Advice please. CU change and incoming supply

[Johnlondon]

Hi all,

I'm in the progress of becoming part p qualified and have my first job ofchanging a CU. I'm doing it it in approx 6 weeks so doing my research to ensureI'm doing it all properly. I'm 37 and have been working in property maintenancefor 10 years and have passed my 2330 so I'm not a complete novice.

Simple (hopefully) question for you all. As you can see from the photo, itappears to be an old paper insulated lead covered cable. As you can also see,the earth connection to the cable is very dodgy and needs replacing. It's a TNSsystem and the next door (correct me if I'm wrong) feed is looped in from theproperty I'm dealing with. Even if it wasn't changed, any testing andmeasurements would be affected by the next door property as the earth isconnected to their cable also. Just to confirm, I DO NOT touch this and insteadarrange for the supply co to come out and rectify? Presumably they may also fita new fuse unit. I know the normal thing for you guys to pull the mainfuse(lets say the tags are cut) and whilst I'm confident to do this and have1000v gloves, I'd prefer not to deal with result of a possibly brokencarrier(where do I get a replacement??) and instead would like the DNO to fita main isolator after the meter. Am I right in thinking this will all dependwho the customer's supplier is as to what they will do and what they willcharge?

Many thanks

 

[Des 56]

Even if it wasn't changed, any testing andmeasurements would be affected by the next door property as the earth isconnected to their cable also.

I can't see the detail of the incomer (image too small and eyes too knackered)but would assume that the looped supply would also have a strap or wire also looping the supply earthing so next door won't be affected


I DO NOT touch this and instead arrange for the supply co to come out and rectify

Rectify what exactly,from my perspective,all looks well



Presumably they may also fita new fuse unit. I know the normal thing for you guys to pull the mainfuse(lets say the tags are cut) and whilst I'm confident to do this and have1000v gloves, I'd prefer not to deal with result of a possibly brokencarrier(where do I get a replacement??) and instead would like the DNO to fita main isolator after the meter.

That's a fair enough comment,but this is exactly the scenario where sparks of old would on the whole not even consider involving the supplier for a moment,we would simply drop the lives out from the tails connection block and leave the new tails long enough to go to the meter and book the supplier up to connect the new tails,or maybe connect them ourselves if those seals are not intact

 

[Engineer54]

What ever is happeneing next door as far as the DNO installation is concerned, is really none of your concern unless your Ze does not comply with the minimum value of a TN-S supply.


Why not install the isolator and co-ordinate connection by the DNO as and when your ready. I can't really see what's happening with the main earth connecting off the cables. You could rectify your self with constant force earth springs!! Or as you state, have the DNO sort it out while connecting up the new isolator. Unfortuately, you will in all likelihood be charged for an isolator supplied and fitted by the DNO....

 

[Engineer54]

That's a fair enough comment,but this is exactly the scenario where sparks of old would on the whole not even consider involving the supplier for a moment,we would simply drop the lives out from the tails connection block and leave the new tails long enough to go to the meter and book the supplier up to connect the new tails,or maybe connect them ourselves if those seals are not intact
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Haha, i was trying not to mention pulling the fuse yourself!! It would certainly make things a lot easier not involving the supplier!!​

 

[telectrix]

as E54 says. just dump the choc block and make a good connection with new earthing conductor to the soldered on tail from the cable sheath

 

[ste77]

im suprised they didnt fit the water stop cock in the cupboard too, then they could have all the building services isolation points in the one place lol

 

[telectrix]

im suprised they didnt fit the water stop cock in the cupboard too, then they could have all the building services isolation points in the one place lol

nah, that will be t'other end of the house, in the kitchen, buried behind units.

 

[Johnlondon]

Ok, so what you're saying is I don't really need to involve the DNO? I assumed the earth connection to the sheath via choc block would need replacement? Also, if I pull the main fuse do I HAVE to fit a main isolator?

Just to remember, this will be my assessment job where the NICEIC will visit and inspect. I want to make sure all is perfect, I've considered all options and assessed what's required/appropriate/necessary. I don't want Mr NICEIC assessor saying 'you should have done this' or 'why didn't you do that?'

 

[telectrix]

why pull fuse when you have a henley block you can disconnect and reconnect live ( with all loads off, of course ). as for the earthing, if it's soldered onto the sheath of the supply cable, connect your main E to the tail. if you're not happy with it, get DNO to improve it.

 

[shagbite]

Ok, so what you're saying is I don't really need to involve the DNO? I assumed the earth connection to the sheath via choc block would need replacement? Also, if I pull the main fuse do I HAVE to fit a main isolator?

Just to remember, this will be my assessment job where the NICEIC will visit and inspect. I want to make sure all is perfect, I've considered all options and assessed what's required/appropriate/necessary.

I don't want Mr NICEIC assessor saying 'you should have done this' or 'why didn't you do that?'

he won't notice anything amiss if you hypnotise him with a wad of tenners sticking out of your back pocket.

 

[Johnlondon]

Ok, so just to be clear, no-one's got a problem with the earth connection from the incoming supply to the MET? Simply saw the stranded cable attached to the lead sheath via a choc block to the MET as not great but I suppose there's no reason why it's not satisfactory.

 

[Doug]

It looks like you have some strands of wire from the sheath of the supply cable, by which the DNO provides your main earth. These go into a connector block which connects via a Henley style block to the 3 existing CCU/DBs. If there is enough slack on the supplier's earth, the connector block could be replaced with an earth block beside the supply cables. Then 16mm earth cable from the (suitably labelled) earth block to your new consumer unit.

 

[Johnuk]

wow that is some poor work on the bonding

 

[brucelee]

Ok, so just to be clear, no-one's got a problem with the earth connection from the incoming supply to the MET? Simply saw the stranded cable attached to the lead sheath via a choc block to the MET as not great but I suppose there's no reason why it's not satisfactory.

Hi mate
thats how it was on the mother in laws i got supplier out to fit iso sort the earthing as it was 3 strands of what looked like the armoured strands out of swa soldered to the sheath and uprate the main fuse , new meter, new tails on there side
£39 British gas he didnt bat and eyelid at the earth changed fuse to 80 as it was all he had and wasnt told he was to change the fuse fitted the new digi meter and tails sealed and was on his way
I just sleeved the 3 strands and connected to the new external MET and he was happy with that and so was the assessor from elecsa