I think this is wrong, thoughts please

[Billsays]

Hi guys, been doing more testing and reporting on small blocks of flats and came across this scenario.

Block is PME with a small intake at the bottom containing most of the meters. The sub-mains/laterals then run through pvc conduit to the ccus in the flats where there is an Henly block making the PME connection. I think this is wrong as any fault current would have to go through the meter. What's your thoughts?
Pix below...

 

[telectrix]

totally wrong. the PME connection N-E must be made at the cut-out, before the meters. definitely a C2 at best.

 

[Billsays]

totally wrong. the PME connection N-E must be made at the cut-out, before the meters. definitely a C2 at best.

Tel there is a N-E connection in the Ryefield but it's the pvc conduit that buggers it up imho.

 

[telectrix]

but where is the main earthing conductor for each flat connected to N?

 

[Billsays]

but where is the main earthing conductor for each flat connected to N?

In a 3x3 pvc trunking above the ccu.

 

[telectrix]

then it's wrong. each flat's main earthing conductor shouls connect to N before the meters

 

[Ian1981]

Any N-E link to make the system TNCS should be done before the consumers installation starts, on the DNO's installation.

 

[Wilko]

If I've understood the installation correctly, it's prohibited by reg 543.4.1 and ESQC reg 8(4) is quoted also.

 

[Ian1981]

Got to say it's quite concerning to see that there are installations like this about
Who the hell is certifying this as compliant?

 

[Billsays]

Got to say it's quite concerning to see that there are installations like this about
Who the hell is certifying this as compliant?

No idea but it's been in service since 1980!

 

[Billsays]

If I've understood the installation correctly, it's prohibited by reg 543.4.1 and ESQC reg 8(4) is quoted also.

The PME connection is only just in the flat each time, before the Neutral goes into the ccu, it was because the meters are remote it means a fault current would go through the meter.
Some of the flats have had the meters moved into them, (that's the Henly blocks you can see above the trunking in my original post) and the pme connection is before meter so I have no issues with them.

 

[westward10]

This is very similar to another recent thread.

 

[Wilko]

The PME connection is only just in the flat each time, before the Neutral goes into the ccu ...

Ok, but where is the supplier's fuse? ( i.e. Can you describe the fusing arrangement for the building and the flats )

 

[Billsays]

Ok, but where is the supplier's fuse? ( i.e. Can you describe the fusing arrangement for the building and the flats )

Yes the service head is a 100A 3 phase PME job that feeds a Ryefield board. Each fuse feeds a flat. Some of the meters for the flats are mounted on a trunking next to the Ryefield board. As said the laterals are run in PVC conduit with no separate Earthing conductor.

 

[Wilko]

Sounds like the PME is done ok at the building cut out, but they have failed to link the MET to each of the flats. Instead they have created additional N-E links in contravention of reg 543.4.3 (is my thought).

 

[Rosco]

Are these properties in central London as I have seen some with a similar set up around the Southwark tube station area?

 

[Risteard]

Essentially what you have there are PEN/CNE conductors within the installation. Presumably this is within the BNO network, although without DNO authorisation there is almost certainly a breach of ESQCR there.