Split concentric after meter, queries

[baldelectrician]

Did an EICR that passed 5 years ago
Several things in the picture raised concerns for me.
Comments please - photo at end

First photo shows a split concentric in use AFTER the meter, the supply is a TNC-S supply and the split concentric has the following items

• Single insulated neutral conductors that are accessible to touch C2
• Unsleeved cpc on the split concentric C2
• Single insulated line conductor- this is thicker than normal and may be aluminium (have put this down as FI)
• Split concentric cable has neutral and earth wrapped around the inner line conductor and appears therefore to have neutral conductors acting as a armour in case of a fault listed as FI

Second photo

Gas meter (plastic incoming pipe) has copper outgoing pipe which goes underground and can induce

 

[timhoward]

After the meter isn't an issue in itself.
What is the route of the split-con? Does it stay above ground and is it visible and surface clipped once inside as it goes to the CU?
As well as the obvious single insulated issue I'm thinking about lack of over-current protection and whether it in fact needs RCD protection. And the lack of mechanical restraint of any nature.

The gas is definitely extraneous, I guess there's no bond inside where it enters?

 

[baldelectrician]

After the meter isn't an issue in itself.
What is the route of the split-con? Does it stay above ground and is it visible and surface clipped once inside as it goes to the CU?
As well as the obvious single insulated issue I'm thinking about lack of over-current protection and whether it in fact needs RCD protection. And the lack of mechanical restraint of any nature.

The gas is definitely extraneous, I guess there's no bond inside where it enters?

Cable goes under floor (I think it is concrete) and rises at consumer unit under stairs
It is inside brick cavity at the meter box and goes down.
There was no adequate continuity on the gas pipe work (0.11 ohms)

 

[loz2754]

Not sure about the FI for basic insulation exposed to touch. I would say that's a C2, no investigation necessary.

Unsleeved CPC would not warrant a code at all in my opinion, maybe just a comment. Unless there are two different earthing systems present that can be touched simultaneously, then it would be C2.

About the neutral and earth conductors wrapped around the centre line conductor, that's just how split concentric cable is constructed. It is not an armoured cable, and therefore cannot be used to satisfy the requirements for safe zones, and would probably need 30mA RCD up stream, depending on the installation route.

 

[Rockingit]

Split-con....... so, here's one for debate: This is all inside a locked cupboard that requires a 'tool' (mbox key) to open.

 

[timhoward]

Split-con....... so, here's one for debate: This is all inside a locked cupboard that requires a 'tool' (mbox key) to open.

I nearly said that! But here's the thing - it's a pre-pay meter.

 

[loz2754]

Split-con....... so, here's one for debate: This is all inside a locked cupboard that requires a 'tool' (mbox key) to open.

This argument has been raised before. My reply is that the customer, classed as a normal person, or even their child at the request of the parent, will be regularly opening the door to read the meter, and in this case to top up the meter. In my view, common sense would override that particular regulation.
Add to that the number of damaged doors that cannot be locked that we come across.

 

[littlespark]

Is concentric not classed as reinforced insulation? ie, not basic insulation

Used all the time by networks before the cutout....

 

[brianmoooore]

There are moulded heat shrink gizmos that are available for terminating s/concentric by providing the second layer of insulation..

 

[pc1966]

Is concentric not classed as reinforced insulation? ie, not basic insulation

Not the centre core connected to L as exposed here. When used by the DNO it all is enclosed in the cut-out.

It is in my mind fairly safe in the sense that a penetration by nail etc, has to go through at least N or E but of course N cannot be considered "safe" in the general sense as it is one of the live conductors. Of course DNO treat it as safe to bury, but that is no longer consider enough under BS regs.

As already mentioned it is probably not under the '3m rule' for fault protection.