TN-S Earth clamp

Had a proper look at the earthing on the new place today. The supply earth is provided by a clamp onto the sheath. It's not, so far as I can, a tightenable clamp.
https://www.flickr.com/photos/38355182@N08/49930792168/in/dateposted-public/
It has a 10mm cable in which looks like it only just fits, can't see how I'd get a 16 in there. (tails are - at the moment - 25mm as far as a Henley, then down to 16mm)
I noticed that the clamp rotates freely around the sheath. Is that to be expected? I will get round to measuring the earth soon when the replacement test lead turns up.
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snipped-for-privacy@blaukopf.com wrote:

Crimp a ring terminal on the cable? Depends what size ratchet crimp you've got/can borrow?
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On Sunday, 24 May 2020 21:03:22 UTC+1, Andy Burns wrote:

Thanks!. Why didn't I think of that.
My crimper stops at 10mm, but I'm sure I can find someone with a 16.
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On 24/05/2020 20:49, snipped-for-privacy@blaukopf.com wrote:

FWLIW I think I'd ask if a "proper" PME can be supplied
https://www.ukpowernetworks.co.uk/electricity/earthing
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Robin
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On Sunday, 24 May 2020 21:44:45 UTC+1, Robin wrote:

I was considering that. Assuming the clamp isn't expected to move as it does (??) I was going to call up and express concern about it, and see if that ended up with a PME conversion.
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On 24/05/2020 22:31, snipped-for-privacy@blaukopf.com wrote:

I was leaving the clamp to my youngers and betters :) But FWIW (a) a clamp that moves patently means your Ze can change randomly, (b) clamps (even constant force clamps) on lead sheathing are now a no-no, and (c) I think tightening a clamp is for the brave and courageous.
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On 24/05/2020 20:49, snipped-for-privacy@blaukopf.com wrote:

No, the clamp should not move and will be an ineffective earth connection.
Report it to your DNO and they should either rectify it or provide PME. (this may be delayed due to Coronovirus Regs)
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On Monday, 25 May 2020 09:44:10 UTC+1, Jack Harry Teesdale wrote:

rth is provided by a clamp onto the sheath. It's not, so far as I can, a ti ghtenable clamp.

blic/

how I'd get a 16 in there. (tails are - at the moment - 25mm as far as a He nley, then down to 16mm)

e expected? I will get round to measuring the earth soon when the replaceme nt test lead turns up.

.
Thanks. That's what I thought, but nice to have it confirmed.
I rang up UK power and they were somewhat unhelpful, and want to know what Ze is before they will do anything (I tried arguing that what it is NOW is irrelevant, and I don't want to start waggling their clamp to demonstrate t hat it will change). Well, gives me something to do. I will call back and hope I get someone more helpful.
There's a lead water main. Turns out it does have its uses....
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On Mon, 25 May 2020 01:59:14 -0700 (PDT), snipped-for-privacy@airsource.co.uk wrote:

You would always give them an 'estimated' figure :-)
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On 25/05/2020 10:21, Scott wrote:

Especially after slackening the earth clamp off.
Couple of ohms should do it.
I like your thinking.
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Adam

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On Monday, 25 May 2020 09:59:17 UTC+1, snipped-for-privacy@airsource.co.uk wrote:

earth is provided by a clamp onto the sheath. It's not, so far as I can, a tightenable clamp.

public/

e how I'd get a 16 in there. (tails are - at the moment - 25mm as far as a Henley, then down to 16mm)

be expected? I will get round to measuring the earth soon when the replace ment test lead turns up.

on.

t Ze is before they will do anything (I tried arguing that what it is NOW i s irrelevant, and I don't want to start waggling their clamp to demonstrate that it will change). Well, gives me something to do. I will call back an d hope I get someone more helpful.

If you're 100% RCDed it's not ideal, but not an immediate threat to life. I f you're not RCDed it is.
Be aware that they will only reconnect your supply after the work if your w ater & gas/oil are bonded.
NT
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On 25/05/2020 11:48, snipped-for-privacy@gmail.com wrote:

and IIRC to current (continuous 10mm) standard
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On Monday, 25 May 2020 13:13:32 UTC+1, Robin wrote:

Sorting out the bonding mess was how I noticed the problem in the first place!
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On 25/05/2020 13:42, snipped-for-privacy@airsource.co.uk wrote:

Assuming that the electric co are not complete dickheads then they will probably install an isolator and earth block but not actually connect back up your power or the earth.
It's a 15 minute DIY job that does not require an electrician just a flat screwdriver, allen keys and snips (or Stanley knife if you prefer) to connect into these [1]
If you do need to cut any meter seals I have loads of NE ones available.
I doubt they will PME it. I suspect they will jut fit a series 6 cutout and keep it as a TN-S.
https://www.wt-henley.com/pdf/14688_series_6_house_service_cut_outs_2.pdf
[1] Not allowing for the 30 minutes to find the Allen keys that you put somewhere safe the last time you used them:-)
--
Adam

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What does 'continuous' mean in this context? Surely it doesn't mean no joints? Or does it means no thinner sections?
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Roger Hayter

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It means if your water bond is on the way to the gas, so you do it all in one length, make sure it is one length(not cut). That way if someone disconnects the water bond, gas is still bonded.
I think I learned that here, but I've seen it referenced elsewhere too.
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But a terminal block fixed to the wall with separate wires to gas and water would be ok? Depends on the precise layout which is ieasier.
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On 26/05/2020 13:32, Roger Hayter wrote:

Call it an earth marshalled busbar terminal and all is fine.
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Adam

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On 26/05/2020 12:59, snipped-for-privacy@airsource.co.uk wrote:

Yes - sorry I was misleadingly vague.
AIUI it's not mandatory part of BS7671 but something that BS7430 and Guidance Note 8 says "should" be done - and makes for a quieter life.
And while there's no regulation against joints in main bonding with junction boxes (or chock strip) suitably labelled I'd extend with an uninsulated crimp.
PS
Sorry too that for some reason I thought I knew UKPN was your DNO.
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You mean if you fix a 2" X 3/4' chunk of brass on the wall with several green and yellow wires going into it you would have to label it "safety electral earth etc"? And should you enclose it to discourage interference?
Yes it makes sense, though my electrican did not bother. Maybe he (or I) might have done if it hadn't been in a workshop.
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Roger Hayter

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