Not sure if this is ok to connect

[russellsmiler]

Can I please ask the forum for advice for a work colleague of mine?
His recent purchase property has a detached garage (10m away from house) inside the garage is what is a standard garage type distribution board consisting of a 40 Amp 30 Ma RCD two type B MCB s 1 x32 amp 1x 6amp, this is connected by way of 6mm twin and earth (flat grey) underground back to a joint box adjacent to the main distribution board, and from here again in 6mm grey flat terminating in the dis board in a type b 32Amp mcb...(this is a new looking metal dis board so assume it was installed quite recently) (but not by new owner).
he wished to do various things so contacted a friend of is who works in the electrical industry on supply connections etc, the friend as run some cabling and I am now seeking some advice.

bear in mind there are no connections made as yet!!! the cable as been run from the house, underground and as been jointed ( not doubting that the joint would be DNO standard) from the joint one end goes into garage and ultimately would be replacing the 6mm grey flat, and from the joint the other end goes to an outdoor area (proposing to have hot tub and s few sockets) where a meter box ( like what you would have on a house) is positioned, inside the meter box the cable as been terminated in a DNO type 100amp fuse. and earth as been run from the negative to a ground spike a few meters away. this is the crunch!!! the cable used is a 35mm concentric aluminium CNE in a black PVC sheath.

Can I gather thoughts on this please ,
Thankyou
Russell

​

 

[flameport]

CNE cables are not permitted in any consumers installation.

The Electricity Safety, Quality and Continuity Regulations 2002

These Regulations replace the Electricity Supply Regulations 1988 (S.I. 1988/1057) and all subsequent amendments (S.I. 1990/390, S.I. 1992/2961, S.I. 1994/533, S.I. 1994/3021 and S.I. 1998/2971).

www.legislation.gov.uk

(4) A consumer shall not combine the neutral and protective functions in a single conductor in his consumer’s installation.

 

[ericmark]

Fact it uses an earth rod is good, that's what you need with anything outside and not class II. But the cable as said is not permitted.

 

[JohnW2]

CNE cables are not permitted in any consumers installation.

Indeed not.

However, what if he simply removed the connection between the neutral and earth rod, and then just use the earth rod to TT the garage? There would then be no CNE conductor within the installation.

Kind Regards, John

 

[SUNRAY]

We've been here before John, 'they' will start charging in saying you require the original earth to be extended to the TT'd section.

Hence the nasty problems created by the presence of the DNO and TT earths.

 

[securespark]

Yes, there's an issue with PDs between DNO and TT earths.

 

[SUNRAY]

Yes, there's an issue with PDs between DNO and TT earths.

Oh yes and don't I know it

 

[plugwash]

However, what if he simply removed the connection between the neutral and earth rod, and then just use the earth rod to TT the garage? There would then be no CNE conductor within the installation.

However there would be a neutral conductor that was only "single insulated".

 

[JohnW2]

We've been here before John, 'they' will start charging in saying you require the original earth to be extended to the TT'd section.

If the outbuilding is TT'd, then the 'original' (DNO) earth must not have a (touchable) presence in the outhouse

Hence the nasty problems created by the presence of the DNO and TT earths.

As above, no problem if the DNO earth is not accessible within the TTd outhouse.

Kind Regards, John

 

[JohnW2]

However there would be a neutral conductor that was only "single insulated".

Good point, which I overlooked!

I was addressing flameport's point about ESQCR, which, as I said, could be resolved simply by removing the connection between neutral and rod, and TTing the garage, but I overlooked that (assuming it was straight con) one would still be left with a cable that was not BS7671-compliant.

However, you've got me thinking now (always dangerous ). If it is a TN-C-S installation. such that the neutral is connected to the MET (hence arguably effectively a CPC), could one not try arguing that it was a 'single' cable (carrying the L) with an 'earthed outer covering' ? Not really a serious suggestion, but ...... !!

Kind Regards, John

 

[SUNRAY]

If the outbuilding is TT'd, then the 'original' (DNO) earth must not have a (touchable) presence in the outhouse

Totally agree, I wish these f*****g EICR inspectors understood that, come across 2 recently.

As above, no problem if the DNO earth is not accessible within the TTd outhouse.

Kind Regards, John

Totally agree.

 

[JohnW2]

Totally agree, I wish these f*****g EICR inspectors understood that, come across 2 recently.

What are they suggesting is the 'required alternative'?

Kind Regards, John

 

[SUNRAY]

What are they suggesting is the 'required alternative'?

Kind Regards, John

They have given C1 as no earth bonk/link etc and charged for adding a 16mm² between the two CU's.

And on a camp site we installed a 3ph DB in an outbuilding some 100m from the main intake, ensuring the SWA was safely terminated with the armour wires very well protected within the DB. First inspection highlighted lack of brass gland and fitted one, next inspection highlighted lack of adequate earth arrangements and pulled in a 25mm² single... however they ensured the new wire and the brass gland are only connected to the enclosure and claim to have isolated the earth bar from the enclosure for the TT earth. So the situation now is the socket in the outbuilding and the class1 light fitting are at TT earth and the enclosure at DNO earth.

 

[JohnW2]

They have given C1 as no earth bonk/link etc and charged for adding a 16mm² between the two CU's.

Exporting the DNO earth is obviously acceptable (whether or not a local TT rod is connected (or 'bonded' to it), but is certainly not the only acceptable approach. Do I take it that the armour was not adequate to qualify as a bonding conductor?

And on a camp site ..... So the situation now is the socket in the outbuilding and the class1 light fitting are at TT earth and the enclosure at DNO earth.

Hmmm - well I would think that probably is (now) a C1 !

Kind Regards, John

 

[SUNRAY]

Hmmm - well I would think that probably is (now) a C1 !

Kind Regards, John

I'm sure there is more labels on there but don't have pics.
One problem is all circuits are RCBO so can't prove the hazard without frigging the circuits.

And the underside where the brass glands are earthed to the enclosure, the larger (uncovered) was a plastic gland. Left and right are splitcon in plastic glands.