Main earthing conductor

[gazdkw82]

I took a glance at my CU the other day and noticed the main earthing conductor was terminated into a terminal block and then terminated to the supply earth. This seemed odd to me and also it didn't look very good. Why not terminate it straight to the supply earth? Should I contact my supplier?

 

[rustynails]

TN-S earthing from the sheath of the incoming cable looks very short. You shouldn't.... attach a BS951 clamp to the incoming cable as the cable is the property of the distributor. The looks like a 60amp chocolate box. Depending on the fabric of the wall there you could plug and screw an earth block to the wall then connect into that.

 

[Andy78]

Well it's not right clever is it ? a fixed MET would be the usual method of connecting to the earthing conductor. If you are asking if you can fiddle with the sheath clamp and fix directly to that, that would be a no.

 

[gazdkw82]

isn't that an henley block? or was you referring to the plastic terminal block as a choc box?

 

[gazdkw82]

Well it's not right clever is it ? a fixed MET would be the usual method of connecting to the earthing conductor. If you are asking if you can fiddle with the sheath clamp and fix directly to that, that would be a no.

no im not asking If I can fiddle with it. I was pretty sureit is the responsibility of my supplier, I’m asking if it needs reporting atall. I don’t understand why its cut and then connected to a terminal block andthen another suspect looking green cable goes from other end of that terminalblock onto the earth sheathing. Is that common practice? Isn’t it just interruptingwhat could be a continuous connection between MET and supply earth

 

[Octopus]

no im not asking If I can fiddle with it. I was pretty sureit is the responsibility of my supplier, I’m asking if it needs reporting atall. I don’t understand why its cut and then connected to a terminal block andthen another suspect looking green cable goes from other end of that terminalblock onto the earth sheathing. Is that common practice? Isn’t it just interruptingwhat could be a continuous connection between MET and supply earth

What's the Zl and Ze?

You could get your supplier to look but unless the readings are high I doubt they will be interested!

 

[Richard Burns]

I would suggest that someone at some point has looked at the earth cable on the sheath and said, oh that is too small (probably incorrectly) and then cut the cable and added this new larger green and yellow cable.
This will have no effect, since they left the last bit of cable to the sheath, except to make things more complicated at a later date, such as now.
So long as the terminal block connection is sound and, as Murdoch says, your test results are good then this will be OK ish.
Changing the terminal block to an earth block fixed in place would look better.
Effectively the current state is that the suppliers earth is now just the clamp and small section of cable. So the MET should be directly after that.

 

[gazdkw82]

I get my new MFT soon so ill do a ze reading

 

[hightower]

As others have said, stick an earth block in, something like this maybe. https://www.tlc-direct.co.uk/Products/TLEB4.html

It will essentially just be doing the same job as the current choc block, but will look a little better.

 

[gazdkw82]

If I replace that terminal block with a earth terminal,where do I fix the terminal?? Cant leave it hanging, There’s only about 2 “ onthat little green cable

 

[hightower]

If I replace that terminal block with a earth terminal,where do I fix the terminal?? Cant leave it hanging, There’s only about 2 “ onthat little green cable

Well we can only go off the photo you've posted, but to me it looks like there'll be just enough length to fix it to the wall right next to the clamp.

 

[gazdkw82]

I can try

 

[Octopus]

Well we can only go off the photo you've posted, but to me it looks like there'll be just enough length to fix it to the wall right next to the clamp.

Are you sure. The dno cable looks too short to me and hence why I suspect the choc block was used.

A closer up picky would help.

 

[hightower]

Are you sure.

I'm not, hence why I said we can only go off the photo - to me it looks like it should just be long enough, but the only person who can really say is gazdkw82.

 

[gazdkw82]

worst case scenario I can always fix a timber block to the wall next to It which should make it closer

 

[Risteard]

It's standard practice here to use an ISCO for the MET.

 

[gazdkw82]

What's an Isco?

 

[hightower]

What's an Isco?

Google is your friend:

https://www.google.co.uk/search?q=i...xePMAhXsAsAKHcWABbAQ_AUIBygB&biw=1440&bih=775

 

[gazdkw82]

Is this the same thing

5-Way SP 100A Service Connector Block 25mm² | 100A Connector Block | NoLinkingToThis

 

[Midwest]

To be honest, the whole thing looks a mess. I personally would call the DNO to have a look at their earth & your suppler to have a look at their tails. Then I would ask the property owner (think that's you), what do they want to do with their tails from the meter to the Henley blocks (i.e. get rid of Henley blocks) and how about supporting that white cable properly, or is it redundant? And quite frankly, the cupboard could do with a bit of a hoover.