Main Earthing Terminal link up

[mattcos1972]

Hi guys,
Quick Q for you this Sunday morning.
Have recently updated CU and also run in bonding to gas and water. Have 2 CU's in house now as shed is being fed from a non RCD protected (garage CU) and house is all on split RCD board.
Anyway...I am going off track....
Here's the Q. With the all the bonding and the 2 CUs the 4 way earth terminal was insufficient so I have linked up another 4 way using 16mm earth connector as I didnt have any 8 way blocks to hand. Is this acceptable to leave in place or am I required to have only one earthing block?
Here's a photo of the arrangement in case my babbling is unclear lol!!

 

[bugsy]

I'd install an eight way earth block, I would also RCD protect supplies for garage , shed etc.

 

[mattcos1972]

I'd install an eight way earth block, I would also RCD protect supplies for garage , shed etc.

Cheers Bugsy,
The shed circuits are RCD protected at CU in the shed, so I specifically didn't want them "double" RCD protected as I didn't want RCDs tripping all over the place in the even of a fault.

 

[DurhamSparky]

are the supply cables to the shed buried or clipped to any overground structures?? do they have any type of mechanical protection?? SWA/Metal conduit or even PLastic conduit if surface mounted??

why not remove the RCD isolator from Shed CU and replace with isolator 2 pole and buy an enclosure for your RCD switch and mount it just after service connector!!

Winner!!! will cost you about £10 for stuff..!

steve

 

[irishsailor]

Hi Also do you not need a Do Not Dissconnect Earth Label Next to the block

Chris

 

[DurhamSparky]

maybe he should place that label after he disconnects it and replces

 

[Des 56]

If the jointing piece is removed,connection is lost to the rest

On an installation we can use a single earth cable for gas and water as long as its unbroken because if one of the clamps is removed the bonding is maintained at the other
The same I believe would apply here,

Fixing the 2 pieces side by side and fitting a solid link,something like inside consumer unit bars may be better and look tidier

 

[chris gray]

my 2p worth.
surely if there is no rcd inline to the shed then the feed to the shed is not rcd protected?

 

[Spudnik]

The supply to the shed does not require RCD protection if the installation method allows.

 

[mattcos1972]

Evening all.
Looks like my email alerts weren't working as I didn't realise anyone had replied!! lol!

Right. first of all thought I'd let you all know my 8 way MET is going in tomorrow! the only reason the two 4s are in is because those nice chaps at screwfix didn't pack the bloomin' 8 way that I ordered, and I found out when I went to hook it all up. I was just checking to see if the set up I had er......dare I say....bodged .....was acceptable. No worries on that.
Also photo was taken before the BS951 tag was attached.....

OK cant remember who brought what up, but here's how the installation is set up......feel free to tune out about now lol!!

TN-S supply.25mm Tails from meter to DP isolator.....from Isolator to Henley block. Two sets of 25mm tails from Henley Block....one pair supplying house CU which is split RCD. One pair supplying 2 way "Garage" CU consisting of 63A Main Switch and 40A MCB feeding 6mm SWA running at high level along outside of house, down into garden and running along the fence to the shed (I would like to point at this point that I did not put this cable in!!! ) Inside the shed is a further CU with shared Main Switch / 30mA RCD and 3x MCB 2x 32A and a 6A for ring, outside socket and lighting, respectively.

No electrode at shed as no extraneous conductive parts out there so earthing for shed is taken from the cpc in the SWA and from its sheath. So in essence the house earth IS supplying the shed earth. I am aware that there are 2 schools of thought on this and from what I gather its the extraneous conductive parts that is the decider in shed earthing. Anyway that was all in place before my dirty paws got involved lol!! (remember I am just changing the CU....in theory lol)
OK so back to earthing....
After discovering I had no bonding to my gas supply and that the bonding to my water pipes was at best.....rubbish, I have installed / replaced both with 10mm copper cable running to my snazzy 2 x 4 way MET lol!! Both CUs in the house are earthed directly and independently to MET with 16mm copper cable.


