Earth clamp for main earth

[Delboybully]

I have seen a standard bonding clamps being used to connect the earth to the sheath on TNS systems several times. I was led to believe this isnt acceptable and should be changed. So when i have seen these being used i have always recommended to customers that they contact their supplier to arrange it to be changed.

Today i had the DNO out to sort a LN reverse problem. This was a TNS system and had a bonding clamp connecting the earth to the sheath. I said to the guys that it needs to be changed. They said that it was perfectly ok and was a better connection than the new clamps they put on today. Is this the general opinion of the DNO or just these guys. I phoned my scheme provider and they said that the clamps are not designed for the sheath of a TNS and as such are not acceptable. But if i recommend to customers that they get the DNO out to change it and they dont, then i look like a mug and then bingo, off into the sunset goes any potential recommended work.

So should i mention that it isnt technically correct and to try to get it changed but the DNO might not change it (in which case some customers wont bother contacting them) or carry on telling customers to get it change and risk looking like a mug

 

[telectrix]

or fit the correct one yourself. should be DNO , as it's their equipment, but they may charge.

 

[Top Cat]

or fit the correct one yourself. should be DNO , as it's their equipment, but they may charge.

Did not know you could get the correct ones, do you know the part number?

 

[telectrix]

a constant pressure spring clamp, i think, and there's another, forget the name of it. tony, IQ, malcolm, and as few others can tell.

 

[Delboybully]

I didnt think we were permitted to fit them. The one they put in my home is a hepworth (fitted last year), the connection is covered in black tape so I will undo this at some point to have a look. Is a special tool needed to connect them.

 

[Knobhead]

Hepworth clamp or a constant pressure spring with a braid.

Hepworths come as a single pack, constant pressure kits are enough to do two cables.

http://www.sicame.co.uk/Section8/8.05-8.06.pdf

Constant Force Springs : 3M UK & Ireland

 

[mechelec]

hepbonds are the clamps used by the DNO in my area and you do need a special tool to fit them correctly. Some areas use a constant force spring and do not need a special tool to fit them.

constant force spring Constant Force Springs : 3M UK & Ireland

as previously mentioned the supply cable is DNO property and you shouldnt be interfering with it but if you must then using the correct equipment may help to stop you damaging their cable.

 

[Top Cat]

So no different to what's in an underground joint then.

If anyone has tried them, do you get a good reading? Saying that it could be a poor reading with soldered joint!

 

[Delboybully]

Ok more mixed messages (should i have expected anything else :smiley2.

So assuming I am not going to change the earth clamp (which i dont think i am going to do), does anyone have an answer to my question, namely should i mention that it isnt technically correct and to try to get it changed but the DNO might not change it (in which case some customers wont bother contacting them) or carry on telling customers to get it change and risk looking like a mug

 

[Top Cat]

Find a DNO guy that does it on the side?

 

[mechelec]

OK if a standard E14 clamp has been fitted then It was probably originally a TT earth system and the DNO has no responsibility to fit a correct one. They may provide a PME terminal for a charge or even fit a hepbond, it depends who you get on the day. If a DNO fitted clamp or bond is a cause for concern then they have a duty to maintain that and will do.

 

[sedgy34]

the supplier come out quite quickly if they have a bad earth

 

[Knobhead]

What reading are you getting?

If there OK. Leave it alone

 

[Delboybully]

The ones i have seen so far have been giving good readings. The problem is my scheme provider (Elecsa) say that i have to mention to the customer that these clamps are not the correct clamps to provide the earth. So should i mention that it isnt technically correct and to try to get it changed but the DNO might not change it (in which case some customers wont bother contacting them) or carry on telling customers to get it change and risk looking like a mug when the DNO come out and say its ok and dont change it?

 

[Knobhead]

Mention it and note it, but don’t go in to Adolf mode with “it must be changed”.

As I said if your readings are good, why disturb it.

 

[Silly Sausage]

Constant Force Springs : 3M UK & Ireland

T, what would you say is the best way to connect the Earthing Conductor to those springs?

 

[Engineer54]

T, what would you say is the best way to connect the Earthing Conductor to those springs?

These constant force springs are mainly suited to flexible braiding. Roll the constant force spring at least once fully around the cable sheath, then lay the braiding on. Roll the spring again at least once over the braiding and bend the braiding back against the spring and continue rolling the spring clamp around the cable until the spring is finished... You normally clamp the braiding within the spring clamp at least twice...

Depending on how long the spring clamp is, and the diameter of the cable you can adjust the amount of coils between connection to the braiding, which is why i said, at least one full wrap around the cable between laying the braiding within the spring clamp turns....

 

[Silly Sausage]

Thanks for that E.
Would you leave it as is or tape it up?

 

[Engineer54]

Thanks for that E.
Would you leave it as is or tape it up?

I would tend to use amalgamating tape over the completed termination for both protection and giving it a finished neat look!!

 

[Knobhead]

Will slightly disagree with you E54. First abrade the sheath with wire wool, it only needs a small area the size of the section of braid that will be in contact. Lay the first section of braid against the abraded sheath, then the first lap of the spring laid over it. Double the braid back over the first and lap the second turn of the spring around. Keep winding the spring around the cable until all used. Just running your fingers in the direction of the spring will tighten it up. Finally use self-amalgamating tape to cover and protect the connection.

One word of warning the springs are bloody vicious, they bite!

 

[Des 56]

Mention it and note it, butdon’t go in to Adolf mode with “it must be changed”.

As I said if your readings are good, why disturb it.

That comment made me smile lol

Mind you in reality Adolph may have said Zis must be changed

 

[Engineer54]

Agree with abrading first, ...my bad ...lolI have always rolled the spring round first, getting that nice and tight first then laying the braid down!! To be honest, so long as the spring is kept tight and the braid is firmly held in contact with the spring and sheath, ...either method will suffice in giving you a very decent earth connection to the lead sheath or even SWA come to that!! lol!!

 

[Knobhead]

I prefer the copper to be in direct contact with the lead.
The first time I used the bloody springs was on a breach joint, PVCSWA to PILCSWA. Five of the damn things to bond the joint. Two for the lead and three for the armouring. My fingers were cut to ribbons by the time I’d finished!

 

[Knobhead]

That comment made me smile lol

Mind you in reality Adolph may have said Zis must be changed

I had to check I'd spelt Adolf right!

 

[telectrix]

from the above, i take it that a self tapper and a crimp lug are not good!!!

 

[WPD Lad]

from the above, i take it that a self tapper and a crimp lug are not good!!!

Good if you want a belt lol

 

[KINKY]

T, what would you say is the best way to connect the Earthing Conductor to those springs?

Terminate the end of the braid into an earth block and then conect your earthing conductor to this.

 

[mechelec]

Another stage of the job we always carry Tony and E54 is after abrading lead sheath to apply two wraps of this mesh around the lead before winding one turn of the constant force spring followed by braid etc. It helps to give a better conductive surface to the cable especially when it is not perfectly round

Bare / Tinned Copper Wire Mesh

 

[Knobhead]

I’d forgotten about that stuff even though I’ve used it. Memories going ga-ga.