Meter change..

[Simon35]

Just by way of an update, the meter replacer came, had a quick look, said something about asbestos and said he would have to contact Northern Power to replace the cut-out etc.

I was a bit busy at the time so didnt ask, but where would the asbestos be, in some gaskets maybe?

 

[ban-all-sheds]

Maybe he was behind the curve for his target of changes, and needed to shorten a few visits?

 

[westie101]

I was a bit busy at the time so didnt ask, but where would the asbestos be

Probably in the cast iron cut-out. If undisturbed it is safe and only in small quantities.
Northern Power will no doubt be in touch to change it at some point in the fusture, they'll probably do the tails to the meter at the same time

 

[Simon35]

I was a bit busy at the time so didnt ask, but where would the asbestos be

Probably in the cast iron cut-out. If undisturbed it is safe and only in small quantities.
Northern Power will no doubt be in touch to change it at some point in the fusture, they'll probably do the tails to the meter at the same time

OK thanks. Would they change the earthing arrangement generally, mines TN-S? Is there any advantage in PME? Presumably they change the cutout to a plastic cased isolator..

 

[westie101]

Would they change the earthing arrangement generally, mines TN-S? Is there any advantage in PME? Presumably they change the cutout to a plastic cased isolator..

The earthing will stay the same, there are no particular advantages to TNC-S exept to the DNOs as it saves us a cable core!!

They will change it to a modern plastic cut-out, dependant upon their proceedures they may fit an isolator but it is up to them

 

[dinopower]

I work for wpd south west and we change iron clad cutouts alive if we deem it safe to do so, we dont always able to provide an earth though as we have old dc cables which we cant provide an earth because of the old jointing procidures, we would normally notchange tails though as they belong to the supplier, we may do if it is dangeourous.

 

[bernardgreen]

there are no particular advantages to TNC-S exept to the DNOs as it saves us a cable core!!

I have to say I was a bit puzzled when watching the connection being made to the street cable that the armouring could not have been utilised as a conductor for an earth. I can understand the cost saving when it is an over head supply but un-broken earthed armour is necessary ( or is it ? ) in an underground cable.

 

[RF Lighting]

The earthed 'armour' is the combined neutral and earth conductor (CNE). This surrounds a single line conductor.

If the DNO were to provide a TN-S supply then the earthed 'armour' would need to surround both a line and a neutral core, hence TN-C-S saves on the additional neutral.

 

[bernardgreen]

The earthed 'armour' is the combined neutral and earth conductor (CNE).

The street cable was a four core cable with wave laid armouring. Only the cable to the cut out in my meter box was CNE

 

[RF Lighting]

So they saved a core between the main cable and your cutout.

 

[westie101]

On an older 4c lead sheathed cable the steel tape armour cannot be guaranteed to be continuous through joints or on older cable corrosion so the lead sheath will always be the earth.

On a 4c waveform the wave should be connected to earth to comply with ESQCR and can be used as such. At joint positions where we are giving a TNC-S supply we would bond the earth to the neutral (that is not to say every DNO will as it depends on the way their system is configured!