Thoughts on this consumer unit change

[MickSmith5824]

Hi all

Been asked to quote on this consumer unit change (see photo). Wondering what people's thoughts are on the earthing situation. As can see it is tns but earthing doesn't look to clever to me. It's stranded ali by looks of it. Not sure of CSA of it, looks like could potentially be 10mm at a push. The tails are 16mm and not sure on main fuse size. Could this potentially be compliant? It's likely I may need to relocate new consumer unit as limited for space so in an ideal world would take the main earth into wall mounted block and then from here to consumer unit and to water and gas. As can see from photo the gas is bonded straight from service cable also at the moment.

Any clarification on this would be appreciated.

 

[MickSmith5824]

Well spotted. Is it feeding something else, off another phase?
...and how is it earthed?
Straight from fuse(s).... not isolated?

Photo is not that clear but if go ahead with job will obviously sort any isolating/fusing issues out. Looks like coming out of our single phase and is interlinked somehow with our meter and what ever that device is on left? Any clue what this is?

 

[Julie.]

If the incomer is the bottom one, with the earth attached, then that's pretty normal for old earthing by the dno.

They are obliged to provide and maintain the earth only if it was there previously, as it is, there is an earth; so they comply with their obligations.

I would fit the new cu as normal but add a MET with 16mm^2 between the cu and MET, and a 10mm^2 between the MET and the existing bond where it connects to the cable incomer, and connect the twin 7/44 to the MET.

That way your (customer's) side is in every way compliant, you could also contact the dno and say you don't believe their existing earthing is being maintained properly as it is high resistance, they may follow up and fit a newer earth connection between your MET and their cable.

You could use the poor arrangements associated with the shared/interlinked supply to get them there.

 

[MickSmith5824]

If the incomer is the bottom one, with the earth attached, then that's pretty normal for old earthing by the dno.

They are obliged to provide and maintain the earth only if it was there previously, as it is, there is an earth; so they comply with their obligations.

I would fit the new cu as normal but add a MET with 16mm^2 between the cu and MET, and a 10mm^2 between the MET and the existing bond where it connects to the cable incomer, and connect the twin 7/44 to the MET.

That way your (customer's) side is in every way compliant, you could also contact the dno and say you don't believe their existing earthing is being maintained properly as it is high resistance, they may follow up and fit a newer earth connection between your MET and their cable.

You could use the poor arrangements associated with the shared/interlinked supply to get them there.

Thanks Julie

 

[ipf]

Watch that earth bond when you take it off....for damage to the lead sheathing. If so, that could be used to get DNO involved, also.

 

[Vortigern]

I guess this is a flat and the MICC is the upstairs supply. Under ESQCR reg 24 the DNO must maintain an adequate earth. Having said that, an adequate earth to us and them are two different things. I maybe would get my micrometer out and measure their earth but again guess is they are equivalent to 5mm² an adiabatic could settle the adequacy of them. Ideally I would want to see an earth marshalling point and get rid if that BS951 clamp and have it in the MET/marshalling point. I am sure you wont have to bring out the big guns unless you get a jobsworth in the office, but if so elevate to the supervisor and tell them what you need.

 

[Mike Johnson]

@Vortigern Your change in Avatar has me intrigued, are you up a Youngman tower or did they eventually cage you. ?

 

[MickSmith5824]

I guess this is a flat and the MICC is the upstairs supply. Under ESQCR reg 24 the DNO must maintain an adequate earth. Having said that, an adequate earth to us and them are two different things. I maybe would get my micrometer out and measure their earth but again guess is they are equivalent to 5mm² an adiabatic could settle the adequacy of them. Ideally I would want to see an earth marshalling point and get rid if that BS951 clamp and have it in the MET/marshalling point. I am sure you wont have to bring out the big guns unless you get a jobsworth in the office, but if so elevate to the supervisor and

Well spotted Vertigen. Your correct there is actually a property above. So does it look like they have taken neutral from our first head and took a phase from head 3. I'm intrigued by what that box is next to our meter? And the link that looks to be between it

 

[ipf]

No seals on two of the phase carriers, I see and it's not long since the other one was done, so did the 'engineer' know about the other neutral.

 

[MickSmith5824]

No seals on two of the phase carriers, I see.

Ok thanks IPF. What's the black cable coming out the meter?

 

[ipf]

Ok thanks IPF. What's the black cable coming out the meter?

Can't really tell, mate....it's a bit unclear and not being on site, it'd be speculation.

 

[snowhead]

The black cable goes to the Comms unit at the side, looks like the one below as used by B.G

 

[MickSmith5824]

The black cable goes to the Comms unit at the side, looks like the one below as used by B.G


View attachment 65115

Top man Snowhead I believe it indeed is

 

[UNG]

Watch that earth bond when you take it off....for damage to the lead sheathing. If so, that could be used to get DNO involved, also.

I would get the DNO to take it off when they are sorting the other earth clamp out it is not worth the risk at any level of something going wrong