TN-S Code Two??

[gap30]

Was talking to a friend earlier about the number of installs i have been to recently with no main earth, he told me that the NICEIC are now saying any TN-S with no soldered connection (earth clamp on metal sheath etc) should be made into a TT and Code 2 it, bear in mind this is for a large social housing company. I recently discussed this myself on my 12 month NICEIC renewal and was told roughly the same thing. Anyway i have reported this several times to Scottish Power on some consumer unit upgrades, when i have spoken to guys from Scottish Power about this they are happy with an earth clamp in most cases.

My friend reckons the NICEIC are soon going to insist on this.

I always thought another way around this was to use a Hepworth clamp (have never done so myself tbh)

Thoughts anyone?

 

[gap30]

Care to explain please

Really?

 

[Andrew Youll]

FFS!!.....do you really think the DNO would fit a 951 clamp???.....it would have been fitted by a sparks and not the DNO.

I work in a Northern Powergrid Area, we were advised on our last scheme assessment to note down BS951 clamps on EICRs and to contact NPG of situation to rectify, got a letter in the post to the office saying NPG no longer fit BS951 clamps and do not replace BS951 clamps if there is a sound electrical connection.

The letter seemed to imply they did fit them once upon a time.

 

[Engineer54]

I work in a Northern Powergrid Area, we were advised on our last scheme assessment to note down BS951 clamps on EICRs and to contact NPG of situation to rectify, got a letter in the post to the office saying NPG no longer fit BS951 clamps and do not replace BS951 clamps if there is a sound electrical connection.

The letter seemed to imply they did fit them once upon a time.

They did and still known to fit BS951 clamps!! Whether or not that's been or is official policy, i don't know. Actually seen them fit one to my sister incoming cable, when they came to fit an up-rated service fuse and meter!! So it's sure been the case and has been documented here in various threads too!! Personally i wouldn't dream of fitting a 951 clamp to an old PILC cable, but i'd have no hesitation fitting a constant spring earth clamp!!


As for the NICEIC, well wonders never cease!! I wonder how they intend to enforce any of these wild statements they come out with, on what's now becoming a regular basis!! lol!!

 

[Deleted member 9648]

They did and still known to fit BS951 clamps!! Whether or not that's been or is official policy, i don't know. Actually seen them fit one to my sister incoming cable, when they came to fit an up-rated service fuse and meter!! So it's sure been the case and has been documented here in various threads too!!...There are many TNS lead connections in my region and I've only come across a few 951's,and of those it was obvious they were not fitted by the DNO Personally i wouldn't dream of fitting a 951 clamp to an old PILC cable, but i'd have no hesitation fitting a constant spring earth clamp!!


As for the NICEIC, well wonders never cease!! I wonder how they intend to enforce any of these wild statements they come out with, on what's now becoming a regular basis!! lol!!Like most of the others on here you have missed the point. You state above you would not dream of a 951 clamp on a lead sheath and yet jump on the NIC for advising their members to code them when they find it on an EICR....bit of a contradiction there I'd say.

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[imago]

FFS!!.....do you really think the DNO would fit a 951 clamp???.....it would have been fitted by a sparks and not the DNO.

I neither know nor care. The NIC are yet again making waves for no good reason as it's a very simple matter. If the earth reading is acceptable then there is no need to code it at all, at the absolute most a brief mention in the notes. If it is outside of tolereance then the DNO should be notified and action taken based on what if anything they would like you to do with their equipment.

 

[Deleted member 9648]

I neither know nor care. The NIC are yet again making waves for no good reason as it's a very simple matter. If the earth reading is acceptable then there is no need to code it at all, at the absolute most a brief mention in the notes. If it is outside of tolereance then the DNO should be notified and action taken based on what if anything they would like you to do with their equipment.

So are you of the opinion that a 16mm earth wire stripped back and bound to the lead sheath with string would not be coded as long as the Ze reading was acceptable?

All the NIC are stating is that a 951 clamp is not suitable for a connection to a lead sheath and should be coded.....

 

[Ducksy]

Hey guy what's the name of the clamp the dno use has it got a name like the BS951 ???

 

[imago]

So are you of the opinion that a 16mm earth wire stripped back and bound to the lead sheath with string would not be coded as long as the Ze reading was acceptable?

All the NIC are stating is that a 951 clamp is not suitable for a connection to a lead sheath and should be coded.....

