this temporary repair was, perhaps, the best that could be done on the day (subsequently it has been pointed out that the clamp was on steel, rather than lead) and I'd like something more that quotes from regs/BPG4 to back up the contention that he left the installation in a more dangerous condition than it had been previously.

Most main earth's in my town are applied to lead sheaths in this way, including mine. It's before the main fuse so bs7671 doesn't apply.

And they should have been applied by the DNO not joe bloggs.

 

[mainline]

Quoting regulations and best practice does not prove that his temporary fix left the installation in a more dangerous condition than he found it.

Don't get me wrong; I'd love to go to work every day and work only to best practice, but that's not the world we live in and sometimes calls have to be made that are less than ideal. It has already been argued convincingly that this temporary repair was, perhaps, the best that could be done on the day (subsequently it has been pointed out that the clamp was on steel, rather than lead) and I'd like something more that quotes from regs/BPG4 to back up the contention that he left the installation in a more dangerous condition than it had been previously.

Maybe Del should contact Niceic, Dno etc and ask the question on whether it makes it less safe or not.
But we all know what that answer would be.
But there again he could point them to you and you could say "prove it" well done.

Whether steel wrapped or not makes, no odds except the clamp is supposed to be on the lead, so not even that was done properly.

 

[nicebutdim]

Maybe Del should contact Niceic, Dno etc and ask the question on whether it makes it less safe or not.
But we all know what that answer would be.
But there again he could point them to you and you could say "prove it" well done.

Whether steel wrapped or not makes, no odds except the clamp is supposed to be on the lead, so not even that was done properly.

So nothing to back up your statement that his temporary earthing left the place in a more dangerous condition than he found it?

Disappointing. I come here to learn and I consider asking questions to be an important part of learning. I can read regulations and best practices as well as anyone else - what I can't always do is apply them to every real world situation and in that regard I'm seemingly not alone.

 

[Pretty Mouth]

Let me stick to the point of you saying "he didn't make it worse" for a minute just by the glanding to the cable he made it worse
Under no circumstance should an earthing clamp (complying with BS 951 or any other type) be attached to the lead sheath of any cable. In the case of a supply cable this practice is wrong for two reasons:

• The supply cable is the property of the electricity distributor and
• The securing of the clamp to the lead sheath is likely to damage the conductor insulation of the supply cable and, with the cold-flow of the lead, the connection is liable to loosen over time. BS 951: 1999 states in Note 3 (second sentence) to its scope that 'such clamps are not intended for connection to the armour or sheath of a cable'.

In the worse cases, this practice may lead to increased risks from the hazards of fire or electric shock.

Do you agree that he made it worse ?

Just in case anyone was wondering, here is the article that @mainline cut-and-paste his answer from:

Earthing clamps not to be used on cables

Earthing clamps must not be used on paper-insulated/lead sheathed or steel wire armoured (swa) cables.

www.voltimum.co.uk

 

[Pretty Mouth]

Most main earth's in my town are applied to lead sheaths in this way, including mine. It's before the main fuse so bs7671 doesn't apply.

I see this so commonly around here that I have to assume that it was standard practice at one time

 

[mainline]

So nothing to back up your statement that his temporary earthing left the place in a more dangerous condition than he found it?

Disappointing. I come here to learn and I consider asking questions to be an important part of learning. I can read regulations and best practices as well as anyone else - what I can't always do is apply them to every real world situation and in that regard I'm seemingly not alone.

 

[UNG]

Bit difficult to get back on the tools if their main job is as a College lecturer, don't you think? as all of the guys that taught me were full time Lecturers

Most of the lecturers at the college I went to were electricians who had moved into teaching so I don't see why it would be a problem to do a month or two back on the tools every 5 years or so their teaching was relevant to current methods and materials