Concentric Cable

[HL8]

I have looked at a job, the guy wants a new fuseboard put in the shed, he has a incoming concentric SWA.. or whatever you want to call it which I can’t find a answer for, it looks like a 25mm single core “brown’’.. the sheathing is then twisted up and taken into the neutral block, This then feeds a existing fuseboard which is supplying a mobile home and garden lights (picture shown) 

I am going to take a 6mm 3 core SWA into the new she’s into a new consumer unit, running 2 double sockets, lights, and around 4 appliances (washing machine, dishwasher, tumble dryer, cooker) so looking around 30/40 amps to be pulled at any one time.

i read that you cannot place a RCD consumer unit on this instal as it’s a ‘concentric cable’ where the sheathing is used as the neutral. 
 

I’m struggling to add the picture of the installation   

 

[Evans Electric]

Where did you read that ?  

You need 10 posts on Forum before posting pics . 

 

[Andy™]

if its a concentric cable then it cannot be used for wiring complying with BS7671

 

[Phoenix]

The first thing to do is establish whether it is straight concentric (in which case as Andy says, it'll never comply because TN-C earthing isn't permitted without very special permission which you'd never get for a simple domestic shed

If its split concentric, then things arn't quite so bad, although you do run into a a bit of a problem if its buried direct (not as big as a problem as above though)

 

[Evans Electric]

i read that you cannot place a RCD consumer unit on this instal as it’s a ‘concentric cable’ where the sheathing is used as the neutral. 

Are you talking  about the main incomer here ?     Thats what I presumed. 

 

[HL8]

The main incoming is of a ‘telephone’ pole to a pillar, then Into a Henly block. out the pillar In that concentric cable, into another pillar 50 meters away, into a big grey 100amp fuse Henley block, with the neutral (the sheathing of the concentric cabe) joined in with the earth (PME).

i just need to know if I’m okay to wire a new instal to this set up, for sockets and lights in a shed next to this pillar. Having a night mare trying to find answers. 

 

[ProDave]

Who owns this cable?

It sounds to me like a DNO's supply but where is the meter?

If it's not a DNO cable then it does not comply with BS7671