Also, as you know Steve, I discovered that the lighting circuit in the house is not earthed and all my lights and a few switch fittings were class 1 and metal. These have all been changed (bathroom downlights due to be replaced this week for IP65 class 2......so I cheated and changed the CU before they were delivered! ) I am presently on the look out for labels for the CU to indicate that the lighting circuit is indeed not earthed and that no metal fixings should be used. Steve, thanks again for that pdf regarding unearthed lighting.

So.....come on then....let the dogs out! lol

 

[pennywise]

Here's the stickers you can get them at most of the wholesalers unbranded

NICEIC - approving excellence

 

[mattcos1972]

Here's the stickers you can get them at most of the wholesaler unbranded

NICEIC - approving excellence

Thanks for that mate!

 

[Davey101]

Personnaly, I wouldnt worry about two earth bars at all, evey D/board I have connected in the past couple of years has had two, and the last job I did had two main earth bars (although for slightly different reasons, as one was a 'clean' earth). If I had the choice, I'd put a single bar in, but I wouldnt lose any sleep about having two. If it were me, I would mount them side by side, with a very short 'U' shaped piece of 16mm to connect them.

 

[mattcos1972]

Personnaly, I wouldnt worry about two earth bars at all, evey D/board I have connected in the past couple of years has had two, and the last job I did had two main earth bars (although for slightly different reasons, as one was a 'clean' earth). If I had the choice, I'd put a single bar in, but I wouldnt lose any sleep about having two. If it were me, I would mount them side by side, with a very short 'U' shaped piece of 16mm to connect them.

Cheers Davey.
Sorry for the delay answering. I picked up an 8 way just to keep it neat. Here's the finished arrangement....

 

[Spudnik]

Ideally, you should disregard the clamp and fix the label under or above the MET with screws.

Alternatively, there are specific plastic labels that can be used.

 

[chris gray]

and maybe would of put a ring crimp on it - just to make it look tidyer

 

[mattcos1972]

Ideally, you should disregard the clamp and fix the label under or above the MET with screws.

Alternatively, there are specific plastic labels that can be used.

and maybe would of put a ring crimp on it - just to make it look tidyer

Cheers guys.....I'll get to it...look out for my next instalment!!

and maybe would of put a ring crimp on it - just to make it look tidyer

Hey Chris,
Its just dawned on me you were talking about the connection at the supply end weren't you? That was the existing earth cable I used as I wasn't sure if I was allowed to mess with the supply end of things but I think you are right...it makes the rest of my work look unsightly doesn't it?

Ideally, you should disregard the clamp and fix the label under or above the MET with screws.

Alternatively, there are specific plastic labels that can be used.

Jason is this the label you were referring to chap?

Google Image Result for http://www.labelsourceonline.co.uk/ProdImages/ess2.gif

 

[pevvers]

Cheers Davey.
Sorry for the delay answering. I picked up an 8 way just to keep it neat. Here's the finished arrangement....

So, has nobody got any qualms at all with the BS951 clamp on a lead sheath, which is the DNO's equipment?

Please say someone has....

 

[mattcos1972]

So, has nobody got any qualms at all with the BS951 clamp on a lead sheath, which is the DNO's equipment?

Please say someone has....

Hey Pevvers.

I take it that's a no-no. But its been there since "whenever". I changed the consumer unit and got the installation up to standard according to BS 7671 and advice from the NICEIC. Would I have to have that changed that as well? The Siemens engineer (for Brit Gas) came down to fit the DP isolator and didnt bat an eyelid when he saw the earth cable.

What would you do chap?

 

[Notsosmart]

So, has nobody got any qualms at all with the BS951 clamp on a lead sheath, which is the DNO's equipment?

Please say someone has....

Quite right Pevvers, should either be a Hepworth clamp or a TNC-S system. 951's are very much frowned upon and shouldn't be used on a sheath (lead especially) (unless a supply employee fits them)

 

[pevvers]

The Siemens engineer (for Brit Gas) came down to fit the DP isolator and didnt bat an eyelid when he saw the earth cable.

