Extending a met earthing block

[jim2490]

Have run out of connection points for earth termination at the MET. Currently using an 8 way block with mainly 10mm cables going in and one final 16mm earth cable out to the (old MEB) incoming earthing point.
Can I double up on this block with a second 8 way block and loop a 10mm earthing cable or 16mm to join the two to make a 16 way earth termination point.
Have searched for domestic earthing blocks, but they only seem to go up to 8 connections.
Advice appreciated.

 

[JohnW2]

Have run out of connection points for earth termination at the MET. Currently using an 8 way block with mainly 10mm cables going in and one final 16mm earth cable out to the (old MEB) incoming earthing point. Can I double up on this block with a second 8 way block and loop a 10mm earthing cable or 16mm to join the two to make a 16 way earth termination point. Have searched for domestic earthing blocks, but they only seem to go up to 8 connections.

I have precisely the same situation and have done exactly as you describe. I actually use the end of the 'incoming' 16mm² earthing conductor as the means of joining the two 8-way blocks, so both blocks have direct screw connections to the main earthing electrode, as well as being 'joined together' by it. So long as it is difficult/impossible to find bigger blocks than 8-way, I see no alternatives, and nor can I see any real problem with what I've done. That does not, of course, guarantee that everyone will agree with me!

Kind Regards, John

 

[bernardgreen]

I agree with John's method.

 

[ban-all-sheds]

Have run out of connection points for earth termination at the MET.

How?

Currently using an 8 way block with mainly 10mm cables going in and one final 16mm earth cable out to the (old MEB) incoming earthing point.

So that's 1 way used to connect to the supply earth.
1 way for the CU.
Let's assume you have 2 CUs.

That leaves you 5 ways for bonding incoming services.

How many do you have?


Set this downloading while you have lunch (it's 160MB)

http://www.entrelecsales.com/pdf/abbcatalogs/LV042.pdf

and look at pp 402-407

 

[JohnW2]

Have run out of connection points for earth termination at the MET.

How?

I know the question wasn't directed at me but, in my very similar situation, the answer is very simple - lots of sub-mains/CUs, plus bonding.

In fact, in my situation it's worse than that. I inherited a situation in which all the submains were run in 16mm² singles with a 6mm² CPC. That being unsatisfactory, I upgraded all the CPCs to 10mm² but, rather than rip out the 6mm² ones, left them in place, in parallel with the new ones (hence 16mm² total effective CSA) - it seemed daft not to.

Set this downloading while you have lunch (it's 160MB)
http://www.entrelecsales.com/pdf/abbcatalogs/LV042.pdf
and look at pp 402-407

I'm not very patient - do I take it that this revelas earth blocks with more than 8 ways? Whatever, I see absolutely nothing wrong with the arrangement I have, which is functionally identical to the situation which would exist with a 15-way block.

Kind Regards, John

 

[ban-all-sheds]

I'm not very patient

Do you never leave your PC?

do I take it that this revelas earth blocks with more than 8 ways?

Not exactly, but it does reveal solutions which are more elegant than yours.

Other makes are available, e.g. http://www.erico.com/products.asp?folderID=192

 

[JohnW2]

do I take it that this revelas earth blocks with more than 8 ways?

Not exactly, but it does reveal solutions which are more elegant than yours.

OK, I'll have a look later. However, I'm not sure that I'm necessarily too concerned about 'elegance' - can you actually see anything wrong with my method?

Kind Regards, John

 

[ban-all-sheds]

No.

 

[JohnD]

Another (more common) way is to use the earth strip in the consumer unit. Modern CUs have very long strips with plenty of holes.

 

[JohnW2]

Another (more common) way is to use the earth strip in the consumer unit. Modern CUs have very long strips with plenty of holes.

Yes, increasingly common in standard/'simple' domestic installations, but not really applicable in a situation like mine (as described above). In any event, most of the 'holes' in a CU earth strip (other than those intended for incoming earthing conductor and bonding) would usually not take 16mm² conductors, and I'm not even sure about 10mm², not to mention the congestion within the CU which would result - and nor would there be many 'spare holes' if the CU were fully populated with MCBs/RCBOs.

Kind Regards, John

 

[JohnD]

As far as I can remember, ours goes to the first DB, in this lobby, and the others around the premises are submains.

View media item 1575 View media item 1574
plenty of big holes in these ones
View media item 1092 View media item 6822 View media item 12149

 

[bernardgreen]

I would be reluctant to use the "earth" bar in a CU as a link in the main bond ( 10 mm ) as, after the holes for wires and screws have been drilled, the bar seems have less than 10 square mm of metal.

 

[JohnW2]

plenty of big holes in these ones ...

It's difficult to see from your pictures how big the holes are, but I'm not so sure about 'plenty'. In the Memera 2000AD (the clearest piccie), there appear to be 22 holes, and spaces for 17 circuits. So, by the time each circuit has its 'hole' and one has an incoming earth, there'd only be four left for anything else one wants to do ... and I also tend to agree with Bernard's point - the amount of metal left in one of those earth bars (after all the holes have been drilled) is tiny compared with a proper earth block.

Kind Regards, John

 

[333rocky333]

Is there any reason a so called 8 way block cant be used for up to 16 entries, after all a dist board earth bar usually only has 1 screw per conductor

 

[Scoby_Beasley]

Set this downloading while you have lunch (it's 160MB)

http://www.entrelecsales.com/pdf/abbcatalogs/LV042.pdf

and look at pp 402-407

Eh? I tend to go for longer than a 7 minute lunch break these days