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Thoughts on this earthing at cut out.....

Discuss Thoughts on this earthing at cut out..... in the Electrical Forum area at ElectriciansForums.net

Gavin John Hyde

Electrician's Arms
On a job this evening just taking a look around and meeting customer as wants downstairs rewired.
Only collecting keys before i go back and do a few tests and quote fully.
Appears at sometime to have been TNS but changed to PME?
Instead of earth and Neutral joining in the cut out. They are joined in a Henley.
Is this permissable?
First thought was no. But more I think about it. What difference does it make so long as they join - be it in cutout or henley a few inches later?
Thoughts?

Images show earthing in henley going behind board to CU.
Old bonding strap fixed to outer sheath!!
Cut out without earth going in the side. On closer examination it appears there is a small hole, presumably for the earthing but has lack of access.

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TJ Anderson

Forum Mentor
That looks like a non-DNO TNCS. Also that BS951 clamp should have never been used for TNS earthing conductor, crushing the cable.
 
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Gavin John Hyde

Electrician's Arms
That looks like a non DNO TNCS. Also that BS951 clamp should never be used for TNS earthing conductor, crushing the cable.
Agree on the BS951 clamp used for TNS. it certainly looks like a improvised PME set up. but is it compliant? I will test the readings later in week when I go back. might have to get WPD out to give once over.
 

TJ Anderson

Forum Mentor
Thing is you won't really know if it is. You will have a low impedance loop L-N & L-E, most likely less than 0.35 ohms Ze, but is it really TNCS? Could have a look in neighbours house if poss, see if they have a TNCS cutout. Should definitely get DNO out to look at that.
 

Wilko

Electrician's Arms
I've sent in special pics like this to local DNO a few times and they will do a free "safety check" if they feel it's warranted.
 
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lemonkettaz

Regular EF Member
If it’s TNS will be different readings L-E and L-N being separate conductors whereras TNCS would give exact same readings as it’s the same conductor ?
 

TJ Anderson

Forum Mentor
If it’s TNS will be different readings L-E and L-N being separate conductors whereras TNCS would give exact same readings as it’s the same conductor ?
Yeah, you get same readings as they are supplied by same conductor. The issue is, this is using the dedicated neutral of the old TNS as a PEN conductor when it may not actually be one...
 

DefyG

Regular EF Member
Got the DNO out on a job last year with too high Ze reading for a TNS and the remedy? - They did exactly as shown by Gavin's pics!
So not necessarily a DIY PME!
 
Is it a secondary cutout? That's where I've generally seen this done, especially when they are a few neutrals to combine, so the cutout is effectively extended using a block. But even then, I've not seen an earth thrown in there ad-hoc.

Anyway, there's only one neutral so I'm probably wrong.
 

Gavin John Hyde

Electrician's Arms
Is it a secondary cutout? That's where I've generally seen this done, especially when they are a few neutrals to combine, so the cutout is effectively extended using a block. But even then, I've not seen an earth thrown in there ad-hoc.

Anyway, there's only one neutral so I'm probably wrong.
No secondary cutout. It comes in from outside. To immediate left is the front door.
 

Vortigern

Regular EF Member
Of course in the regs the use of neutral and earth combined is not permitted within the installation. But technically I guess it is not within the installation it is prior to the meter and within the responsibility of the DNO. I do know of electricians that do not hesitate to do their own PME like this so yes it may be a diy. Update us @Gavin John Hyde when they look.
 

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