No, because it would be insecure obviously, however a 951 may or may not be. It's another situation where some donkey in an office tries to override professional experience and judgement with a catch-all 'rule'. Fortunately I am not with the NIC so I am still allowed to make judgements (based on my knowledge and experience) and will continue to do so. p

Spotting a 951 clamped to a sheath does not automatically mean that the sky is falling. I, as I'm sure have many others, have seen and tested many installations where a 951 is in place and satisfactory so no action has been taken. We've all seen ones where action is required. As the professional on site that is your call and should remain so.

 

[SJD]

Hey guy what's the name of the clamp the dno use has it got a name like the BS951 ???

Hepworth Consumer Earth Bond, e.g. http://www.sicame.co.uk/Section8/8.05-8.06.pdf ?

 

[Engineer54]

Originally Posted by Engineer54
They did and still known to fit BS951 clamps!! Whether or not that's been or is official policy, i don't know. Actually seen them fit one to my sister incoming cable, when they came to fit an up-rated service fuse and meter!! So it's sure been the case and has been documented here in various threads too!!...There are many TNS lead connections in my region and I've only come across a few 951's,and of those it was obvious they were not fitted by the DNO Personally i wouldn't dream of fitting a 951 clamp to an old PILC cable, but i'd have no hesitation fitting a constant spring earth clamp!!


As for the NICEIC, well wonders never cease!! I wonder how they intend to enforce any of these wild statements they come out with, on what's now becoming a regular basis!! lol!!Like most of the others on here you have missed the point. You state above you would not dream of a 951 clamp on a lead sheath and yet jump on the NIC for advising their members to code them when they find it on an EICR....bit of a contradiction there I'd say.

The point i was making in the first paragraph is that the DNO's ''ARE'' known to have fitted these 951 earth clamps to their PILC service cables!! Now whether that is official policy or not, is another matter. When they came out to my sister house i questioned the use, and was told the company supply them, so we use them!!! I don't know if they were supplied for this purpose or not.... I'll assume not, but they were being used as such!!

he told me that the NICEIC are now saying any TN-S with no soldered connection (earth clamp on metal sheath etc) should be made into a TT

the NICEIC are soon going to insist on this.
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I don't think i've missed the point at all....

Sorry but i don't think statements like this are useful to anyone apart from being wrong, they are stepping outside of their remit!! 1) There are perfectly safe earth clamps that can be applied to PILC cables in the way of Constant force spring clamps and Hepworth clamps!! (FACT). 2) Who are the NICEIC to determine whether you should ditch a perfectly sound earth, for an inferior one?? ...Different if they advise to contact the supply company!!

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[Knobhead]

It’s going take a lot of pressure to damage a PILC with a BS951 clamp. With regard to clamps becoming loose over time, the same problem would occur on water pipes especially hot water.

Hepworth clamps need an application tool for correct tension. Constant force springs applied correctly with a bed of copper braid around the lead provide an excellent and flexible connection.

At the end of all this, it is not you’re responsibility! Nor is it the responsibility of the NIC to give out advice on DNO matters. You’re only recourse is to contact the DNO.

 

[Deleted member 9648]

It’s going take a lot of pressure to damage a PILC with a BS951 clamp. With regard to clamps becoming loose over time, the same problem would occur on water pipes especially hot water.

Hepworth clamps need an application tool for correct tension. Constant force springs applied correctly with a bed of copper braid around the lead provide an excellent and flexible connection.

At the end of all this, it is not you’re responsibility! Nor is it the responsibility of the NIC to give out advice on DNO matters. You’re only recourse is to contact the DNO.

My point all along has been the NIC are NOT giving advice on DNO matters.....despite E54's comments I dont believe the vast majority of 951 clamps were fitted by the DNO,but by electricians without the DNO's consent. It is therefore perfectly reasonable to take the view that such a clamp is not fit for the purpose and should be coded.
Out of interest how many electricians on this forum would apply a 951 clamp to an SWA sheath to earth it?....not many I'll wager.....whats the difference?

 

[telectrix]

strip a bit of 6mm single. wrap around lead sheath then get a plumber to solder on with blowtorch. stand well back.

 

[Knobhead]

I’ve worked with PILC cables for years. I wasn’t impressed with constant force springs when I first tried them, I’ve changed my mind about them since. If the cable is live they are the only thing I’d use. On a dead cable I’d sweat a braid on to the sheath.
I would never put a BS951 on to a PILC but if it was there I’d leave it alone.

Still don’t like the springs when they bite, they are vicious.

 

[Knobhead]

strip a bit of 6mm single. wrap around lead sheath then get a plumber to solder on with blowtorch. stand well back.

A plumber would make a mess of it. I didn't want to mention wiping but if you can do a "plastic" wipe quickly then it can't be bettered. But use 16mm contra whipped around the sheath.

PS I do know the difference between whipping and wiping