What would you do chap?

I'd ring up the DNO and ask for them to come and install a system that was up to the job of getting an earth from a lead sheathed cable. The problem with the BS951 clamps is that they can become loose against a soft metal like lead, and as they are tightened up over time they can then cause a short between the line and the earth... And I'm pretty darn sure that there will be a pretty big bang when this happens!!

No offence to the DNO operatives, but from what I've heard they don't really give a monkeys about much anyway. I would like to be proven otherwise though!

 

[mattcos1972]

Quite right Pevvers, should either be a Hepworth clamp or a TNC-S system. 951's are very much frowned upon and shouldn't be used on a sheath (lead especially) (unless a supply employee fits them)

OK chaps...Advice time...........

I am getting a Ze of 0.11 ohms and functionally everything is A- OK. That BS951 on the lead sheath has been on there for god know's how long. I Realise that clamping a BS 951 on a lead sheath can potentially crush the conductors inside if overtightened but this does not seem to have been the case. What would you do in the same situation as me?

I'd ring up the DNO and ask for them to come and install a system that was up to the job of getting an earth from a lead sheathed cable. The problem with the BS951 clamps is that they can become loose against a soft metal like lead, and as they are tightened up over time they can then cause a short between the line and the earth... And I'm pretty darn sure that there will be a pretty big bang when this happens!!

No offence to the DNO operatives, but from what I've heard they don't really give a monkeys about much anyway. I would like to be proven otherwise though!

Sorry Pevvers,
We must have been typing at the same time
Cheers mate. I will get on to the DNO and talk the NICEIC tomorrow......and of course let you know how helpful they were(n't)

 

[pevvers]

OK chaps...Advice time...........

I am getting a Ze of 0.11 ohms and functionally everything is A- OK. That BS951 on the lead sheath has been on there for god know's how long. I Realise that clamping a BS 951 on a lead sheath can potentially crush the conductors inside if overtightened but this does not seem to have been the case. What would you do in the same situation as me?

Cheers mate. I will get on to the DNO and talk the NICEIC tomorrow......and of course let you know how helpful they were(n't)

I'll put a fiver on the NICEIC being helpful, and a fiver on the DNO not being helpful. Let us know if you even manage to get through to anyone at the DNO who has the foggiest what you're even talking about!

Sorry Pevvers,
We must have been typing at the same time

No need to apologise!

 

[mattcos1972]

I'll put a fiver on the NICEIC being helpful, and a fiver on the DNO not being helpful. Let us know if you even manage to get through to anyone at the DNO who has the foggiest what you're even talking about!



No need to apologise!

lol! Cheers chap.

I make you right the NICEIC have been great all the way. The reason I want this job absolutely perfect (apart from the fact that I want all my work to be perfect ) is that the NICEIC will be inspecting it as part of my approval as a Domestic Installer.
Make you right with the DNO though! Although in fairness when I asked British Gas to come down to fit the DP Isolator they were down within a few days no fuss. When I tried to get EON to install one at my mum's house so I could work there too, it took about 6 calls before anyone had the foggiest what I was on about!!

I'll be back with more news on the morrow.

Thanks again to everyone for their input.

 

[mattcos1972]

Ideally, you should disregard the clamp and fix the label under or above the MET with screws.

Alternatively, there are specific plastic labels that can be used.

How's this?

 

[Spudnik]

Spot on

 

[mattcos1972]

Spot on

YAY!!
Cheers Jason.

Matt

 

[Graeme Harrold]

With regards to stickers, get your local signmaker to print them off. I have mine all personalised so clients have my number right where they need it......

 

[mattcos1972]

With regards to stickers, get your local signmaker to print them off. I have mine all personalised so clients have my number right where they need it......

I saw those the other day. Thats a damn good idea! Even I cant remember my number half the time!